JP4454233B2 - Optical package and optical module using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technology related to mounting of a surface-emitting optical semiconductor element such as a surface-emitting laser (hereinafter, VCSEL), a PIN photodiode (hereinafter, PIN-PD), an avalanche photodiode (hereinafter, APD), For example, it is suitable for mounting such a surface-emitting / emitting optical semiconductor element, or mounting an electronic component for operating it, and is excellent in mass productivity, small in size, excellent in high-frequency characteristics and highly reliable. The present invention relates to an optical package that can be assembled and an optical module using the same.
[0002]
[Prior art]
In recent years, large-capacity optical fiber communication has become widespread and developed in the fields of public communication and local area communication (LAN). As a result, transmission speed is increased, and high-speed optical transmission using an optical fiber is required. In addition to optical transmission over a distance of several kilometers to several hundred kilometers that has been conventionally used, very short distance (Very Short Reach) The importance of VSR) optical transmission and applications called Gigabit Ethernet (R) (GbE) are increasing. In these VSR and GbE applications, an optical transmission rate of 10 gigabits per second is being required, and in such transmission, an unspecified number and a wide variety of uses are assumed. Industrialization and improvement of mass productivity are considered industrially important.
[0003]
In the above optical communication system, a 0.85 μm band VCSEL is frequently used as a new optical semiconductor device which is excellent in mass productivity, stable in characteristics and capable of high-speed optical transmission. Also, VCSEL elements in the 1.31 μm band and 1.55 μm band are under development and are expected to be commercialized.
[0004]
In the light receiving element, a PIN-PD, and a surface light receiving element such as an APD are used to electrically convert a high-speed optical signal as in the conventional case.
[0005]
The inventors attach an optical waveguide that is optically connected to a planar optical semiconductor element to a substrate on which a VCSEL element is disposed and wiring for energizing the VCSEL element is formed. The surface excluding the installation surface and the back surface thereof is fixed to an external circuit board on which external wiring for energizing the planar optical semiconductor element is formed, and the external wiring formed on the external circuit board and the base are formed. There has already been proposed an optical module that can be electrically connected to wiring (see Patent Document 1). In this proposal, the optical module can be configured simply, the assembly is simple, and good optical connection can be efficiently performed.
[0006]
In a LAN or the like using Gigabit Ethernet (R), for example, an optical transceiver in which a transmitter and a receiver are packaged and mounted in one is common, and the size is also standardized (see Patent Document 2). reference).
[0007]
In recent years, in order to reduce the size of the entire apparatus, downsizing of an optical transceiver has been promoted, and a form called SFF (Small Form Factor), which is about half the size of the conventional one, has been changed.
[0008]
Conventionally, these optical semiconductor elements are generally mounted in a conventional optical package as shown in FIG. The conventional optical package shown in FIG. 11 is called a TO-CAN package, and is an optical semiconductor from the outside through a cylindrical stem 30 made of metal, a cylindrical glass feedthrough 33 provided on the stem 30, and a glass feedthrough 33. A cylindrical lead pin 32 for energizing the element and a cap 31 attached to the stem 30 for hermetically sealing the optical semiconductor element. The VCSEL element 40 that is an optical semiconductor element is mounted on the stem 30 and is electrically connected to the lead pin 32 by a gold wire 41. Thereafter, the cap 31 is fixed to the stem 30 and sealed to complete the VCSEL module. A transparent window 31a is attached to the top of the cap 31, and the VCSEL element 40 is optically connected to an external optical waveguide through the transparent window 31a. The VCSEL module is mounted and fixed on an external electronic circuit board.
[0009]
[Patent Document 1]
Japanese Patent Application No. 2002-204682
[Patent Document 2]
JP 2000-214351 A
[0010]
[Problems to be solved by the invention]
However, in the optical module using the TO-CAN package, when the optical module is fixed to the electronic circuit board on which the electronic circuit is mounted with the lead pins 32, the lead pins 32 are aerial wiring between the package and the electronic circuit board. Therefore, the discontinuity of the characteristic impedance of the wiring is large and the high frequency characteristics are deteriorated.
