DE29522427U1 - Electro-optical fibre=optic interconnection module for data transfer between appts. - includes surface mounting type connector coupled to mother board of host computer, laser diode semiconductor integrated circuit and laser diode module - Google Patents

Abstract

The laser diode (LD) module (50) converts serial data received from the mother board to an optical signal. A photodiode (PD) semiconductor integrated circuit converts another optical signal to serial data. A circuit board (30) carries the connector (32), the LD (33) and PD integrated circuits, LD (51) and PD (41) shielding plates, two frames (10,20) for holding the circuit board, LD (50) and PD (40) modules. The LD and PD are connected to a side of the circuit board mounted with the connector. The circuit board has variable resistors (34) for adjusting a drive current of the LD module and biassing the PD.

Description

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LINENWEAVER & CARPENTER

EUROPEAN PATENT ATTORNEYS

Dipl.-Ing. H. Leinweber (19.-5 &eegr; Dipl.-Ing. Heinz Zimmermann Dipl.-Ing. A. Gi. v. Wengersky Dipl.-Phys. Dr. Jürgen Kraus Dipl.-Ing. Thomas Busch

Rosental 7

M-.-ViM D-80331 Munich
TEL(089) 231124-0
Fax (089) 231124-11
TLX 528191 LZPATD

Our Zelcftan

kst>k/El366-O3ET

MATSUSHITA ELECTRIC INDUSTRIAL CO.,LTD.,

Tokyo/Japan

Fiber optic cable 1

The invention relates to a fiber optic module which can be used in a device suitable for carrying out data transmission between different apparatuses.

Heretofore, fiber optic modules of the type shown in Figs. 17 to 13 have been known (disclosed in JP-A-3-218134). Fig. 17 is a plan view of a prior art fiber optic module comprising laser diode (LD) modules 1 for transmitting an optical signal to a printed circuit board 3 having a width of 76 mm and a length of 75 mm, photodiode (PD) modules 2 for receiving the optical signal, semiconductor ICs 4 and 5 for converting the optical signal into an electrical signal, and a terminal 6 for transmitting

of the electrical signal to a main board (not shown in the drawing).

Fig. 18 is a sectional view of a main part of a lower frame for the fiber optic module of the prior art. The fiber optic module of the prior art is fixed to the main board (not shown) by means of a spacer 8 and a J-shaped clip 9 formed on the lower frame 7b.
10

v _: ^: Fig. 19 is a holding mechanism for the

A sectional view showing a fiber optic module to be held by the main board according to the prior art. As can be seen from the figure, the circuit board 3 is inserted into a rear part of the lower frame 7b and then held by the upper frame 7a and the lower frame 7b.

However, as shown below, state-of-the-art fiber optic modules have some disadvantages.

1) The electrical signals are transmitted on a parallel data basis, and although all parallel signals are 8 bits, for example, the number of signal lines for transmitting the parallel signals and other signals increases to as many as 50, which requires large-sized connectors and semiconductor ICs for serial/parallel conversion, and as a result, the entire unit must inevitably be designed in a large size. Furthermore, not only does the large size of this unit itself run counter to the current trend of rapid miniaturization of processing computers, but it also greatly limits the design flexibility of the main board for the system manufacturers.

2) The attachment of the fiber optic module to the main board in the prior art is effected by means of the J-shaped clip 9 in the form of a resin leg extending from the lower frame 7b, as already explained with reference to Fig. 18. This requires a large hole as an opening for attachment in the main board, which greatly limits the design flexibility of the main board for the system manufacturer. Because fiber optic modules in the prior art have a structure in which the load caused by the force applied to attach and detach the optical fiber is applied to the J-shaped clip 9 and the lead (not shown) of the connector 6, breakage of the J-shaped resin clip 9 made of a resin or poor connection of the connecting lead is often caused, with the result of deterioration in the reliability of the fiber optic module.

Furthermore, for the purpose of avoiding any voltage applied to the lines of the LD modules 1 and PD modules 2, the accuracy of all parts must be increased and therefore, part inspection (such as part acceptability check) becomes necessary, which makes it difficult to obtain a low-cost fiber optic module.
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3) The fiber optic module according to the state of the art is fixed by soldering the connector 6 to the control board 3 and then the signal lines of the connector 6 are connected directly to the main board by soldering. The need for this work prevents the realization of a low-cost fiber optic module.

A) In the method shown in Fig. 19 for holding

of the control panel 3, a warp occurs in the control panel 3, which significantly reduces the reliability of the control panel 3.

Furthermore, the holding method shown in Fig. 19 requires a sufficient length of the panel itself and also a sufficient panel holding length L, which prevents the realization of a miniaturized fiber optic module.

5) Because most of the area of the control board 3 is exposed, the prior art fiber optic module is susceptible to electrostatic destruction when a worker handles the prior art fiber optic module or a user mounts the prior art fiber optic module on the main board, resulting in poor reliability and poor cost-performance ratio of the fiber optic module.

6) During long-term storage, dust or foreign matter enters the LD and PD modules into which optical fibers are to be inserted, causing unusable or poor connection between the optical fiber and the module, resulting in a serious deterioration of the reliability of the fiber optic module.

Accordingly, an object of this invention is to provide a fiber optic module which can solve the aforementioned problems in the prior art and which can be manufactured in a compact format, allowing high design flexibility for the main board, at low cost and with high reliability.

According to one aspect of this invention, the above object is achieved by providing a fiber optic module comprising a connector connected to a main board of a host computer, an LD holder IC for converting serial data received from the main board into an electrical LD signal for a laser diode, an LD

A module for converting the LD electrical signal into an LD optical signal, a PD module for converting an optical photodiode signal into a PD electrical signal, a PD semiconductor IC for converting the PD electrical signal into PD serial data, a circuit board having the terminal and supporting the LD semiconductor IC and the PD semiconductor IC, an LD shielding plate for electrically shielding the LD module, a PD shielding plate for electrically shielding the PD module, a first frame for holding the circuit board, the LD module and the PD module, and a second frame for holding the circuit board, the LD module and the PD module. In the fiber optic module, the connector may be formed in an external mounting type, i.e., a circuit board structure, the leads of the LD module and the PD module may be connected to the side of the circuit board where the connector is mounted, the circuit board may have a variable LD resistor for setting a drive current for the LD module, the variable LD resistor may be provided on a side of the circuit board opposite to the connector, the circuit board may have a variable PD resistor for detecting a signal of the PD module, the variable PD resistor may be provided on a side of the circuit board opposite to the connector, three signal processing semiconductor ICs or less may be provided, the external configuration of the circuit board may have dimensions of 17 mm to 25.4 mm in width and 30 mm to 50 mm in length, the external dimensions of the fiber optic module may have a width of 19 mm to 25.4 mm, a length of 45 mm to 65 mm and a height of 9 mm to 25.4 mm, the second frame may have latches for coupling the optical signal, the first frame may be provided with projections for protecting the latches, the first frame and the second frame may be made of a resin material, the first frame and the second frame may have means for holding the circuit board, the holding means may be in the form of a snap-in

mechanism, the front end of the circuit card can be held by the first and second frames, the first frame can have a cross member, a recess provided in the cross member can be used to hold at least a rear part of the circuit card, and the data transmission speed of the optical signal can be 200 Mbit/s or more.

The invention is described below with reference to the drawing, to which reference is expressly made at this point for all details not explained in more detail in the description. In the drawing:

Fig. 1 is a perspective view in block diagram form of a fiber optic module according to a first embodiment of the invention;

Fig. 2 is a perspective view of a fiber optic module according to a second embodiment of the invention; 20

Fig. 3 is an exploded perspective view of a portion of a fiber optic module according to a third embodiment of the invention;

Fig. 4 is an exploded perspective view of another part of a fiber optic module according to the third embodiment of the invention;

Fig. 5 is a sectional view of a main part of a fiber optic module according to a fourth embodiment of the invention;

Fig. 6 is a sectional view of a main part of a fiber optic module according to a fifth embodiment of the invention;

Fig. 7 is a perspective view of a lower frame for a fiber optic module according to a sixth embodiment of the invention;

Fig. 8 is a sectional view of a main part of a fiber optic module according to a seventh embodiment of the invention;

Fig. 9 is a sectional view of a fiber optic module according to an eighth embodiment of the invention;

Fig. 10 is a sectional view of a fiber optic module according to a ninth embodiment of the invention;

Fig. 11 is a perspective view of a fiber optic module according to a tenth embodiment of the invention;

Fig. 12 is a plan view of a fiber optic module according to an eleventh embodiment of the invention; 20

Fig. 13A is an exploded perspective view of a fiber optic module according to a twelfth embodiment of the invention;

Fig. 13B is a perspective view of the fiber optic module according to the twelfth embodiment of the invention in the assembled state;

Fig. 14 is a perspective view of a fiber optic module according to a thirteenth embodiment of the invention;

Fig. 15 is a plan view of the fiber optic module according to the thirteenth embodiment of the invention;

Fig. 16 is a perspective view of a module cap of the fiber optic module according to the thirteenth embodiment of the invention;

Fig. 17 is a plan view of a prior art fiber optic module;

Fig. 18 is a sectional view of a main part of a lower frame for the fiber optic module according to the prior art;

Fig. 19 is a sectional view of a main part showing how a circuit board of the fiber optic module according to the prior art is held. 15

Fig. 20 shows an eye pattern of an arbitrary pattern transmitted by the fiber optic module according to the invention;

Fig. 21 shows a bit error rate (BFR) of the fiber optic module according to the invention;

Fig. 22 is a circuit diagram of a circuit for measuring the bit error rate and

Fig. 23 is a block diagram of the fiber optic module according to a fourteenth embodiment of the invention.

