JP4076062B2 - Array type semiconductor laser device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an array type semiconductor laser device and a semiconductor laser module on which the array type semiconductor laser device is mounted, and more particularly to a technique effective when applied to prevention of crosstalk in an array type semiconductor laser device.
[0002]
[Prior art]
Semiconductor lasers can produce coherent light with the same frequency and phase by orderly inducing stimulated radiation in which the excited electrons and holes radiate and recombine in the active layer formed on the semiconductor substrate. It has high straightness and coherence and is used in a wide range of fields such as information processing and optical communication.
[0003]
With the progress of informatization, the traffic of information communication networks continues to increase rapidly. To cope with this increase in traffic, the optical communication network, which is the backbone of the information communication network, has to process more information. High speed is required. Therefore, for high-speed and large-capacity optical transmission of 10 Gbps or more, wavelength division multiplexing (WDM) technology that multiplexes a plurality of optical signals having different wavelengths and transmits them to one optical fiber is common. It is coming.
[0004]
In wavelength division multiplex communication, a plurality of optical signals are multiplexed by a multiplexer. The plurality of optical signals to be combined are signal systems called independent channels, and the number of channels in the transmission apparatus is the same. The semiconductor laser element is required. When an individual semiconductor laser element is mounted for each channel, the optical system must be adjusted for each element, which is cumbersome. Therefore, an array type semiconductor laser device in which a plurality of semiconductor laser elements are integrated is provided. It is used. In this semiconductor laser device, as shown in FIG. 1, an n-type semiconductor substrate 1 using InP or the like, an n-type cladding layer 2 using InAlAs or the like, an active layer 3 using InGaAlAs or the like, InAlAs / InP, or the like. The p-type cladding layer 4 used and the insulating film 5 in which silicon oxide and silicon nitride are laminated are sequentially laminated, and this layer structure is separated by a groove 6 formed in the separation region to form a 4-channel structure. A semiconductor laser element is provided.
[0005]
Each semiconductor laser element has a ridge structure in which grooves are formed in the clad layer 4 on both sides of the light emission center region, and the insulating film 5 is removed from the ridge portion and InGaAs or the like is used on the clad layer 4. A p-type cap layer 7 is formed, and an anode electrode 8 for applying a voltage to the active layer by laminating Ti, Pt, etc. mainly composed of gold on the cap layer 7 and the insulating film 5 is formed. Similarly, a cathode electrode 9 that is electrically connected to the semiconductor substrate 1 is formed.
[0006]
[Problems to be solved by the invention]
However, in such an array-type semiconductor laser device, since a plurality of semiconductor laser elements are formed on the same semiconductor substrate, electrical, thermal, and optical crosstalk occurs during the operation of the semiconductor laser and are adjacent to each other. The semiconductor laser element may be adversely affected. That is, electrical or electromagnetic leakage occurs during high-frequency operation such as 10 Gbps, and induces a part of the signal in the adjacent semiconductor laser element. This becomes noise and causes deterioration of characteristics.
[0007]
An object of the present invention is to solve these problems and provide a technique for preventing crosstalk between semiconductor laser elements in an array type semiconductor laser device.
The above and other problems and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.
[0008]
[Means for Solving the Problems]
Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
In a semiconductor laser device in which a plurality of semiconductor laser elements are arranged on a single semiconductor substrate, a shield portion is formed in an isolation region between the semiconductor laser elements. In the semiconductor laser module, the semiconductor laser device and an optical fiber optically coupled to the semiconductor laser device are attached to a substrate and housed in a case.
[0009]
According to the present invention described above, by providing a shield portion in the isolation region of the semiconductor laser device in which a plurality of semiconductor laser elements are arranged in parallel, crosstalk between adjacent semiconductor laser elements can be prevented during operation of the semiconductor laser. Thus, deterioration of the characteristics of the semiconductor laser device can be prevented. In addition, the module can be easily mounted on a substrate by using an array type semiconductor laser device, and crosstalk between adjacent semiconductor laser elements does not occur, so that the reliability of the module can be improved.
[0010]
Embodiments of the present invention will be described below.
Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
2 is a perspective view showing a semiconductor laser device according to one embodiment of the present invention, FIG. 3 is a partially enlarged longitudinal sectional view taken along line aa in FIG. 2, and FIG. 4 is b in FIG. -It is a partial expanded longitudinal cross-sectional view along line -b.
[0012]
In the semiconductor laser device of the present embodiment, an n-type semiconductor substrate 1 using InP or the like, an n-type cladding layer 2 using InAlAs or the like, an active layer 3 using InGaAlAs or the like, p using InAlAs / InP or the like. The layer structure is formed by sequentially laminating a mold cladding layer 4 and an insulating film 5 in which silicon oxide and silicon nitride are laminated, and this layer structure is electrically separated by a groove 6 formed in a separation region. Four-channel semiconductor laser elements are arranged in parallel on a single semiconductor substrate.
[0013]
Each semiconductor laser element has a ridge structure in which grooves are formed in the clad layer 4 on both sides of the light emission center region, and the insulating film 5 is removed from the ridge portion and InGaAs or the like is used on the clad layer 4. A p-type cap layer 7 is formed, and an anode electrode 8 for applying a voltage to the active layer by laminating Ti, Pt, etc. mainly composed of gold on the cap layer 7 and the insulating film 5 is formed. Similarly, a cathode electrode 9 that is electrically connected to the semiconductor substrate 1 is formed.