[0011]
In order to solve this problem, it may be possible to mount the lead pin 32 on the electronic circuit board by shortening the lead pin 32 as much as possible so that the lead pin 32 is not exposed to the air. However, it is difficult to ensure reliability for a long period of time, and the high frequency characteristics are not stable due to variations in the length of the lead pins 32 and variations in the amount of solder when the optical module is mounted and fixed, resulting in poor mass productivity. The TO-CAN package is standardized in size, for example, φ5.6 mm. However, when the size is further reduced, the graphed through 33 and the glass through thru 33 required to keep the characteristic impedance of the glass feedthrough 33 constant. It is necessary to reduce the variation in the size of the lead pin 32 and to manage it more strictly, making it difficult to manufacture.
[0012]
Further, since the signal line is bent at the connection portion between the lead pin 32 and the gold wire 41 in the package, the characteristics of the package alone are not sufficient. 12 and 13 show frequency response characteristics of electrical wiring of a single TO-CAN package. That is, the input end of the lead pin 31 does not protrude from the stem 30 at all, the output end is taken as a terminal to be input to the VCSEL element 9 at one end of the gold wire 41, and the signal line model is configured by the lead pin 31 and the gold wire 41. Shows the reflection characteristics (FIG. 12) and transmission characteristics (FIG. 13) of the frequency response. Also in the characteristics indicated by the broken line, which is a case where the resistance is terminated in the vicinity of the VCSEL element 9 so as to match the characteristic impedance of the glass feedthrough 33, the reflection of the signal at a high frequency is large as shown in FIG. As shown in the figure, since almost no signal is transmitted, it is difficult to use for signal transmission of 10 Gbps, for example.
[0013]
Further, even when a substrate such as a microstrip line whose characteristic impedance is controlled is used instead of the gold wire 41, there is a problem in that the high-frequency signal is deteriorated at the bent portion in the connection portion between the lead pin 32 and the microstrip line substrate. is there.
[0014]
Further, since the lead pins 32 are arranged concentrically from the center of the package, in order to mount on the electronic circuit board, the pins are bent in the middle of the lead pins 32, holes are made in the electronic circuit board, and the lead pins 32 are inserted. It was a structure with poor mass productivity that was not suitable for electronic component mounting processes, such as soldering.
[0015]
Therefore, the present invention has been proposed in view of the above-mentioned problems, and is particularly suitable for mounting a surface-emitting light-emitting type optical semiconductor element, and is excellent in mass productivity, small in size, excellent in high-frequency characteristics, and highly reliable. It is an object to provide a package and an optical module using the package.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, an optical package of the present invention is a base on which an optical semiconductor element is mounted on a surface, and is a laminated structure comprising a plurality of dielectric layers. A substrate having a mounting surface for mounting on a side end portion of the external circuit board, and a castellation provided on the mounting surface When,
Said Conductor pattern formed on the front and back of the laminated structure A conductor pattern which inputs and outputs electrical signals to and from the optical semiconductor element from the conductor pattern on the surface side. When,
Said Formed inside the laminated structure , Consists of conductor pattern and through-hole conductor The distance from the center to the center of the through-hole conductors formed in the dielectric layers adjacent to each other is gradually narrowed as the conductor pattern on the back surface side approaches the conductor pattern on the front surface side. A stepped conductor,
On the mounting surface External circuit board Connect with external wiring above Lead conductor for A lead conductor having one end accommodated in the castellation and connected to the conductor pattern on the back side and electrically connected to the conductor pattern on the front side via the stepped conductor. When , The Equipped It is characterized by that.
[0017]
Also, in the above-mentioned configuration, R Fit Formed in the dielectric layer Of the through-hole conductor From center to center The interval is set to ¼ or less of the wavelength of the electrical signal.
[0018]
Further, the stepped conductor is constituted by a coplanar line, and the interval between the adjacent through-hole conductors is gradually narrowed as the conductor pattern formed on the surface of the laminated structure is approached.
[0019]
Within the castellation, The lead conductor is held on at least three surfaces.
[0020]
Further, a capacitor is formed in a part of the laminated structure.
[0021]
Further, an electronic element for driving the optical semiconductor element is mounted on the front surface or the back surface of the laminated structure.
