JP2005039300A - Optical semiconductor module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical semiconductor module having an excellent capability. <P>SOLUTION: The optical semiconductor module is provided with a substrate and an array semiconductor laser element mounted on the substrate and made of a plurality of modulator-attached semiconductor laser elements arrayed such that their major surfaces and end surfaces are respectively made flush, each of the modulator-attached semiconductor laser elements having a modulator section provided with a surface electrode on the surface, and a laser section having surface electrodes on the surface with an optical axis arranged in alignment with the optical axis of the modulator section, and the plurality of modulator-attached semiconductor laser elements made of the modulator-attached semiconductor laser elements having different distances between respective emission end surfaces of laser beams and the modulator sections, wherein on the substrate, a plurality of linear strip lines with the ends connected with the surface electrodes of the modulator sections of respective modulator-attached semiconductor laser elements, extending in the direction perpendicular to the respective optical axes of the modulator-attached semiconductor laser elements, and feed lines connected to the respective surface electrodes of the respective laser section of the modulator-attached semiconductor laser elements are provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical semiconductor module, and more particularly to an optical semiconductor module including a semiconductor laser element with an ultrahigh-speed modulator used for large-capacity optical fiber communication.

  FIG. 5 is a diagram for explaining the structure of an optical semiconductor module provided with a conventional semiconductor laser device with a modulator. FIG. 5 (a) is a perspective view showing the structure of the semiconductor laser device with a modulator. b) is a perspective view showing the structure of the substrate on which the semiconductor laser element with modulator is placed, and FIG. 5C is the structure of the optical semiconductor module in which the semiconductor laser element with modulator is placed on the substrate. It is a perspective view shown. In the figure, 1001 is a semiconductor laser element with a modulator, 1002a and 1002b are surface electrodes provided on the surface of the modulator part 1020 of the semiconductor laser element with modulator 1001, and 1003a and 1003b are electrically connected to the back side of the modulator part 1020. The back surface electrode 1004 is a surface electrode of the laser portion 1040 of the modulator-equipped semiconductor laser element 1001, and 1005 is a back surface electrode electrically connected to the back surface side of the laser portion 1040. The substrate 1012 is formed by disposing a microstrip line substrate 1006, which is a plate-like member made of a material such as alumina, with low loss of high frequency on a chip carrier 1011 made of CuW or the like. The chip carrier 1011 functions to reinforce the microstrip line substrate 1006 and serves as a ground conductor for the microstrip line. 1007a, 1007b, 1007d, and 1007e are strip lines made of gold plating or the like disposed on the microstrip line substrate 1006, 1007c is a feed line made of gold plating or the like disposed on the microstrip line substrate 1006, and 1007f is made of gold plating or the like. 1008 is a 50Ω termination resistor provided on the strip line 1007b, and 1009b, 1009d, 1009e, and 1009f are metallized inner surfaces of the microstrip line substrate 1006, such as gold plating, and a chip carrier. This is a through hole for conducting to 1011.

  This optical semiconductor module is configured by placing a semiconductor laser element 1001 with a modulator on a microstrip line substrate 1006 so that the surface thereof faces the surface of the microstrip line substrate 1006, and a surface electrode. 1002a and strip line 1007a, surface electrode 1002b and strip line 1007b, back electrode 1003a and strip line 1007d, back electrode 1003b and strip line 1007e, surface electrode 1004 and feed line 1007c, back electrode 1005 and ground line 1007f Are bonded to each other.

  FIG. 6 is a view for explaining a method of assembling the optical semiconductor module. In the figure, the same reference numerals as those in FIG. 5 denote the same or corresponding parts. In this conventional optical semiconductor module, a semiconductor laser element 1001 with a modulator and a substrate 12 are prepared, and AuSn solder bumps 1010 are respectively formed on the respective electrodes on the surface of the laser element 1001. The semiconductor laser element 1001 is placed on a microstrip line substrate 1006 that has been heated to about 340 ° C. so that the surfaces thereof face each other, and the surface electrodes 1002a and 1002b on the modulator side of the laser element 1001 are placed. The back surface electrodes 1003a and 1003b, the laser-side surface electrode 1004, and the back surface electrode 1005 are respectively connected to the microstrip lines 1007a, 1007b, 1007d, and 1007e, the feed line 1007c, and the ground line 1007f through AuSn solder bumps 1010. Press and heat up It is formed by deposition.