[0014]
In the semiconductor laser device of the present embodiment, the shield portion 10 is provided in the separation region where the groove 6 is formed. The shield part is composed of an electrode 10a formed in the groove 6 and an electrode 10b provided on the opposite surface facing the electrode 10 and a plurality of via holes 10c provided at predetermined intervals to conduct the opposing electrodes 10a and 10b. ing.
[0015]
By connecting the shield portion 10 to, for example, a ground potential and fixing the potential, crosstalk between adjacent semiconductor laser elements can be prevented during operation of the semiconductor laser. For this reason, even during high-frequency operation such as 10 Gbps, electrical or electromagnetic leakage is prevented, and noise is not generated in the adjacent semiconductor laser element, thereby preventing deterioration of the characteristics of the semiconductor laser device. be able to.
[0016]
FIG. 5 is a plan view showing a state in which the semiconductor laser device is attached to the substrate for mounting on the module, and FIG. 6 is a longitudinal sectional view taken along the line aa in FIG. The substrate 11 and the semiconductor laser device 12 using silicon or the like are formed on the semiconductor laser device 12, for example, by face-down mounting in which the anode electrode 8 of the semiconductor laser device 12 is bonded and connected to the ground wiring 11a of the substrate 11. The detected marker and the marker formed on the substrate 11 are detected and adjusted and attached to a predetermined position.
[0017]
In the present embodiment, the alignment of the semiconductor laser device 12 and the substrate 11 can be done only once by using the array type semiconductor laser device 12, but it is attached when attaching individual semiconductor laser elements having the number of channels. The semiconductor laser elements must be individually aligned.
[0018]
Similarly, a monitor photodiode 13 is attached to the substrate 11. In the drawing, individual photodiodes are attached to the photodiodes 13 for each channel. However, the photodiodes can be arrayed.
[0019]
The semiconductor laser device 12 and the photodiode 13 were formed on the cathode electrode 9 and the substrate 11 after melting and soldering a solder material such as gold-tin alloy deposited on the substrate 11 by reflow, and connecting and fixing to the substrate 11. A predetermined wiring is connected by a bonding wire or the like. Similarly, the electrode of the photodiode 13 and a predetermined wiring are connected by a bonding wire or the like. If necessary, the shield electrode 16 connected to the shield part 10 of the semiconductor laser device 12 is also connected to the ground potential by a bonding wire or the like.
[0020]
Next, an optical fiber 15 is attached to the V-shaped groove 14 formed on the substrate, and optical coupling adjustment is performed so that the emission center of each semiconductor laser element and the optical axis of the optical fiber 15 coincide with each other. The optical fiber 15 is fixed to the substrate 11 by curing the adhesive using a curing means such as ultraviolet irradiation or heating.
[0021]
In the optical module, the substrate 11 to which the semiconductor laser device 12 and the optical fiber 15 are connected is fixed to a case or the like and is covered together with a driving IC or the like.
[0022]
In the module of the present embodiment, by using an array type semiconductor laser device, it is easy to mount the semiconductor laser device on the substrate, and crosstalk between adjacent semiconductor laser elements does not occur. And the reliability of the module can be improved.
[0023]
Although the present invention has been specifically described based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the scope of the invention. It is.
[0024]
【The invention's effect】
The effects obtained by the representative ones of the inventions disclosed in this application will be briefly described as follows.
(1) According to the present invention, by providing a shield portion in the isolation region of a semiconductor laser device in which a plurality of semiconductor laser elements are arranged in parallel, crosstalk between adjacent semiconductor laser elements is prevented during operation of the semiconductor laser. There is an effect that can be.
(2) According to the present invention, the above effect (1) has an effect that electrical or electromagnetic leakage can be prevented even during high-frequency operation.
(3) According to the present invention, the effect (2) has an effect that no noise is generated in the adjacent semiconductor laser element.
(4) According to the present invention, due to the effect (3), there is an effect that the characteristic deterioration of the semiconductor laser device can be prevented.
(5) According to the present invention, there is an effect that the reliability of the module can be improved by the effect (4).
[Brief description of the drawings]
FIG. 1 is a perspective view showing a conventional array type semiconductor laser device.
FIG. 2 is a perspective view showing an array type semiconductor laser device according to an embodiment of the present invention.
3 is a partially enlarged longitudinal sectional view taken along the line aa in FIG. 2. FIG.
4 is a partially enlarged longitudinal sectional view taken along line bb in FIG. 2. FIG.
FIG. 5 is a plan view showing a substrate on which a semiconductor laser device according to an embodiment of the present invention is mounted;
6 is a longitudinal sectional view taken along line aa in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Semiconductor substrate, 2 ... Cladding layer, 3 ... Active layer, 4 ... Cladding layer, 5 ... Insulating film, 6 ... Groove, 7 ... Cap layer, 8 ... Anode electrode, 9 ... Cathode electrode, 10 ... Shield part, 10a , 10b ... electrode, 10c ... via hole, 11 ... substrate, 12 ... semiconductor laser device, 13 ... photodiode, 14 ... groove, 15 ... optical fiber, 16 ... shield electrode.

Claims (2)

In an array type semiconductor laser device in which a plurality of semiconductor laser elements are arranged in parallel on a single semiconductor substrate,
Forming a shield part in a separation region between the semiconductor laser elements ;
2. The array type semiconductor laser device according to claim 1, wherein the shield part is composed of electrodes formed on both sides of the semiconductor substrate so as to face each other, and a plurality of via holes provided at predetermined intervals to conduct the electrodes .   2. The array type semiconductor laser device according to claim 1, wherein the shield portion is connected to a ground potential.

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