[0022]
In addition, a radiating fin is attached to a surface excluding the surface of the laminated structure.
[0023]
Also, a conductor pattern for mounting the electronic element or the optical semiconductor element As a part of the heat dissipation, provide a heat dissipation conductor pattern. The radiating fin is connected.
[0024]
The optical module of the present invention is formed by mounting at least an optical semiconductor element on any of the above optical packages. Specifically, only an optical semiconductor element or an optical semiconductor element and an electronic element are mounted on the optical package, an optical waveguide is fixed above the optical semiconductor element, and the side surface of the recess and the lead conductor are connected to external electrons. It is fixed to the side edge of the circuit board, converts the electric signal on the external electronic circuit board into an optical signal, and takes out the optical signal to the side edge through the waveguide, or toward the side edge. The optical signal guided through the waveguide is converted into an electrical signal, and the electrical signal is taken out on the external electronic circuit board.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an optical package and an optical module using the same according to the present invention will be described below in detail with reference to the drawings schematically showing the embodiments.
[0026]
1 to 4 are views for explaining an optical package P1 according to the present invention. FIG. 1 is a perspective view of the front side of the optical package P1, FIG. 2 is a perspective view of the back side of the optical package P1, and FIG. FIG. 4 is a perspective view showing an internal wiring structure in FIG. 3. 5 and 6 are views for explaining a state where the VCSEL is mounted on the optical package P1, FIG. 5 is a perspective view of the front side of the optical package P1, and FIG. 6 is a cross-sectional view of FIG. FIG. 7 is a cross-sectional view (a conductor pattern for electric wiring and a through-hole conductor are omitted from the drawing) for explaining a state in which a radiation fin is attached to the optical package P1. FIG. 8 is a perspective view for explaining the optical module M1 according to the present invention. FIG. 9 is a side view for explaining a state in which the optical transceiver assembly A1 is configured by mounting the light M1 on the external electronic circuit board together with the receiving module and other electronic components.
[0027]
The optical package P1 of the present invention has a base 1 having a laminated structure composed of a plurality of dielectric layers, a conductor pattern 11 formed on the surface 16 of the base 1, and a conductor pattern 12 (12a, 12b formed on the inner layer of the base 1). 12c) and the conductor pattern 13 formed in the recess 18 on the back surface of the substrate, the through-hole conductor 10 connecting them, and the mounting surface 19 (the side surface of the recess 18 on the back surface of the substrate) of the optical module to be described later. An attached lead conductor is composed of an external electrode lead 14 held on at least three surfaces and a metal fitting 2 joined to the surface 16. A VCSEL element 9 and other VCSELs are formed in a cavity 15 formed on the surface 16. A driver 23 or the like is mounted so that the gold ribbon 20 can be electrically connected to one end of the conductor pattern 10. Here, the conductor pattern 12 and the through-hole conductor 10 constitute a stepped conductor, and the external electrode lead 14 and the conductor pattern 11 formed on the surface of the laminated structure are electrically connected via the stepped conductor. In this way, an electrical signal can be inputted / outputted from the conductor pattern 11 formed on the surface of the laminated structure to the optical semiconductor element mounted on the surface of the substrate 1.
[0028]
Further, the optical module M1 of the present invention has a VCSEL element 9 and other VCSEL driver 23 mounted in the cavity 15 of the optical package P1, and is electrically connected to one end of the conductor pattern 10 of the optical package P1 by the gold ribbon 20, 16, an optical waveguide optically connected to the VCSEL element 9 (mainly an optical fiber 22 and a ferrule 21 accommodating the same, a lens or the like (not shown)), a metal fitting 2 as a support, a transparent window fitting 3, The mounting surface 19 of the optical module mounted on the external electronic circuit board is fixed to the mounting surface of the mounting substrate 8, and is mounted by the first metal protection body 4 and the second metal protection body 5. The external wiring formed on the external electrode and the external electrode lead 14 can be electrically connected.
[0029]
First, the configuration of the optical package P1 will be described in detail.