In the following description, like reference numerals designate like parts.
30

Fig. 1 shows a block diagram of a fiber optic module

according to a first embodiment of the invention.

In Fig. 1, a printed circuit board (hereinafter referred to as PCB) 30 is used to send an electrical signal (serial) received at a PCB terminal 32

data) to a laser diode (LD) driver 33 for operating an LD element arranged within an LD module 50 (not shown in Fig. 1, see Fig. 8) and for transmitting the data in the form of an optical signal to an optical fiber (not shown) inserted into an opening 52 of the LD module 50. On the other hand, a photodiode (PD) module 40 receives an optical signal from an optical fiber inserted into an opening 42 of the PD module 40 (fitting not shown), converts the optical signal into a current with a PD element (not shown in Fig. 1, see Fig. 8) , and sends the current to an impedance conversion amplifier part 35a of an amplifier 35 in the form of a semiconductor IC for converting the current into a voltage. Further, the optical analog signal in the form of the voltage is converted into a digital signal with a shaping circuit part 35b and transmitted to the main board in the form of serial data through the PCB connector 32. In the fiber optic module according to the invention, the PCB connector 32 requires only about 22 signal lines because the transmission of the electrical signal is carried out in the form of serial data. This means that not only the format of the PCB connector 32 itself can be made extremely compact, but also the size of the PCB connector 32 can be made extremely compact. but also the PCB 30, with the result that reliable data transmission at a speed of more than 130 Mbit/s can be realized with the fiber optic module. In this regard, it is noted that although in the first embodiment of the invention the amplifier 35 is formed in the form of a single semiconductor IC, the impedance conversion amplifier part 35a may be formed separately from the shaping circuit part 35b, and these parts 35a and 35b may each be formed as individual semiconductor ICs, with substantially the same effects as in the embodiment described above with reference to Fig. 1.

High-speed data transmission can be achieved, for example, with LD elements that convert light at

a wavelength of 780 mn with a power of 5 mW at maximum rated voltage. The fiber optic module of the invention conforms to the ANSI χ 3T9.3 Fiber Channel standard and carries out data transmission speeds of 133 Mbit/s, 266 Mbit/s, 531 Mbit/s and 1061 Mbit/s. A typical function is shown in Fig. 20. Fig. 20 shows an eye pattern of an arbitrary pattern transmitted at a transmission speed of 531 Mbit/s through the fiber optic module of the invention. Fig. 20 illustrates a voltage level obtained by converting the optical signal emitted from the LD module 50 with an optoelectric conversion element having a sufficient bandwidth as a function of time. The figure shows an optical signal observed with an oscilloscope which has passed through a 400 MHz Bessel filter. In Fig. 20, reference symbol Pd denotes an emission level representing the standard amplitude width, Po denotes an overshoot amplitude normalized to the value Pd · allowable according to ANSI χ 3T9.3, and Pu represents an allowable undershoot amplitude normalized to the value Pd. Compared with the allowable overshoot Po and the allowable undershoot Pu, the optical signal from the fiber optic module of the invention is certainly a good signal with a sufficient distance from the allowable values. Reference symbol Pi shows an eye diagram provided according to ANSI χ 3T9.3 applied to the data of the invention. The fact that there are no errors within the eye diagram confirms that the fiber optic module of the invention produces a sufficient distance from the allowable values. In Fig. 20, a circular period of the optical signal of 1.88 ns is plotted for the purpose of a good understanding of the operation of the invention at 531 Mbit/s.

Fig. 21 shows a bit error rate (BFR) of the fiber optic module according to the invention. Fig. 21 illustrates the

1 1

Bit error rate on a logarithmic scale as a function of the optical power received by the optical sensor. The bit error rate is measured with a bit error rate tester connected to the optical sensor via the fiber optic module. The measuring circuit is shown as an example in Fig. 22. Serial electrical data 93 is transmitted from the bit error rate tester 90 to the LD driver 33 via the PCB connector 32. The LD driver 33 converts the serial electrical data into an optical signal for stimulating the LD module 50. The optical signal emitted by the LD module is transmitted to a PD module 40 via optical cables 92 and a light attenuator 91. The optical signal transmitted to the PD module 40 is then converted into an electrical signal by an amplifier 35 and transmitted to the bit error rate tester 90 in the form of a serial data output 94 through the PCB connector 32. The bit error rate shown in Fig. 21 means a ratio of the serial data 94 that has passed through the fiber optic module array 100 compared with serial data 93 before passing through the array 100. For example, if an error occurs in one bit during the transmission of 1000 bits of data, the ratio becomes 10~3. The received power shown in Fig. 21 represents the intensity of the optical signal entering the PD module 40 shown in Fig. 22. The optical signal emitted from the LD module 50 is variably adjusted by the light attenuator 91 as a level of an incoming optical signal to control the received power or intensity of the signal transmitted to the PD module 40. The diagram of Fig. 21 is obtained using the measuring circuit shown in Fig. 22 in the manner described above.

In Fig. 21 the actual points plotted

obtained at received powers of -20.5 dBm -20 dBm, 19.5 dBm and -19 dBm. A linear extra polished line through

The four plotted points above show that a BFR of 10~ ¹² is achieved at a received power of -18.6 dBm, which clearly shows that the bit error rate of 1O~ ¹² required by ANSI χ 3T9.3 is achieved at a minimum received power of -15 dBm.

Next, the compact construction of the PCB 30 will be explained with reference to Fig. 1.

Conventional expansion slots for inserting a main board into a host computer are in most cases spaced 25.4 mm apart, so in these cases a fiber optic module must be designed to fit the 25.4 mm intervals so that the module can be mounted horizontally or vertically on the main board. In other words, it is desirable to make the widthwise extension of the PCB 30 shorter than 25.4 mm.

If the PCB terminal 32 has 22 pins (arranged in two columns of 11 rows) with pin pitches of 1.27 mm, the terminal has a width direction dimension of about 14 mm and a length direction dimension of 2.5 mm, with the result that the outer contour of the PCB terminal 32 including its housing and lead parts (not shown) has a width direction dimension of 17 mm and a length direction dimension of 5 mm. The outer contour of the semiconductor ICs (33 and 35) has a width direction dimension of 7 mm and a length direction dimension of 10 mm (or may have a width direction dimension of 10 mm and a length direction dimension of 7 mm). When not only the outer contour dimensions of the PCB terminal 32 and the semiconductor ICs but also the parts attached to the PCB 30 and the wiring pattern of the PCB 30 are taken into consideration, it is desirable that the outer contour of the PCB 30 has an

elongation in the width direction of 19 mm or more and a longitudinal extent of 30 mm or more. Even if the number of semiconductor ICs for use in signal processing is increased up to 3, the longitudinal extent of the PCB 30 can be restricted to be 50 mm or less. Therefore, it is desirable to set the width of the PCB 30 to a value between 17 mm and 25.4 mm and the length of the PCB 30 to a value between 30 mm and 50 mm. In the first embodiment of the invention, the width of the PCB 30 is set to 22.5 mm, the length to 32 mm (the longest portion) and the thickness to 1.6 µm (for providing mechanical strength) to thereby realize a reliable PCB 30. Furthermore, the PCB terminal 32 is formed in an external mounting manner, i.e., it is mounted as a PCB structure on a main surface of the PCT, and only two of the semiconductor ICs are used for signal processing, thereby realizing a small size of the PCB 30. In the first embodiment of the invention, the thickness of the PCB 30 is not particularly limited. In this regard, since the use of the PCB terminal 32 in an external mounting manner enables the minimization of unnecessary radiation emitted from the terminal, it is noted that such a terminal is particularly useful for a compact fiber optic module of the type described above. 25

Fig. 2 shows a perspective view of a fiber optic module according to a second embodiment of the invention. The compact construction of the fiber optic module is explained with reference to Fig. 2. 30

The PCB 30 is used to form an assembly or a

Fiber optic module is held by an upper frame 10 and a lower frame 20. On the PCB 30 are mounted an LD driver 33 formed as a semiconductor IC for operating an LD element (see Fig. 8), variable resistors 34 for adjusting

a current for driving the LD element (not shown) and a PCB connector for connecting to a main board (not shown). To keep the average wall thickness of the upper frame 10 constant, a thin wall portion 17 is provided in the upper frame 10.