Next, a method for manufacturing a semiconductor laser device with a modulator used in a conventional optical semiconductor module and a method for manufacturing solder bumps on the laser device will be described with reference to FIG. FIG. 4 is a process diagram showing a conventional method of manufacturing a semiconductor laser chip with a modulator and a method of manufacturing a solder bump, and is a cross-sectional view perpendicular to the laser resonator length direction. In FIG. 4, 1051 is an undoped InP substrate, 1052 is an active layer in the laser part, 1052 is a waveguide layer, 1062 is a p-type InP second cladding layer, 1053 is a high-resistance InP current blocking layer, and 1054 is an n-type InP hole trap. 1055 is a p-type InGaAs contact layer, 1056 is a trench formed by etching, 1057 is a SiO ₂ insulating film, 1059 is a Cr / Au film, 1060 is a front electrode, and 1061 is a back surface. Electrode.

  First, as shown in FIG. 4A, a waveguide 1052 and a p-type InP second cladding layer 1062 are grown on an undoped InP substrate 1051 and etched to a depth reaching the substrate 1051. After processing into a ridge stripe shape having a predetermined width extending in the direction of the laser resonator length, a high resistance InP current blocking layer 1053 and an n-type InP hole trap layer 1054 are grown so as to embed the ridge stripe shape portion, Next, a p-type InP cladding layer 1055 and a p-type InGaAs contact layer 1056 are grown. Note that a diffraction grating is formed on the waveguide layer 1052 in the region where the laser portion is formed, but is omitted here. Further, an isolation region is formed between these regions in order to electrically separate the modulator portion and the laser portion, but they are omitted here.

Further, as shown in FIG. 4 (b), an undoped InP substrate 1051 is formed in a region where the ridge stripe shape portion is not formed in order to reduce the capacitance of the modulator section and to conduct to the back side of the element. An opening 1057 is formed by etching so as to reach, and an SiO ₂ insulating film 1058 is formed on the entire surface of the substrate 1051 as shown in FIG. 4C, and then directly above the waveguide 1052 and deepest of the groove 1057. Each of the openings is provided with an opening in which the contact layer 1056 and the undoped InP substrate 1051 are exposed on the bottom surface. Thereafter, as shown in FIG. 4 (d), a Cr / Au film 1059 is formed on the entire surface of the substrate 1051, and as shown in FIG. 4 (e), the region on the waveguide layer 1052 and the opening 1057 are formed by patterning. In this region, the Cr / Au film 1059 is separated, and a front surface electrode 1060 and a back surface electrode 1061 are formed to obtain a semiconductor laser device 1001 with a modulator.

  Further, as shown in FIG. 4 (f), the entire surface of the laser device 1001 is covered with a resist, a part of the window is opened using an exposure technique, and Au plating and Sn plating are sequentially performed thereon to remove the resist. To do. As a result, an AuSn solder bump 1010 having a melting point of 280 ° C., which is an alloy having an Au composition of 80% and an Sn composition of 20%, is obtained.

  In this optical semiconductor module, the chip carrier 1011 is grounded, the back surface electrodes 1003a, 1003b, and 1005 of the modulator-equipped semiconductor laser element are set to the ground potential, and a DC current is injected from the feed line 1007c into the laser unit to cause the laser in the laser unit. By generating light and applying a modulation signal to the modulator section from the microstrip line 1007d, the laser light is modulated and modulated light can be obtained from the end face.

  In the conventional optical semiconductor module, a single substrate of alumina having a small high-frequency loss angle is used as the microstrip line substrate 1006 on which the semiconductor laser device 1001 with modulator is mounted, and the modulation of the semiconductor laser device 1001 with modulator is formed thereon. The vessel portion 1020 and the laser portion 1040 are bonded together. However, since the thermal conductivity of alumina is as low as 0.3 W / cm · ° C. in this way, it is difficult to diffuse the heat generated in the vicinity of the light emitting region when current is injected into the laser unit 1040 and the heat dissipation is poor. Therefore, since the temperature rise near the light emitting region becomes large, there is a problem that it is difficult to obtain a sufficient light output with a low current consumption particularly when operating at a high temperature.

Conversely, when a material having a high thermal conductivity of 2.6 W / cm · ° C. such as SiC, which is generally used as a submount material of a laser part as a microstrip line substrate, is excellent in heat transferability but high frequency There is a problem that it is difficult to obtain excellent high frequency characteristics in a wide frequency range from DC to several tens GHz in the modulator section.
Therefore, it has been very difficult to obtain a high-performance optical semiconductor module that has excellent high-frequency characteristics and can operate even at high temperatures.