[0030]
The electrical wiring of the optical package P1 includes a high-frequency signal line used for optical modulation of the VCSEL element 9 and a DC line used for bias voltage application of the VCSEL element 9, and each includes a through-hole conductor 10, conductor patterns 11, 12, 13 and an external part. A part of the electrode lead 14 is used.
[0031]
Of the electrical wiring of the optical package P1, the high-frequency signal line sandwiches the signal conductors 10c, 11c, 12c, 13c, and 14c between the ground conductors 10a, 11a, 12a, 13a, and 14a and the ground conductors 10b, 11b, 12b, 13b, and 14b. To form a coplanar electrode. The high-frequency signal line adjusts the size of the signal conductor and the distance between the signal conductor and the ground conductor so as to match the characteristic impedance (for example, 25Ω or 50Ω) of the external wiring formed on the external circuit board.
[0032]
In the mounting method shown here, the VCSEL element 9 is mounted so as to transmit a high-frequency signal incident from the back of the back surface thereof to an electrode formed on the surface in order to reduce the size, so that the high-frequency signal line has a plurality of bent portions. is required. However, this bent portion causes deterioration in the group delay characteristics in the reflection characteristics, transmission characteristics, and transmission characteristics, which are the transmission characteristics of the high-frequency signal, for reasons such as impedance mismatch.
[0033]
Therefore, the conductor pattern 12 and the through-hole conductor 10 are arranged in a step shape, and the conductor pattern 11 and the conductor pattern 13 are smoothly connected. Further, the distance between the signal conductor and the ground conductor is made from the conductor pattern 13 toward the conductor pattern 11 so that an electrode (not shown) formed on the surface of the VCSEL element 9 and one end of the conductor pattern 10 can be shortly wired. gradually Arrange to narrow.
[0034]
The connection point between the conductor pattern 12 and the through-hole conductor 10 constitutes a bent portion (bent portion), but the high-frequency signal that transmits the distance between the connection points, that is, the distance from the center to the center of the adjacent through-hole conductors 10. By making the wavelength shorter than ¼ (λ / 4), the characteristic impedance change of the high-frequency signal line acting on the high-frequency signal can be reduced.
[0035]
Actually, even when the characteristic impedance changes at intervals of λ / 4, the transmission characteristics of the high-frequency signal are deteriorated. Therefore, it is preferable to set the interval between the connection points to ¼ or less of λ / 4.
[0036]
For example, when transmitting a high-frequency signal having a bandwidth of 15 GHz into a dielectric having a relative dielectric constant of 9, the highest frequency of the high-frequency signal is 15 GHz and its wavelength λ _15G Is about 6.7 mm. In this case, the length of the through-hole conductor 10 and the conductor patterns 11, 12, 13 is set to λ _15G It is shorter than about 0.42 mm which is / 16, and is arranged so that each contact is smoothly connected from the conductor pattern 11 to the conductor pattern 13.
[0037]
By configuring the high-frequency signal line of the optical package P1 in this way, a VCSEL element 9 that allows a high-frequency electrical signal to enter from the rear of the back surface perpendicularly to the surface of the VCSEL element 9 and emits an optical signal in front of the surface. The mounting structure can be configured in a small size and with a wide band. For example, the optical module is mounted on the side end portion, and can be suitably used for an optical module assembly such as a thin card type inserted into the slot. In addition, since the substrate 1 is a dielectric, a large number of fine wirings can be formed, and it can be used for a complicated circuit that handles a large number of signals.
[0038]
Of the electrical wiring of the optical package P <b> 1, the DC line is constituted by a part of each of the through-hole conductor 10, the conductor patterns 11, 12, 13 and the external electrode lead 14. A part of the DC line is connected to a comb-like parallel plate conductor 12d constituting the capacitor.
[0039]
By configuring the DC line of the optical package P1 in this way, the fluctuation of the DC voltage applied to the VCSEL element 9 can be reduced with a simple structure, and the operation of the VCSEL element 9 can be stabilized. In addition, since the substrate 1 is a dielectric, a large number of fine wirings can be formed, and it can be used for a complicated circuit that handles a large number of signals.