As already explained in connection with the compact construction of the PCB 30 of Fig. 1 according to the first embodiment, expansion slots for inserting a main board into a host computer are arranged at intervals of 25.4 mm in many cases, so that it is necessary to construct a fiber optic module so that it can be mounted horizontally or vertically on the main board with respect to the expansion slots arranged at intervals of 25.4 mm. Therefore, it is desirable that the module have a widthwise dimension of 25.4 mm or less. In the illustrated example, the PCB 30 is constructed to have a widthwise dimension of 17 mm to 25.4 mm and a lengthwise dimension of 30 mm to 50 mm. In order to prevent any displacement in the direction perpendicular to the width direction of the PCB 30, it is desirable that the frame of the fiber optic module be larger than the width of the PCB 30 in terms of the width direction dimension. For example, when the width of the frame is 2 mm or more larger than the width of the PCB 30, a step for preventing displacement of the PCB 30 may be provided in the frame. Therefore, when considering the width direction dimension of the PCB 30, the width direction dimension of the fiber optic module is desirably selected to be between 19 mm and 25.4 mm.

Given that the PCB 30 has a longitudinal dimension between 30 mm and 50 mm and the LD module 50 has a length of about 15 mm, it can next be said with respect to the longitudinal direction that the fiber optic module has a length between 4 5 mm and 65 mm. This means that the

The longitudinal dimension of the fiber optic module is desirably set to a value between 45 mm and 65 mm.

As already explained in connection with the height direction, the height of the module is desirably set to 25.4 mm or less in view of the fact that the fiber optic module of the present invention must be arranged vertically or horizontally for installation between the extension slots of the host computer. In addition, when consideration is given to the case where two fiber optic modules of the present invention are double-packed on the main board, the module height is particularly preferably set to 12.7 mm or less. Further, when consideration is given to a mechanism for preventing erroneous insertion of an optical fiber connector (not shown) to be fitted into the fiber optic module, reception of the optical fiber connector, frame strength, etc., it is particularly preferable that the fiber optic module has a height of 9 mm or more. Accordingly, the fiber optic module preferably has an extension in the height direction of about 9 mm to 25.4 mm.

Under the above-mentioned conditions, the embodiment of the invention shown in Fig. 2 realizes a very small-sized module with a width of 25.4 mm, a length of 50.8 mm and a height of 11.5 mm. If the functions necessary for the operation of a fiber optic module are sufficiently incorporated into the compact external dimensions, it is needless to say that the flexibility of the main board design can be greatly increased by the system manufacturers.

Fig. 3 and 4 together show explosive,

perspective views of a fiber optic module according to a third embodiment of the invention. In Figs. 3 and 4, a laser diode module (hereinafter referred to as LD module) 50

for emitting an optical signal and a photodiode module (hereinafter referred to as PD module) 40 for receiving an optical signal are mounted on a printed circuit board (hereinafter referred to as PCB) 30, to which a PD shield plate 41 and an LD shield plate 51 are fixed to prevent electromagnetic or electrostatic noise. Further fixed to the PCB 30 are a PCB connector 32 for establishing an electrical connection with a main board 60, an LD driver 33 formed as a semiconductor IC for driving the LD module 50, and variable resistors 34 for adjusting a current for driving the LD module 50 or for adjusting the detection level of a signal received with the PD module 40. For the purpose of effectively utilizing the mounting area of the PCB 30, a PCB connector 32 of an external attachment type is used. and the variable resistors 34 are mounted on the back of the PCB terminal 32. Since the PCB terminal 32 is used in the fiber optic module of the present invention in an externally mounted manner, the need for the step of manually soldering a connection, which was necessary in the prior art, could be eliminated, with the result that an inexpensive fiber optic module can be realized on the basis of automatic fabrication. Furthermore, not only the variable resistors 34 but also chip resistors or capacitors or circuit parts such as semiconductor ICs can be mounted on the back of the PCB terminal 32 to realize a compact PCB 30.

In addition, the step of adjusting during assembling the fiber optic module can be simplified because the variable resistors 34 are arranged on the top of the PCB 30. In other words, because the PCB terminal 32 of the PCB 30 for assembling/adjusting the fiber optic module is attached to a mounting substrate of the PCB 30, compared with the case where the variable resistors 34 are attached to the same

side as the PCB terminal 32, in the case of mounting the variable resistors 34 on the top of the PCB 30, the adjustment work on the fiber optic module can be more efficiently performed by one worker. Therefore, the more efficient adjustment work leads to the realization of an inexpensive fiber optic module.

All of the PD and LD lines 47 and 57 have a comparatively large contact area (not shown) on their side facing the PCB terminal 32 to improve the efficiency of assembling the PCB 30. On the other hand, the main board 60 is also provided with a main terminal matching the PCB 30.

The PCB 30 provided with the PD module 40, the LD module 50, etc. is detachably secured by means of a snap-on fastening mechanism consisting of a projection 12 on the upper frame 10 and a recess 22 on the lower frame 20, so that the resulting assembly including the upper frame 10, the lower frame 20 and the PCB 30 forms a fiber optic module. The PD module 40 and the LD module 50 mounted on the PCB 30 are fixed to the upper frame 10 and the lower frame 20 by means of a PD shield plate 41 and an LD shield plate 51 formed of leaf springs, respectively. Furthermore, the PD shield plate 41 and the LD shield plate 51 are fixedly mounted on the PCB 30 by soldering or other means and are surrounded by the lower frame 20, so that the PD shield plate 41 and the LD shield plate 51 can be fixed with high mechanical stability. Since the shield plate 41 and the shield plate 51 are electrically insulated from the main board 60 by means of the lower frame 20, any short circuit or leakage of the plates with respect to the parts mounted on the main board 60 can be avoided, thereby realizing a reliable fiber optic module.

The lower frame 20 is provided with latches 23 for coupling the optical signal to other fiber optic modules so that the latches 23 can be brought into tight engagement with connectors of the optical fibers (not shown).

After preliminary rough arranging the detachably secured fiber optic module in its position on the main board 60 by fitting the PCB connector 32 into the main connector 62, the fiber optic module is completely fixedly arranged on the main board 60 by means of self-tapping screws ^70. More specifically, the self-tapping screws 70 are passed through main openings 61 arranged in the main board 60, openings 21 in the lower frame and openings 31 in the PCB and then tightly tightened into openings 11 in the upper frame, whereby the fiber optic module is completely fixed on the main board 60.

In general, a reduction in positioning accuracy between the main terminal 62 and the PCB terminal 32 results in a load being applied to the respective leads (PD leads 47 and LD leads 57) of the PD module 40 and the LD module 50. The reason for this is that although the respective leads of the PD module 40 and the LD module 50 are fixed to the PCB 30 by soldering or the like, the PCB terminal 32 is also fixed to the PCB 30 by soldering or the like. For this reason, if the positioning accuracy of the main connector 62 with respect to the main holes 61 and the positioning accuracy of the PCB connector 32 with respect to the PCB holes 31 are not improved, these positioning errors result in a load being applied to the respective leads of the LD module 50 and the contact pieces of the PCB 30 (not shown). More specifically, if the main connector 62 is inaccurately positioned at a greater distance from the main

openings 61, the PD lines 47 and the LD lines 57 and the contact pieces of the PCB 30 are subjected to a tensile stress, while, on the contrary, if the main terminal 62 is improperly placed too close to the main openings 61, the PD lines 47 and the LD lines 57 and also the contact pieces of the PCB 30 are subjected to a compressive stress. These stresses result in the reliability of the fiber optic module being significantly reduced. To avoid these tensile and compressive stresses, it is necessary to improve the positioning accuracy of the connectors, which undesirably increases the cost of the fiber optic module. It goes without saying that similar adverse effects also arise from the PCB connector 32. 15

However, according to the third embodiment of this invention, in which the main openings 61, the openings 21 in the lower frame and the openings 31 in the PCB are set to have a diameter of 3.2 mm and the openings 11 in the upper frame are set to have a diameter of 2.2 mm, and in which the fixing of the fiber optic module is effected by means of self-tapping screws 70 (having a diameter of about 2.6 mm), the requirements for the positioning accuracy of the main terminal 62 with respect to the main openings 61 and the positioning accuracy of the PCB terminal 32 with respect to the openings 31 of the PCB can be reduced, so that the stresses caused by the tensile and compressive stresses applied to the leads (47 and 57) of the PD module 40 and the LD module 50 and also to the contact pieces of the PCB 30, which have been a great problem in the prior art, can be eliminated. to create a reliable fiber optic module. Furthermore, because the requirements for the positioning accuracy of the parts can be significantly reduced compared to the state of the art,

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can not only simplify the manufacturing control when arranging the PCB terminal 32 of the PCB 30, but also reduce the requirements for the accuracy of the parts used in the PCB 30 and the PCB terminal 32, thereby realizing a very low-cost fiber optic module.