  On the other hand, FIG. 7 is a perspective view for explaining the structure of another conventional optical semiconductor module. In the figure, the same reference numerals as those in FIG. 5 denote the same or corresponding parts. The chip 2001 is formed by arranging a plurality of semiconductor laser elements 1001 with a modulator described with reference to FIG. 5 so that their optical axes are parallel to each other. However, here, a back electrode is not provided on the surface of the laser element 1001, but a common back electrode (not shown) is provided on the back surface of the element. 2002 is a semiconductor laser section, 2003 is a modulator section, and 2005 is a microstrip line substrate made of a plate-like member made of alumina or the like with a low high-frequency loss. It has been. Reference numeral 2006 denotes a semiconductor laser element with an array type modulator arranged on the microstrip line substrate 2005 so as to extend in a direction perpendicular to the optical axis of the semiconductor laser element with an array type modulator 2001. A plurality of strip lines for applying a high-frequency signal whose end portions on the side of 2001 are arranged on the same straight line in the optical axis direction. The number of strip lines 2006 constitutes the semiconductor laser element 2001 with an array type modulator. The number of semiconductor laser elements 1001 is the same as the number of semiconductor laser elements 1001 to be processed. Reference numeral 2007 denotes a feed line arranged on the same straight line at equal intervals in a direction perpendicular to the optical axis of the semiconductor laser element with an array type modulator 2001. The arrangement interval is the semiconductor laser element 2001 with an array type modulator. The interval is equal to the interval between the laser elements 1001 constituting the. Reference numeral 2010 denotes a semiconductor with an array type modulator arranged so as to extend in a direction perpendicular to the optical axis of the semiconductor laser element with an array type modulator 2001 arranged on the microstrip line substrate 2005. A plurality of strip lines in which end portions on the laser element 2001 side are arranged on the same straight line in the optical axis direction, and the plurality of strip lines 2010 and the plurality of strip lines 2006 are each of the semiconductor laser element 2001 with an array type modulator. Located on both sides. Reference numeral 2008 denotes a termination resistor inserted into each of the plurality of strip lines 2010, and 2009 denotes a through hole in which metallization such as gold plating is made, and each of the ground conductor on the back surface of the microstrip line substrate 2005 and each of the plurality of strip lines 2010. And connected.

  In this optical semiconductor module, an array type modulator-equipped semiconductor laser element 2001 is placed and bonded on a microstrip line substrate 2005 so that the back surface thereof faces the surface of the microstrip line substrate 2005. . Each strip line 2006 and the surface electrode 1002a on the modulator section 2003 side of each semiconductor laser element 1001 constituting the semiconductor laser element 2001 with an array type modulator are bonded to each strip by a bonding wire 2004 such as a gold wire. The line 2010 is connected to each surface electrode 1002b on the modulator section 2003 side of each semiconductor laser element 1001. The back electrode of the semiconductor laser element with an array type modulator 2001 is bonded and grounded to a grounding metal film or the like provided on the microstrip line substrate 2005 at a position where the element 2001 is placed.

  In this optical semiconductor module, the chip carrier 1011 is grounded, the back electrode (not shown) of the semiconductor laser element with an array type modulator 2001 is set to the ground potential, and the semiconductor laser element with an array type modulator 2001 is connected to each feeder line 1007c. A laser current is generated in each laser unit 2002 by injecting a DC current into each laser unit 2002 to generate laser light in the laser unit 2002 and applying a modulation signal to each modulator unit 2003 from each microstrip line 1007d. Modulated light can be obtained from the end face by modulating the light.

  However, in the optical semiconductor module formed by placing the semiconductor laser element 2001 with an array type modulator on the microstrip line substrate 2005, the semiconductor laser element 2001 with an array type modulator is formed in parallel. As the number of laser elements 1001 arranged increases, the surface electrodes 1002a and 1002b of the modulator section 2003 of each semiconductor laser element with modulator 1001 and the strips arranged on both sides of the semiconductor laser element with array type modulator 2001 Since the length of the bonding wire 2004 connecting the lines 2006 and 2010 becomes long, the waveform of the modulated light output from each laser element is disturbed not only by self-inductance but also by crosstalk due to mutual inductance between the wires. It becomes. Therefore, there is a problem that a high-performance optical semiconductor module excellent in high frequency characteristics cannot be obtained.