[0040]
In part of the through-hole conductor 10 and the conductor pattern 12, a heat-dissipating through-hole conductor 10e and a heat-dissipating conductor pattern 12e are further formed for heat dissipation of the VCSEL element 9 or the VCSEL driver 23, and heat-dissipating fins 24 are provided. The heat radiating through-hole conductor 10e, the heat radiating conductor pattern 12e, and the heat radiating fins 24 are thermally connected to ensure a heat radiating path.
[0041]
By configuring the heat dissipation structure of the optical package P1 in this manner, a wide heat dissipation surface can be easily secured on a surface other than the surface 16 of the substrate 1, and the VCSEL element 9 and the VCSEL driver 23 mounted on the optical package P1 are cooled. And has the effect of operating them stably.
[0042]
Next, another configuration of the optical package P1 will be described in detail.
[0043]
As the dielectric material used for the substrate 1, ceramic materials such as alumina, aluminum nitride, and glass ceramic can be used.
[0044]
The conductor patterns 11, 12, and 13 are formed by printing a conductor film containing any one of Au, Ni, Cu, W, Mo, and the like, and they are connected by a through-hole conductor 10 made of Cu, W, or the like.
[0045]
One end of the external electrode lead 14 is accommodated in a recess called castellation provided on the mounting surface 19 of the optical module on the external electronic circuit board, and is brazed with silver, and the joint is held on three sides.
[0046]
As a result, the external electrode lead 14 is fixed to the base 1 on the three surfaces at one end of the external electrode lead 14, so that the base 1 can be firmly fixed to the mounting base 8. Further, since the mounting surface 19 of the optical module on the external electronic circuit board can be brought into close contact with the mounting substrate 8 without any gap or with a small gap, mounting with stable transmission characteristics of the high frequency signal can be performed.
[0047]
In the present embodiment, the external electrode lead 14 is used as a connection terminal to the mounting substrate 8, but instead of the external electrode lead 14, a terminal electrode group composed of a plurality of grid-like terminal electrodes is provided in at least three regions. You may form in.
[0050]
Further, by providing means for securing an optical path vertically above the surface 16, an edge-emitting optical semiconductor device such as a Fabry-Perot laser diode (FP-LD) or a distributed feedback laser diode (DFB-LD), a waveguide type It can also be used for an end face light-receiving optical semiconductor element such as a photodiode (WG-PD), and the same effect as described above can be obtained.
[0051]
When mounting the VCSEL and the VCSEL driver and its peripheral circuit electronic elements, a part of them may be mounted in another cavity formed on the back surface 17 in addition to mounting them all in the cavity 15.
[0052]
Also, when mounting the transimpedance and its peripheral circuit electronic elements as a PIN-PD or APD and preamplifier as in the mounting of the VCSEL, a part of them is formed on the back surface 17 except that all are mounted in the cavity 15. It may be mounted in another cavity.
[0053]
Further, the mounting of FP-LD, DFB-LD, or WG-PD is the same as described above.
[0054]
By mounting in this way, a large mounting area can be obtained with the same optical package size, a large number of elements can be mounted, and an optical semiconductor element and a peripheral circuit for driving it can be integrated. Thereby, it is possible to realize a small-sized and highly functional optical module that can perform complicated processing. Further, since the optical semiconductor element and the peripheral circuit for driving the optical semiconductor element are close to each other, there is little deterioration of the electric signal in the electric wiring connecting between them.
[0055]
Next, the configuration of the optical module M1 using the optical package P1 and assembling the VCSEL element 9 as a module will be described in detail.
[0056]
The optical module M1 mounts the VCSEL element 9 on the optical package P1 together with the VCSEL driver 23 and the like, performs electrical wiring, optically aligns the VCSEL element 9 and the optical waveguide, and supports the optical waveguide. To complete the optical package P1.
[0057]
Specifically, first, the VCSEL element 9 is mounted together with the VCSEL driver 23 and the like in the cavity 15 of the base body 1 which is a mounting base, and an electrode (not shown) of the VCSEL element 9 or the VCSEL driver 23 and one end of the conductor pattern 11 are mounted. Are electrically connected by a gold ribbon 20.