The above-mentioned numerical values for the openings 11 in the upper frame, the openings 21 in the lower frame, etc. are given merely as an example, and therefore, this invention is not limited to these specific values. Regarding the arrangement according to the third embodiment of this invention, it is noted that values other than the above numerical values may be employed with substantially the same effects as those described above.

In this way, if the fiber optic module is made compact and small in size and provided with indispensable minimum functions, the system manufacturer can also design the main board with high flexibility. That is, because the fiber optic module according to the invention is made compact, taking up little space on the main board and the attachment of the fiber optic module requires only 3 small holes, the main board can be designed with high flexibility.

In addition to the advantages set out above, the arrangement of the three openings (openings 11 and 21 in the upper and lower frames, respectively, and main openings 61) forms such an isosceles triangle that stresses caused by attachment and removal of the fiber optic module are ideally distributed, with the result that a fiber optic module with high reliability is realized.

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Fig. 5 is a sectional view of a main part of a fiber optic module according to a fourth embodiment of the invention. In the drawing, the fiber optic module comprising a PCB 30, an upper frame 10 and a lower frame 20 is fixed to a main board 60 by means of self-tapping screws 70 which pass through main holes 61 and holes 21 in the lower frame into holes 11 in the upper frame and are then tightened in the holes 11. The electrical connection between the fiber optic module and the main board 60 is made by means of a PCB connector 32 and a main connector 62.

The holes 11 and 21 in the upper and lower frames, respectively, can also be used as reference holes for checking the acceptability of the upper frame 10 and the lower frame 20, respectively. Since the three holes 11 in the upper frame and the three holes 21 in the lower frame are set to have a draft angle of 0° at the time of their molding, the accuracy of the respective holes (holes 11 and 21 in the upper and lower frames, respectively) can be kept high. Since the accuracy of the holes can be kept high, the inspection of the parts can be simplified if tools designed to check the acceptability of the parts are made, dedicated to the holes. In other words, the holes 11 and 21 in the upper and lower frames, respectively, can be used not only as holes for attaching the fiber optic module to the main board, but also as holes for checking the parts.

Furthermore, the fiber optic module according to the invention is arranged in such a way that stresses which are applied to the fiber optic module and which are caused when the connectors of the optical fibers are attached and removed are absorbed by three self-tapping screws 70. In particular,

the specification of Japanese Industrial Standards JIS regarding optical fiber modules stipulates 9ON (newtons) with respect to the force applied when attaching and detaching the connector of the optical fiber, so that in order to satisfy this specification, it is desirable that the tapping screws 70 have a diameter of 1.3 mm or more. Moreover, from the viewpoint of safety design, the tapping screws 70 are set to have a larger diameter, desirably 2 mm or more. Since the tapping screws 70 in the optical fiber module v- ^w of the present invention are set to have a diameter of 2.6 mm, a reliable optical fiber module with a safety factor of three or more is realized.

Although in the fourth embodiment of the invention, the fixing of the main board 60 was achieved using the self-tapping screws 70, insert nuts (not shown) may be installed in the holes 11 of the upper frame and the self-tapping screws 70 may be replaced by ordinary small screws (such as small Phillips screws or small slotted screws) or the like, thereby producing substantially the same effect as in the example described.

When the fiber optic module has a structure according to the fourth embodiment shown in Fig. 5, it is clear that not only breakage of the legs of the frame made of a resin can be avoided, but also insufficient electrical connection of the lines, which has been a problem in the prior art.

Fig. 23 is a block diagram of a fiber optic module according to the fourteenth embodiment of the invention. In contrast to the fiber optic module according to Fig. 1, the fiber optic module according to Fig. 23 is provided with a semiconductor integrated circuit.

circuit (IC) manufactured serial-parallel converter 36 for converting serial data 93 into parallel data 95 and a parallel-serial converter 37 formed in the form of a semiconductor IC for converting parallel data 96 into serial data 94 and a PCB connection 32 as a replacement for the PCB connection 38.

More specifically, parallel data 96 output from the main board is supplied to the parallel-to-serial converter 37 on the PCB 30 through the PCB connector 38 for conversion into serial data. In contrast, serial data 93 obtained from optical data conversion is converted into parallel data 95 by the serial-to-parallel converter 36 and then transmitted to the main board. The PCB connector 38 of this embodiment is different from the PCB connector 32 described above and shown in Fig. 1 because the data transmitted from or to the main board is parallel type data, which is different from the data shown in Fig. 1. Specifically, the number of connection pins of the PCB connector 38 is greater than that of the PCB connector 32 shown in Fig. 1.

Fig. 6 is a sectional view of a main part of a fiber optic module according to a fifth embodiment of the invention. This embodiment is arranged such that a PCB 30 is detachably attached to an upper frame 10 and a lower frame 20 by means of a snap-on fastening mechanism, as already described in connection with the third embodiment of Fig. 3, but it differs from the embodiment of Fig. 3 in that the rear part of the PCB 30 is also slightly pressed down under the influence of an elastic deformation of a cross member 14 of the upper frame 10 in Fig. 6. More specifically, at the openings 11 of the upper frame in the region of a contact surface between the cross member having the openings 11

14 of the upper frame and the PCB 30, a step (shown exaggerated for clarity in the drawing) of about 0.2 mm is provided. When such an arrangement is adopted, handling of the fiber optic module in the detachably attached state becomes easier. In other words, because not only the front part of the PCB 30 is held by the snap-on fastening mechanism, but also the rear part of the PCB 30 is held by the cross member 14 on the lower frame 20, a more stable fiber optic module arrangement can be realized, so that not only the attachment of the fiber optic module to the main board 60 but also the handling of the fiber optic module itself can be simplified.

The prior art PCB is arranged so that the rear end and the front end of the PCB are pressed down by the frames, thereby causing a warpage problem. On the other hand, this warpage problem can be solved in the prior art if the PCB 30 according to the fifth embodiment of the invention is arranged so that it is supported at its frontmost part and a part slightly rearward from its central part. Moreover, while the prior art arrangement requires specific leverage ratios (lengths) for the PCB, the lower frame and the upper frame, the arrangement according to this embodiment can eliminate the need for maintaining such leverage ratios and therefore the fiber optic module according to the invention can be easily manufactured in a small size.

Fig. 7 shows a perspective view of a modification of the lower frame 20 which can be used in a fiber optic module according to a sixth embodiment of the invention.

In the sixth embodiment of the invention, the upper frame 10 and the lower frame 20 are made of polybutylene terephthalate (PBT) mixed with 10-30% glass, with the result that the frames have excellent strength and durability. In particular, this material of the frames improves the strength of the pawls 23 of the lower frame 20 for attaching and detaching an optical fiber connector. In addition, in order to reduce the forces applied to the pawls 23 of the lower frame 20, projections 16 (not shown in Fig. 7, see Fig. 5) of the upper frame are provided on the upper frame 10 (not shown in Fig. 7, see Fig. 5) of the upper frame, which come into contact with corresponding projections 26 on the lower frame arranged at the roots of the pawls 23. The lower frame 20, which is subjected to a large load caused by the attachment and removal of an optical fiber connector, is provided with a base plate 25 and a bar 24 to increase its overall rigidity.