[0058]
Next, the transparent window fitting 3 is disposed on the metal fitting 2 of the base 1 so as to cover the VCSEL element 9. A transparent sapphire window (not shown) is disposed in the upper opening of the transparent window fitting 3. A first metal protector 4 having a cylindrical shape and having a flange portion 4a formed on one end side is disposed on the transparent window fitting 3 so that the flange portion 4a is on the base 1 side. A lens (not shown) is accommodated in the first metal protector 4 and is bonded and fixed with a transparent adhesive. Further, in the same manner as the first metal protector 4, a cylindrical ferrule 21 in which an optical fiber 22 that is optically connected to the LD is housed is accommodated in a cylindrical second metal protector 5. Two metal protectors 5 are accommodated in the first metal protector 4. As described above, the first and second metal protectors 4 and 5 are provided with the flange portions 4a and 5a so that an optical connector receptacle (not shown) can be fitted.
[0059]
If necessary, an optical isolator for removing reflected return light propagating through the optical fiber 22 is disposed inside the metal protector 4.
[0060]
The metal fitting 2 is made of Kovar or the like and is brazed to the base 1. Further, a transparent metal ring 3 made of Kovar, stainless steel, and the like and provided with a sapphire window is mounted on the VCSEL element 9 and then seam welded to the metal fitting 2 so that the VCSEL element 9 is air-tight. It is tightly sealed. Thereby, the VCSEL element 9 can be protected for a long lifetime.
[0061]
The first metal protector 4 and the second metal protector 5 are made of Kovar or stainless steel.
[0062]
Finally, mounting of the optical module M1 on the external electronic circuit board will be described.
[0063]
The optical module M1 is mounted on the side end 8a of the mounting substrate 8 which is an external electronic circuit board. At the same time, the IC 6 for driving the optical module M1 and the electronic elements 7 such as capacitors and resistors constituting the peripheral circuit are also mounted on the mounting base 8 to complete the optical module assembly A1.
[0064]
By adopting a structure in which the external electrode lead 14 is attached to the mounting surface 19 of the optical module on the external electronic circuit board, solder such as cream solder is applied to the surface of the mounting substrate 8 in advance on the mounting electrode of the mounting substrate. M1, IC6 and electronic element 7 can be collectively mounted through a solder reflow process of about 260 ° C.
[0065]
As described above, according to this embodiment, the optical module can be automatically assembled together with the components constituting the peripheral circuit on the external electronic circuit board by solder reflow or the like, and the mountability is excellent.
[0066]
Thus, according to the optical package P1 and the optical module M1 using the optical package P1, it is suitable for mounting, for example, a VCSEL or other surface-emitting optical semiconductor element, and is excellent in mass production, small in size, excellent in high frequency characteristics, and highly reliable. An optical package and an optical module using the same can be provided.
[0067]
【Example】
Hereinafter, an embodiment of the optical package P1 that further embodies the present invention will be described.
[0068]
The substrate 1 was formed by laminating six layers of sheet-like alumina ceramic having a thickness of 3.9 mm □, a thickness of 0.25 mm, and a relative dielectric constant of 9.4. Conductive patterns 11, 12, and 13 were formed on each layer, and the layers of the conductive patterns 11, 12, and 13 of each layer were connected by through-hole conductors 10 having a diameter of 0.1 mm to form electrical wiring. At this time, the conductor pattern 13 and the through-hole conductor 10 were arranged in a stepped manner, and the conductor pattern 11 and the conductor pattern 13 were smoothly connected.
[0069]
Further, the cavity 15 was formed by forming a hole in one layer of the surface 16 on the surface 16 of the substrate 1. Also, a recess 18 on the back surface of the base body is formed on the back surface 17 of the base body 1 in the same manner, and the mounting surface 19 of the optical module on the external electronic circuit board 19 (side surface of the recess 18 on the back surface of the base body) is 0.3 mm wide and deep. A castellation having a thickness of 0.2 mm was formed.
[0070]
Further, an external electrode lead 14 having a width of 0.2 mm, a thickness of 0.15 mm, and a length of 1.98 mm was fixed to the castellation with silver solder. A gap of 0.05 mm between the castellation and the external electrode lead 14 was filled with silver brazing in the length direction of the external electrode lead 14 over 0.48 mm so that the three surfaces of the external electrode lead 14 were in contact with the silver brazing.
[0071]
Finally, a metal fitting 2 made of a FeNiCo alloy having a width of 0.4 mm and a thickness of 0.5 mm was silver brazed to the surface 16 of the base 1 to complete the optical package P1.
[0072]
The optical package P1 is mounted on the side end portion 8a of the mounting substrate 8 on which a coplanar line having a characteristic impedance of 50Ω is formed, and the coplanar line on the mounting substrate 8 and the external electrode lead 14 are electrically connected to each other. As a result of measuring frequency response characteristics by inputting / outputting electric signals between one end of the coplanar lines on 8 and one end of the conductor pattern 11, the characteristics shown in FIG. 10 were obtained. From this result, it was confirmed that the reflection characteristics are greatly improved by arranging the conductor pattern 13 and the through-hole conductor 10 in a stepped manner and smoothly connecting the conductor pattern 11 and the conductor pattern 13.
[0073]
【The invention's effect】
According to the optical package and the optical module using the same according to the present invention, the following remarkable effects can be obtained.
[0074]
According to the optical package of the first aspect, the optical module can be configured in a small size and a wide band. For example, the optical module can be suitably used for a photoelectric conversion module assembly of a thin card type or the like in which an optical module is mounted at an end and inserted into a slot. Is possible. In addition, a large number of fine wirings can be formed and used for a complicated circuit that handles a large number of signals.
[0075]
According to the optical package of the second aspect, the electrical wiring of the optical package can be further broadened.
[0077]
Claim 3 According to this optical package, the substrate can be firmly fixed to the external electronic circuit board. Further, since the mounting surface of the optical module can be closely attached to the external electronic circuit board without a gap or with a small gap, mounting with stable transmission characteristics of high-frequency signals can be performed.
[0078]
Claim 4 According to this optical package, the fluctuation of the DC voltage applied to the optical semiconductor element or the electronic element can be reduced with a simple structure, and the operation of the optical semiconductor element or the electronic element mounted on the optical package can be stabilized.
[0079]
Claim 5 According to this optical package, there is little deterioration of the signal for operating the optical semiconductor element. Further, the module including the electronic circuit for operating the optical semiconductor element can be reduced in size.
[0080]
Claim 6 According to this optical package, it is possible to easily secure a wide heat radiating surface on the surface other than the surface of the substrate, cool the optical semiconductor element or electronic element mounted on the optical package, and operate them stably.
[0081]
Claim 7 According to the optical package, since the radiation fin is connected to the conductor pattern for mounting the electronic element or the optical semiconductor element, the cooling effect can be further enhanced.
[0082]
Claim 8 According to the optical module, it is excellent in mountability to an external electronic circuit board, and exerts excellent effects in downsizing, wide band, high reliability, and mass productivity improvement.
[Brief description of the drawings]
FIG. 1 is a front perspective view schematically illustrating an embodiment of an optical package according to the present invention.
FIG. 2 is a rear perspective view schematically illustrating an embodiment of an optical package according to the present invention.
FIG. 3 is a perspective view from another angle on the back side, schematically illustrating an embodiment of an optical package according to the present invention.
FIG. 4 is a perspective view showing an internal state for schematically explaining an embodiment of an optical package according to the present invention.
FIG. 5 is a diagram schematically illustrating an embodiment of an optical package according to the present invention, and is a perspective view showing a state when a surface emitting laser (VCSEL) is mounted on the optical package.
FIG. 6 is a diagram schematically illustrating an embodiment of an optical package according to the present invention, and is a cross-sectional view showing a state when a surface emitting laser (VCSEL) is mounted on the optical package.
FIG. 7 is a diagram schematically illustrating another embodiment of the optical package according to the present invention, in which a heat-dissipating conductor pattern is formed inside the optical package and is thermally applied to the heat-dissipating fins attached to the outside. It is sectional drawing which shows a structure when it is made to connect to.
FIG. 8 is a perspective view schematically illustrating an embodiment of an optical module according to the present invention.