Although the frames of both sixth embodiments of the

Invention are made of PBT material, this invention is not limited to the above specific example, but other suitable materials may be used if necessary.
25

Fig. 8 is a plan view of a main part of a fiber optic module according to a seventh embodiment of the invention, in which the lower frame 20, the PCB 30, the LD module 50 and the PD module 40 are shown in a partially cutaway plan view for detailed explanation. In the case of ordinary fiber optic modules, it is a prevailing practice that the distance between the PD module 40 and the LD module 50 is set to 12.7 mm, and the diameter of the PD element 45 and the LD element 55 is usually about 5 mm. In order to protect the PD element 45 and the LD element 55 and

For mechanical coupling of these elements with the associated optical fibers, it is necessary that the PD module 40 and the LD module 50 have a diameter in the range between 6 mm and 8 mm. Accordingly, there is a design limitation for the diameter of an opening 21 in the lower frame to a value in the range between 4.7 mm and 6.7 mm. In this case, the diameter of the opening 21 in the lower frame is in the range between 1.7 mm and 3.7 mm when the average wall thickness of the lower frame 20 is 1.5 mm.
10

)■■■' The optical fiber connector is made using

by pawls 23 of the lower frame 20. The fiber optic module according to the invention has openings 21 in the upper frame in the region of the pawls 23, which are subjected to the highest load during the above-described operation of attachment and detachment. In this case, the diameter of the openings 21 in the upper frame is set to about 3 mm to ensure an average wall thickness of 1.5 mm of the lower frame 20. Since the fiber optic module according to the invention is greatly miniaturized compared to fiber optic modules according to the prior art, the provision of the openings for fastening the fiber optic module, which are arranged at the central part of the lower frame 20 and in the region of the pawls 23, makes a great contribution to the realization of a reliable fiber optic module. In the seventh embodiment of the invention, the 3 mm diameter holes 21 in the lower frame are provided at positions in the lower frame approximately 2.5 mm away from the corresponding projections 26 on the lower frame which are subjected to the largest stress applied to the pawls 23, so that the rigid lower frame 20 with an average wall thickness of 1.5 mm is realized and therefore a highly reliable fiber optic module is provided.

·

9 is a sectional view of a main part of a fiber optic module according to an eighth embodiment of the invention, that is, for facilitating explanation of an arrangement consisting only of the upper frame 10 and the lower frame 20. The upper frame 10 is provided with a thin-walled portion 17 for preventing surface distortions caused by uneven wall thickness of the upper frame 10. The thin-walled portion 17 particularly prevents a reduction in the accuracy of an upper shield housing 17a for housing a PD shield plate 41 and an accuracy of an upper module housing 17b for housing an LD module, each caused by such surface distortions. In the lower frame 20, a thin-walled portion 27 is similarly provided for preventing a deformation of a lower shield housing 27a and a lower module housing 27b, each caused by surface distortions, similarly to the above. In the eighth embodiment of the invention, the creation of these thin-walled regions makes it possible to obtain an upper frame 10 and a lower frame 20 each having an average wall thickness of 1.5 mm and therefore to realize highly reliable upper and lower frames, respectively.

Fig. 10 is a sectional view of a fiber optic module according to a ninth embodiment of the invention. This embodiment differs from the fourth embodiment of Fig. 5 described above in that no self-tapping screws 70 are used, but instead pins 71 integrally fixed to the lower frame 20 by integral molding (or compression molding) are used, and the fiber optic module is fixedly attached to the main board 60 by means of nuts 72 fitting onto the pins 71. In order to allow the upper frame 10 and the PCB 30 to be arranged at roughly predetermined positions, the upper parts of the pins 71 protrude into

Upward direction beyond the contact surface between the upper frame 10 and the lower frame 20. In addition, the pins 71 also protrude downwards beyond the main card 60 to thereby act as guide pins for rough positioning of the fiber optic module during automatic assembly. In addition, a strip 24 extends toward the main card 60 to increase the rigidity of the fiber optic module.

In this way, with the fiber optic module shown in Fig. 10, it is possible not only to eliminate the stresses applied to the respective leads of the PD module 40, the LD module 50 and the contact surfaces of the PCB 30, but also to reduce the requirements for the positional accuracy of the parts such as the terminals for enabling assembly and also to reduce the requirements for the dimensional accuracy of the parts themselves, thereby realizing an inexpensive fiber optic module with high reliability. Further, the pins 71 formed integrally with the lower frame 20 can also be used as reference positions for checking the acceptability of the lower frame 20. Moreover, the LD shield plate 51 and the PC shield plate 41 shown in Fig. 3 above can be formed integrally with the lower frame 20 together with the pins 71, thereby realizing further cost reduction of the fiber optic module.

Of course, the fourth embodiment according to Fig. 5 can be combined with the ninth embodiment according to Fig. 10, whereby substantially the same effects are achieved.

Although in the ninth embodiment of the invention (or in the fourth embodiment) 3 pins 71 (or

If no self-tapping screws 70 were used, only one pin 71 (or one self-tapping screw 70) can be used for the opening in the area of the latches 23 which are subjected to the highest stress when the optical fibre connector is attached or removed, and resin pins extending from the lower frame can be used for the other openings in the area of the cross member 14, thereby achieving essentially the same effects.

Fig. 11 is a perspective view of a fiber optic module (or a combination of an upper frame 10, a lower frame 20 and a PCB 30) according to a tenth embodiment of the invention, the module being provided with a cover 18 for preventing electrostatic damage. After assembling and adjusting the fiber optic module, the cover 18 is mounted on the fiber optic module. Since most of the parts attached to the PCB 30 are covered by the upper frame 10, the lower frame 20 and the cover 18, the possibility of electrostatic damage to the fiber optic module during its handling, which has been a problem in the prior art, can be substantially eliminated.

The material of the cover 18 is not particularly limited by the presence or absence of electrical conductivity. In other words, the material of the cover is not particularly limited from the viewpoint of the resistance of the PCB to electrostatic damage, and a metallic material and a resinous material may be used. In particular, although the cover 18 in this embodiment is made of the same PBT as the upper frame, the electrostatic damage of the PCB 30 possibly caused during handling of the fiber optic module, which has been a problem in the prior art, can be eliminated.

Furthermore, even if the cover 18 is made of an iron alloy from the viewpoint of the resistance of the PCB 30 to electrostatic damage and the electromagnetic shielding of the PD module 40, substantially the same effects can be obtained. Note that even if the cover 18 is made of iron alloy rather than iron, aluminum, aluminum alloy, copper, copper alloy or the like, substantially the same effects can be obtained. It is also apparent that for fixing the cover to the fiber optic module, a method based on fitting the cover to the cross member 14, a snap-on method or a permanent connection can be used, but the invention is not limited to the specific example.

Next, in the fiber optic module of the present invention, the upper surface of the upper frame 10 is formed flat and the bottom plate of the lower frame 20 is also formed flat to increase the rigidity of the lower frame 20, so that an identification mark 90 indicating the place of manufacture of the fiber optic module and a certificate mark 91 indicating which laser safety standard requirements are met can be easily bonded to or permanently bonded to the flat surface of the upper or lower frame. Further, the flat portion of the upper frame 10 (not shown) and the flat portion or a recess (not shown) of the lower frame 20 are each formed as a step or in the form of a recess (not shown) with a depth of about 0.3 mm to enable easy bonding of the identification mark 90 or the certificate mark 91.

It goes without saying that, in order to reduce the costs of the fiber optic module according to the invention, these markings can be present not only in the form of adhesively bonded plaques, but also as markings in the respective frames themselves, for example as engravings.

Fig. 12 is a plan view of a fiber optic module according to an eleventh embodiment of the invention. This embodiment differs from the tenth embodiment shown in Fig. 11 in that a cover plate 18a is formed integrally with the upper frame 10. Another difference between the embodiments shown in Figs. 11 and 12 and the other embodiments is that a cover hole 19 is provided in a cover member 18a so that even after the assembly of the fiber optic module is completed, variable resistors arranged on the PCB can be adjusted through the cover hole 19. In this way, since the cover member 18a is formed integrally with the upper frame 10 during molding or is molded integrally therewith, a fiber optic module having high reliability can be realized in an economical manner. Note that even if the cover hole 19 shown in the eleventh embodiment of the invention is employed in the tenth embodiment shown in Fig. 11, the effects of the invention can be ensured.

Fig. 13A shows an exploded perspective view of a fiber optic module according to a twelfth embodiment of the invention, in which a support plate 73 is used for fastening the fiber optic module to a main PCB 60. The support plate 73 is provided with a fastening part 74 so that the fastening part supports the fastening of the fiber optic module when the fastening part 74 is rotated by an angle of 90°. The fastening of the fiber optic module by means of the fastening parts described above in connection with

The use of the tapping screws 70 described in connection with the fourth embodiment (see Fig. 5) or the pins 71 described in connection with the ninth embodiment (see Fig. 10) is sufficient, but the additional use of the support plate 73 makes it possible to provide a more reliable fiber optic module. When the support plate 73 is made of a metallic material, the support plate 73 can further serve to protect the PD module from electromagnetic noise from the outside and also to shield the electromagnetic noise radiated from the LD module 50 to external elements. ψ It is understood that although the support plate 73 was made of an iron alloy in the twelfth embodiment of the invention, iron, aluminum, an aluminum alloy, gold, copper or a copper alloy can be used as the material for the support plate 73 to achieve substantially the same or equivalent effects. It is further noted that, although the support plate 73 for supporting the fixing of the fiber optic module to the main board 60 was attached from the top in the twelfth embodiment of the invention, the support plate 73 for supporting the fixing of the fiber optic module to the main board 60 may also be attached from the bottom to achieve substantially the same effects.