FIG. 9 is a side view schematically illustrating a state when the optical module according to the present invention is mounted on an external electronic circuit board.
FIG. 10 is a graph illustrating frequency response characteristics of electrical wiring of an optical package according to the present invention.
FIG. 11 is a cross-sectional view schematically illustrating an example of a conventional optical package and an optical module using the same.
FIG. 12 is a graph for explaining the frequency response characteristic of the electrical wiring of the optical package according to the prior art, and a graph showing the reflection characteristic (S11).
FIG. 13 is a diagram for explaining the frequency response characteristics of the electrical wiring of the optical package according to the prior art, and is a graph showing transmission characteristics (S21).
[Explanation of symbols]
1: Substrate
2: Metal fitting (constructs support)
3: Transparent window fittings (constructs support)
4: 1st metal protective body (it comprises a support body)
5: Second metal protector (constructs a support)
6: IC
7: Electronic device
8: Mounting substrate (external electronic circuit board)
8a: Side end (external electronic circuit board)
9: VCSEL element (surface emitting laser element; optical semiconductor element)
10: Through-hole conductor (consisting of ground conductors 10a and 10b and signal conductor 10c)
10e: Heat dissipation through-hole conductor
11: Conductor pattern (consisting of ground conductors 11a and 11b and signal conductor 11c formed on the substrate surface)
12: Conductor pattern (consisting of ground conductors 12a and 12b and signal conductor 12c formed on the inner layer of the substrate)
12d: Comb-like parallel plate conductor (constitutes a capacitor)
12e: Conductive pattern for heat dissipation
13: Conductor pattern (consisting of ground conductors 13a and 13b and signal conductor 13c formed on the back surface of the substrate)
14: External electrode lead (lead conductor)
15: Cavity
16: surface of substrate
17: Back side of substrate
18: Concave part on the back of the substrate
19: Mounting surface of optical module on external electronic circuit board (18 side surfaces)
20: Au wire
21: Ferrule (constructs an optical waveguide)
22: Optical fiber (comprising an optical waveguide)
23: VCSEL driver (electronic element)
24: Radiation fin
30: Stem (composed of TO-CAN package)
31: Cap (constitutes TO-CAN package)
31a: Transparent window
32: Lead pin
33: Glass feedthrough
40: VCSEL element (surface emitting laser element)
41: Gold wire
P1: Optical package
M1: Optical module
A1: Optical module assembly

Claims (8)

A base for mounting an optical semiconductor element on a surface, having a laminated structure composed of a plurality of dielectric layers, and having a mounting surface for mounting on a side end portion of an external circuit board. A provided substrate;
A conductor pattern formed on the front surface and the back surface of the laminated structure, wherein an electric signal is input / output from the front surface side conductor pattern to the optical semiconductor element, and
It is formed inside the laminated structure, and is composed of a conductor pattern and a through-hole conductor. A stepped conductor that gradually narrows as it approaches the conductor pattern on the surface side and is shorter than ¼ of the wavelength of the electrical signal ;
A lead conductor for connecting to external wiring on an external circuit board on the mounting surface, one end of which is accommodated in the castellation and connected to the conductor pattern on the back side, and the stepped shape An optical package comprising: a lead conductor electrically connected to the conductor pattern on the surface side through a conductor. 2. The optical package according to claim 1, wherein an interval between the centers of the through-hole conductors formed in the dielectric layers adjacent to each other is set to 1/16 or less of a wavelength of the electric signal.   The optical package according to claim 1, wherein the lead conductor is held on at least three surfaces in the castellation.   4. The optical package according to claim 1, wherein a capacitor is formed in a part of the multilayer structure.   5. The optical package according to claim 1, wherein an electronic element for driving the optical semiconductor element is mounted on a front surface or a back surface of the laminated structure.   The optical package according to claim 1, wherein a radiation fin is attached to a surface excluding the surface of the laminated structure.   The heat dissipation conductor pattern is provided as a part of the conductor pattern for mounting the electronic element or the optical semiconductor element, and the heat dissipation fin is connected to the heat dissipation conductor pattern. Light package.   An optical module comprising at least an optical semiconductor element mounted on the optical package according to claim 1.

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