Fig. 13B shows a perspective view of the fiber optic module according to the twelfth embodiment of the invention in the assembled state. As shown in Fig. 13B, the fiber optic module including the PCB 30, the upper frame 10, the lower frame 20 and the other components is assembled by first attaching it to the main board 60 with the tapping screws 70 and other fastening means as shown in Fig. 5 and then attaching the support plate 73 having fastening wings 74 at both ends. The fastening wings 74 are used to attach the fiber optic module.

The optical module arrangement on the main card 60 is twisted by approximately 90°.

Fig. 14 is a perspective view of a fiber optic module according to a thirteenth embodiment of the invention. In order to prevent dust from entering the LD module and the PD module in the non-operational state (during storage, transportation, etc.) of the fiber optic module (i.e., an assembled combination of the upper frame 10, the lower frame 20, and the PCB 30), a module cap 80 is attached to the fiber optic module.

Next, the module cap 80 will be described in detail with reference to Fig. 15 which is a plan view of the fiber optic module according to the thirteenth embodiment of the invention. To explain the module cap 80 in detail, parts of the LD module 50 are shown in section. In Fig. 15, a PD element 45 is fixed to the PD module 40 by a permanent connection (e.g., by welding) or the like, and an LD element 55 is fixed to the LD module 50 by welding (or other permanent connection) or the like, so that the PD module 40 and the LD module 50 are physically or mechanically detachably fixed to the lower frame 20 and electrically connected to the PCB 30 by PD lines 47 and LD lines 57, respectively. The module cap 80, which is arranged so that it does not contact the latches 23 of the lower frame 20, is provided with cap projections 85 for holding the module cap 80 on the fiber optic module and also with a handle bar 87 for easy attachment and removal of the module cap 80 on or from the fiber optic module. When the module cap 80 is attached to the fiber optic module, end surfaces 82 of the cap do not contact an annular stop surface 56 of the LD module 50 and a module stop surface 84 of the module cap 80 contacts an LD module end surface 53 of the LD module 50 to thereby prevent the ingress of dust into an LD

·

· ■

·

module opening 52. Moreover, the diameter of a cap projection 83 is designed to be sufficiently smaller than the diameter of the LD module opening 52 so that the module cap 80 can be easily attached and removed while preventing the generation of dust or foreign matter in the opening 52 during attachment and removal of the module cap 80.

In Fig. 16, a perspective view of the module cap 80 of the fiber optic module according to the thirteenth embodiment is shown for clarity. Elastic members 86 extending from the module stop surfaces 84 to the cap end surfaces 82 for preventing dust from entering the LD module 50 and the PD module 40 are elastically deformed with the cap projections 85 so that the module cap 80 is held on the fiber optic module. The module cap 80 has a cap opening 81 for checking its acceptability. The material of the module cap 80 is selected from comparatively soft polyethylene, but the invention is not limited to the specific example and any material can be used as long as the material is a resin.

As explained above, according to the fiber optic module of the present invention, the following features 1) to 6) can be obtained by providing a compact fiber optic module having a width of 25.4 mm, a length of 50.8 mm and a height of 11.5 mm and equipped with indispensable minimum functions.

1) Since the transmission of electrical signals is carried out in the form of serial data, the number of signal lines can be reduced to as few as 22, the terminal arrangement can be made small, and furthermore, the need to provide semiconductor ICs for serial/parallel conversion can be eliminated. Therefore,

This invention not only follows the current trend of rapid miniaturization of processing computers, but also significantly increases the design flexibility in the manufacture of main cards in systems. 5

2) The fixing of the fiber optic module to the main board is achieved by means of self-tapping screws passed through respective holes in the main board according to the present invention, and only three small holes are required as holes in the main board. Therefore, the design flexibility of the main board can be greatly increased for the system manufacturers. Furthermore, since the fiber optic module according to the present invention is designed so that the force loads caused when the optical fiber is attached and removed act on all the self-tapping screws, damage to the connections of the electric lines can be completely eliminated and therefore a highly reliable fiber optic module can be realized.

In addition, since the invention is designed so that the three openings accommodate variations within the dimensional accuracies of the parts, stresses applied to the lines of the respective modules can be eliminated and it becomes unnecessary to increase the accuracy of the parts and to control the parts (such as checking the acceptability of the parts), thereby realizing an inexpensive fiber optic module.

3) When the terminal of the fiber optic module of the present invention is formed in an external mounting manner such as a structure on a main surface of a printed circuit board, manual work including direct connection of the signal line to the main board by soldering can be eliminated and therefore the cost of the fiber optic module can be kept low.

4) If the printed circuit board is on its front

is provided with holding means for holding the circuit board by means of a snap-fitting mechanism of the upper and lower frames and is provided on its rear side with holding means for holding the circuit board on the upper frame having a very weak elasticity, warping of the circuit board can be prevented and therefore the circuit board can be manufactured with a remarkably high reliability. Furthermore, the requirement of a sufficiently large circuit board holding length L, which had to be long enough in the prior art, can be eliminated and therefore a compact fiber optic module can be realized.

5) The circuit board is covered with the upper frame, the lower frame and/or the cover, and therefore the handling of the fiber optic module for assembly or inspection can be simplified. The assembly and inspection efficiency of the fiber optic module can be increased, and the fiber optic module can be manufactured inexpensively with high reliability while avoiding electrostatic destruction of the circuit board.

6. If an inexpensive module cap with a simple shape is attached to the fiber optic module, the cap can prevent dust from entering the fiber optic module during long-term storage, an unusable connection between the optical fiber and the module can be avoided, and therefore the fiber optic module can be manufactured with a remarkably high operational reliability.

In this way, this invention brings with it a high degree of practical advantage.

Claims (63)

1. Fiber optic module comprising:
a connector ( 32 ) for connecting the fiber optic module to a main card ( 60 )
an electrical LD signal converter device ( 55 ) for converting serial data received from the main card into an electrical LD signal for a laser diode (LD),
an LD module ( 50 ) for converting the electrical LD signal into an optical LD signal,
a PD module ( 40 ) for converting an optical photodiode (PD) signal into an electrical PD signal,
a PD electrical signal converter ( 45 ) for converting the PD electrical signal into serial PD data,
a circuit board ( 30 ) for carrying the connector, the LD electrical signal conversion device, the LD module and the PD module thereon and
a first frame ( 10 ) and a second frame ( 20 ) for holding the circuit board, the LD module and the PD module,
The connection is designed like an external attachment. 2. A fiber optic module according to claim 1, wherein leads of the LD module ( 50 ) and the PD module ( 40 ) are connected to the surface of the circuit board ( 30 ) on which the connector ( 32 ) is mounted. 3. A fiber optic module according to claim 1 or 2, further comprising a variable LD resistor ( 34 ) for adjusting a drive current of the LD module ( 50 ), and wherein the variable LD resistor is mounted on a surface of the circuit board opposite to the surface having the terminal thereon. 4. A fiber optic module according to any one of claims 1 to 3, further comprising a variable PD resistor ( 34 ) for detecting a signal of the PD module ( 40 ), wherein the variable PD resistor is mounted on a surface of the circuit board opposite the surface having the terminal thereon. 5. Fiber optic module according to one of claims 1 to 4, wherein the converter device ( 45 ) for the electrical PD signal contains a plurality of semiconductor IDs. 6. Fiber optic module according to one of claims 1 to 5, wherein the circuit card ( 30 ) has a width of 17 mm to 25.4 mm and a length of 30 mm to 50 mm. 7. Fiber optic module, in particular according to one of the preceding claims, comprising:
a connector ( 32 ) for connecting the fiber optic module to a main card ( 60 ),
an electrical LD signal converter device ( 55 ) for converting serial data received from the main card into an electrical LD signal for a laser diode (LD),
an LD module ( 50 ) for converting the electrical LD signal into an optical LD signal,
a PD module ( 40 ) for converting an optical photodiode (PD) signal into an electrical PD signal,
a PD electrical signal converter ( 45 ) for converting the PD electrical signal into serial PD data,
a circuit board ( 30 ) for carrying the connector, the LD electrical signal conversion device, the LD module and the PD module thereon and
a first frame ( 10 ) and a second frame ( 20 ) for holding the circuit board, the LD module and the PD module,
wherein the external dimensions of the fiber optic module have a width of 19 mm to 25.4 mm, a length of 45 mm to 65 mm and a height of 9 mm to 25.4 mm. 8. The fiber optic module of claim 7, further comprising a housing that includes the first frame ( 10 ) and the second frame ( 20 ) and forms an outer housing. 9. A fiber optic module according to claim 7, wherein the first frame ( 10 ) and the second frame ( 20 ) are made of a resin material. 10. Fiber optic module, in particular according to one of the preceding claims, comprising:
a connector ( 32 ) for connecting the fiber optic module to a main card ( 60 )
an electrical LD signal converter device ( 55 ) for converting serial data received from the main card into an electrical LD signal for a laser diode (LD),
an LD module ( 50 ) for converting the electrical LD signal into an optical LD signal,
a PD module ( 40 ) for converting an optical photodiode (PD) signal into an electrical PD signal, an electrical PD signal converter ( 45 ) for converting the electrical PD signal into serial PD data,
a circuit board ( 30 ) for carrying the connection of the LD electrical signal converter device, the LD module and the PD module thereon and
a first frame ( 10 ) and a second frame ( 20 ) for holding the circuit board, the LD module and the PD module,
wherein the module comprises attachment means for attaching the first frame ( 10 ) and the second frame ( 20 ) to the main card ( 60 ). 11. A fiber optic module according to claim 10, wherein the attachment means includes a screw ( 70 ). 12. The fiber optic module of claim 11, further comprising first frame openings ( 11 ) provided in the first frame ( 10 ), second frame openings ( 21 ) provided in the second frame ( 20 ), circuit card openings ( 32 ) provided in the circuit board, and main card openings ( 61 ) provided in the main card, and wherein the screws are inserted into the first frame openings, the second frame openings, the circuit card openings, and the main card openings to fasten the first frame, the second frame, the circuit board, and the main card to each other. 13. A fiber optic module according to claim 12, wherein the first frame openings ( 11 ) are smaller than the second frame openings ( 21 ) and the circuit card openings ( 32 ) and the main card openings ( 61 ) have substantially the same diameter as the second frame openings. 14. Fiber optic module according to one of claims 11 to 13 , wherein the screws ( 70 ) have an effective diameter of 1.3 mm or more. 15. Fiber optic module according to one of claims 12 to 14, wherein three first frame openings ( 11 ) are provided in the first frame ( 10 ) and the first frame openings are arranged at the corners of a substantially isosceles triangle. 16. Fiber optic module according to one of claims 12 to 15, wherein the first frame openings ( 11 ) can also be used as reference holes for checking the first frame and the second frame openings ( 21 ) can also be used as reference holes for checking the second frame. 17. Fiber optic module according to one of claims 11 to 16, wherein the screws are self-tapping screws. 19. Fiber optic module according to claim 18, wherein only pins ( 71 ) protruding from the second frame ( 10 or 20 ) are used as attachment means. 20. The fiber optic module of claim 19, further comprising first frame openings ( 11 ) provided in the first frame ( 10 ), circuit card openings ( 32 ) provided in the circuit card, and main card openings ( 61 ) provided in the main card, and wherein screws are inserted into the first frame openings, the circuit card openings, and the main card openings for securing the first frame, the circuit card, and the main card to each other. 21. A fiber optic module according to claim 20, wherein the first frame openings ( 11 ) have a larger diameter than the pin ( 71 ) and the circuit card openings ( 32 ) and the main card openings ( 61 ) have substantially the same diameter as the first frame openings. 22. Fiber optic module according to one of claims 18 to 21, wherein the pin ( 71 ) has a diameter of 1.3 mm or more. 23. Fiber optic module according to one of claims 18 to 22, wherein the pin ( 71 ) is made of a metallic material. 24. A fiber optic module according to any one of claims 18 to 23, wherein the pin ( 71 ) is formed integrally with the second frame ( 20 ) or is press-fitted therein. 25. Fiber optic module according to one of claims 18 to 24, wherein three first frame openings ( 11 ) are provided in the first frame ( 10 ) and the first frame openings are arranged from the corners of a substantially equilateral triangle. 26. Fiber optic module according to one of claims 1ß to 25, wherein the first frame openings ( 11 or 21 ) can also be used as reference holes for checking the first frame and the pins ( 71 ) can also be used as reference holes for checking the second frame. 27. Fiber optic module, in particular according to one of the preceding claims, comprising:
a connector ( 32 ) for connecting the fiber optic module to a main card ( 60 ),
an electrical LD signal converter device ( 55 ) for converting serial data received from the main card into an electrical LD signal for a laser diode (LD),
an LD module ( 50 ) for converting the electrical LD signal into an optical LD signal,
a PD module ( 40 ) for converting an optical photodiode (PD) signal into an electrical PD signal,
a PD electrical signal converter ( 45 ) for converting the PD electrical signal into serial PD data,
a circuit board ( 30 ) for carrying the connector, the LD electrical signal conversion device, the LD module and the PD module thereon and
a first frame ( 10 ) and a second frame ( 20 ) for holding the circuit board, the LD module and the PD module,
wherein the circuit board is detachably attached to the first frame ( 10 ) and/or the second frame ( 20 ). 28. The fiber optic module of claim 27, wherein the means for releasably securing is a snap-on fastening mechanism. 29. A fiber optic module according to claim 27 or 28, wherein the circuit board is releasably secured at one end thereof by the snap-on fastening mechanism. 30. Fiber optic module according to one of claims 27 to 29, wherein an elastic cross member is provided on the first frame and/or on the second frame and the circuit board is detachably attached to the other frame by means of the cross member. 31. A fiber optic module according to any one of claims 27 to 30, wherein the circuit board is releasably secured at its front part with a snap-on fastening mechanism and is releasably secured at its rear part to the other frame with a resilient cross member. 32. Fiber optic module, in particular according to one of the preceding claims, comprising:
a connector ( 32 ) for connecting the fiber optic module to a main card ( 60 )
an electrical LD signal converter device ( 55 ) for converting serial data received from the main card into an electrical LD signal for a laser diode (LD),
an LD module ( 50 ) for converting the electrical LD signal into an optical LD signal,
a PD module ( 40 ) for converting an optical photodiode (PD) signal into an electrical PD signal,
a PD electrical signal converter ( 45 ) for converting the PD electrical signal into serial PD data,
a circuit board ( 30 ) for carrying the connector, the LD electrical signal conversion device, the LD module and the PD module thereon and
a first frame ( 10 ) and a second frame ( 20 ) for holding the circuit board, the LD module and the PD module,
the module further comprising a carrier device for securing the first frame and the second frame and the main card at their outer surfaces attractable together. 33. A fiber optic module according to claim 32, wherein the support means is formed from a metal plate. 34. Fiber optic module according to claim 33, in which the metal plate is provided with recesses in the region of its two ends and is rotatable in the region of the recesses to ensure a tight fixing of the metal plate. 35. Fiber optic module according to one of claims 32 to 34, wherein the carrier device is arranged at a location opposite the LD module and the PD module. 36. Fiber optic module, in particular according to one of the preceding claims, comprising:
a connector ( 32 ) for connecting the fiber optic module to a main card ( 60 ),
an electrical LD signal converter device ( 55 ) for converting serial data received from the main card into an electrical LD signal for a laser diode (LD),
an LD module ( 50 ) for converting the electrical LD signal into an optical LD signal,
a PD module ( 40 ) for converting an optical photodiode (PD) signal into an electrical PD signal,
a PD electrical signal converter ( 45 ) for converting the PD electrical signal into serial PD data,
a circuit board ( 30 ) for carrying the connection of the LD electrical signal converter device, the LD module and the PD module thereon and
a first frame ( 10 ) and a second frame ( 20 ) for holding the circuit board, the LD module and the PD module,
the module further comprising a cover for covering an externally exposed portion of the circuit board therewith. 37. A fiber optic module according to claim 36, wherein the cover is formed of a resin material. 38. A fiber optic module according to claim 36, wherein the cover is formed from a metallic material. 39. Fiber optic module according to one of claims 36 to 38, wherein the cover is formed in the shape of the first frame. 40. Fiber optic module according to one of claims 36 to 39, wherein the cover is provided with an opening. 41. Fiber optic module, in particular according to one of the preceding claims, comprising:
a connector ( 32 ) for connecting the fiber optic module to a main card ( 60 ),
an electrical LD signal converter device ( 55 ) for converting serial data received from the main card into an electrical LD signal for a laser diode (LD),
an LD module ( 50 ) for converting the electrical LD signal into an optical LD signal,
a PD module ( 40 ) for converting an optical photodiode (PD) signal into an electrical PD signal,
a PD electrical signal converter ( 45 ) for converting the PD electrical signal into serial PD data,
a circuit board ( 30 ) for carrying the connector, the LD electrical signal conversion device, the LD module and the PD module thereon,
a first frame ( 10 ) and a second frame ( 20 ) for holding the circuit board, the LD module and the PD module,
the module further comprising indication elements ( 91 , 90 ) for indicating a security certificate and the place of manufacture, which are provided on the first and the second frame respectively. 42. A fiber optic module according to claim 41, wherein the indication element ( 91 or 90 ) provided on the first frame is opposite to the indication element ( 91 or 90 ) provided on the second frame. 43. A fiber optic module according to claim 42, wherein the first frame and the second frame each have a recess and the indicator elements are mounted in the recesses. 44. Fiber optic module according to one of claims 41 to 43, wherein the indication elements are seal markings. 45. A fiber optic module according to any one of claims 41 to 43, wherein the indicator elements are formed integrally with the first frame or the second frame. 46. Fiber optic module, in particular according to one of the preceding claims, comprising:
a connector ( 32 ) for connecting the fiber optic module to a main card ( 60 ),
an electrical LD signal converter device ( 55 ) for converting serial data received from the main card into an electrical LD signal for a laser diode (LD),
an LD module ( 50 ) for converting the electrical LD signal into an optical LD signal,
a PD module ( 40 ) for converting an optical photodiode (PD) signal into an electrical PD signal,
a PD electrical signal converter ( 45 ) for converting the PD electrical signal into serial PD data,
a circuit board ( 30 ) for carrying the connector, the LD electrical signal conversion device, the LD module and the PD module thereon and
a first frame ( 10 ) and a second frame ( 20 ) for housing the circuit board, the LD module and the PD module,
where the data transmission rate of the optical signal is 130 Mbit/s or more. 47. A fiber optic module according to claim 46, wherein the data transmission rate of the optical signal is 200 Mbit/s or more. 48. A fiber optic module according to claim 46, wherein the data transmission rate of the optical signal is 500 Mbit/s or more. 49. A fiber optic module according to claim 46, wherein the data transmission rate of the optical signal is 1000 Mbit/s or more. 50. Fiber optic module, in particular according to one of the preceding claims, comprising:
a connector ( 32 ) for connecting the fiber optic module to a main card ( 60 ),
an electrical LD signal converter device ( 55 ) for converting serial data received from the main card into an electrical LD signal for a laser diode (LD),
an LD module ( 50 ) for converting the electrical LD signal into an optical LD signal,
a PD module ( 40 ) for converting an optical photodiode (PD) signal into an electrical PD signal,
a PD electrical signal converter ( 45 ) for converting the PD electrical signal into serial PD data,
a circuit board ( 30 ) for carrying the connector, the LD electrical signal conversion device, the LD module and the PD module thereon and
a first frame ( 10 ) and a second frame ( 20 ) for holding the circuit board, the LD module and the PD module,
wherein the fiber optic module further includes a module cap ( 80 ) to be inserted into light outlet and light inlet openings defined by the first frame and the second frame along a light inlet and outlet direction, respectively. 51. Fiber optic module according to claim 50, wherein the module cap ( 80 ) has a cap fastening device engaging in a part of the first frame and in a part of the second frame and attachable to the first frame and/or the second frame. 52. Fiber optic module, in particular according to one of the preceding claims, comprising:
a connector ( 32 ) for connecting the fiber optic module to a main card ( 60 ),
an electrical LD signal converter device ( 55 ) for converting serial data received from the main card into an electrical LD signal for a laser diode (LD),
an LD module ( 50 ) for converting the electrical LD signal into an optical LD signal,
a PD module ( 40 ) for converting an optical photodiode (PD) signal into an electrical PD signal,
a PD electrical signal converter ( 45 ) for converting the PD electrical signal into serial PD data,
a circuit board ( 30 ) for carrying the connector, the LD electrical signal converter, the LD module and the PD module thereon, and
a first frame ( 10 ) and a second frame ( 20 ) for holding the circuit board, the LD module and the PD module,
wherein the fiber optic module includes a shielding member for shielding the LD module and/or the PD module. 53. A fiber optic module according to claim 52, wherein a shield plate ( 51 ) is provided for exclusive use for the LD module and a shield plate ( 41 ) is provided for exclusive use for the PD module. 54. Fiber optic module according to claim 52 or 53, wherein the first frame and/or the second frame is integrally provided with a shielding plate. 55. Fiber optic module, in particular according to one of the preceding claims, comprising:
a connector ( 32 ) for connecting the fiber optic module to a main card ( 60 ),
an electrical LD signal converter device ( 55 ) for converting serial data received from the main card into an electrical LD signal for a laser diode (LD),
an LD module ( 50 ) for converting the electrical LD signal into an optical LD signal,
a PD module ( 40 ) for converting an optical photodiode (PD) signal into an electrical PD signal,
a PD electrical signal converter ( 45 ) for converting the PD electrical signal into serial PD data,
a circuit board ( 30 ) for carrying the connector, the LD electrical signal conversion device, the LD module and the PD module thereon and
a first frame ( 10 ) and a second frame ( 20 ) for holding the circuit board, the LD module and the PD module,
wherein elastic latches ( 23 ) which can be brought into contact with a connector for an optical fibre are provided on the first frame and/or on the second frame, and the latches are provided at their roots with projections ( 26 ) extending towards the other frame. 56. Fiber optic module according to claim 55, wherein second projections ( 16 ) for protecting the first projections ( 26 ) are provided on the frame opposite the frame provided with the first projections ( 26 ). 57. A fiber optic module according to claim 55, wherein the first frame ( 10 ), the second frame ( 20 ) and the pawls ( 23 ) are made of a resin material. 58. Fiber optic module comprising:
a connector ( 38 ) for connecting the fiber optic module to a main board ( 60 ) of a computer,
a first semiconductor integrated circuit ( 37 ) for converting first parallel data supplied by the main card into first serial data for a laser diode,
a second semiconductor integrated circuit ( 33 ) for converting the first serial data for the laser diode converted by the first semiconductor integrated circuit into a first electrical signal,
a laser diode (LD) module ( 50 ) containing a laser diode for converting the first electrical signal for the laser diode into a first optical signal of the laser diode,
a photodiode (PD) module ( 40 ) containing a photodiode for converting a second optical signal received from the photodiode into a second electrical signal of the photodiode,
a third semiconductor integrated circuit ( 35 ) for converting the second electrical signal of the photodiode into second serial data of the photodiode,
a fourth semiconductor integrated circuit ( 36 ) for converting the second serial data of the photodiode converted by the third semiconductor integrated circuit into second parallel data,
a circuit board ( 30 ) for providing the connection of the first semiconductor integrated circuit, the second semiconductor integrated circuit, the third semiconductor integrated circuit and the fourth semiconductor integrated circuit,
a first shielding plate ( 51 ) for electrically shielding the LD module,
a second shielding plate ( 41 ) for electrically shielding the PD module,
a first frame ( 10 ) for holding the circuit board, the LD module and the PD module and
a second frame ( 20 ) cooperating with the first frame for holding the circuit board, the LD module and the PD module. 59. Fiber optic module comprising a connector for connection to a main card,
a laser diode driver circuit for converting serial data received via the connector from the main card into an electrical laser diode signal for a laser diode,
a laser diode module for converting the electrical laser diode signal into an optical laser diode signal,
a photodiode module for converting an optical photodiode signal into an electrical photodiode signal,
an integrated semiconductor circuit for converting the electrical photodiode signal into serial photodiode data, the serial photodiode data being transmitted to the main card via the connector,
a circuit board carrying the connector, the laser diode driver circuit, the laser diode module, the photodiode module and the semiconductor integrated circuit, and
a frame for holding the circuit board, the laser diode module and the photodiode module. 60. Fiber optic module according to claim 1, wherein the connection is designed as an SMT component or in the manner of an external attachment. 61. A fiber optic module according to any preceding claim, wherein the module further comprises indicia on the frame for indicating a safety certificate and/or the place of manufacture. 62. Fiber optic module according to one of the preceding claims, wherein a data transmission speed of the optical signal is 130 Mbits/s or more. 63. Fiber optic module according to one of the preceding claims, wherein a data transmission speed of the optical signal is 1000 Mbits/s or more. 64. A fiber optic module according to any preceding claim, wherein the fiber optic module further comprises a module cap insertable into light outlet and light inlet openings defined by the frame along a light inlet and light outlet direction.