  Further, in order to avoid the occurrence of a problem due to the length of the bonding wire 2004, the strip lines 2006 and 2010 are exposed on the end face side where the laser beam of the semiconductor laser element 2001 with an array type modulator is emitted, that is, the modulation. Although it is conceivable to arrange it near the container 1020 side, in this case, there arises a problem that a bonding wire necessary for connection prevents light emission.

  In addition, it is conceivable to arrange the strip lines 2006 and 2010 near the end face on the laser unit 2002 side of the array type semiconductor laser element 2001. Usually, however, an output light intensity monitor and output light control are provided near the end face on the laser unit 2002 side. Such a strip line or a bonding wire cannot be provided for mounting a photodiode for use.

As described above, there has conventionally been a problem that an optical semiconductor module with good performance cannot be obtained.
The present invention has been made to solve such problems, and an object thereof is to obtain an optical semiconductor module having excellent performance.

  An optical semiconductor module according to the present invention comprises a substrate, a modulator portion mounted on the substrate and having a surface electrode on the surface thereof, and an optical axis thereof being collinear with an optical axis of the modulator portion. A plurality of semiconductor laser elements with modulators having different distances between the laser light emission end face and the modulator part, the surface and the end face of the laser part having a laser part provided with a surface electrode on the surface thereof And an array type semiconductor laser element arranged side by side so as to constitute the same plane, and an end portion thereof is connected to each of the surface electrodes of the modulator section of each of the semiconductor laser elements with a modulator on the substrate. A plurality of linear strip lines extending in a direction perpendicular to the optical axis of the modulator-equipped semiconductor laser element, and a feed line connected to each of the surface electrodes of the laser portion of each of the modulator-equipped semiconductor laser elements. Like having One in which the.

  In the optical semiconductor module, a ground conductor is provided on the back surface of the substrate, and the strip line is a microstrip line.

  In the optical semiconductor module, a plurality of grounding lines connected to the ground conductor on the back surface through through holes are provided on the surface of the substrate in correspondence with the plurality of strip lines. On the surface of the modulator part of each modulator-equipped semiconductor laser element that constitutes the type semiconductor laser element, there are provided back-side electrodes that are electrically connected to the back side, and the back-side electrodes and the grounding lines are connected to each other. It is made to adhere.

  As described above, according to the present invention, the substrate, the modulator unit mounted on the substrate and having the surface electrode on the surface thereof, and the optical axis thereof are collinear with the optical axis of the modulator unit. A plurality of semiconductor laser elements with modulators having different distances between the laser light emission end face and the modulator part. Arrayed semiconductor laser elements arranged side by side so as to form the same plane, and on the substrate, the end portion is connected to each of the surface electrodes of the modulator section of each of the semiconductor laser elements with a modulator. A plurality of linear strip lines extending in a direction perpendicular to the optical axis of the modulator-equipped semiconductor laser element; and a feed line connected to each of the surface electrodes of the laser section of each of the modulator-equipped semiconductor laser elements; To have Et al., The surface electrode of the modulator portion of the semiconductor laser elements constituting the semiconductor laser device with an array modulators can be connected stripline 210a~210e directly, there is no need to use a bonding wire or the like to connect. For this reason, the length of the bonding wire becomes longer as the number of laser elements constituting the array increases, so that the characteristics of the laser element with an array type modulator are not deteriorated, and the array is formed without impairing the high frequency characteristics. There is an effect that the number of elements can be increased and a high-performance optical semiconductor module having excellent high-frequency characteristics can be obtained.

  In addition, according to the present invention, since the ground conductor is provided on the back surface of the substrate, and the strip line is a microstrip line, a high-performance optical semiconductor module having excellent high-frequency characteristics can be obtained. is there.

  Further, according to the present invention, a plurality of grounding lines connected to the ground conductor on the back surface through through holes are provided on the front surface of the substrate corresponding to the plurality of strip lines. On the surface of the modulator part of each modulator-equipped semiconductor laser element that constitutes the type semiconductor laser element, there are provided back-side electrodes that are electrically connected to the back side, and the back-side electrodes and the grounding lines are connected to each other. Since they are bonded, there is an effect that a high-performance optical semiconductor module having excellent high frequency characteristics can be obtained.

Embodiment 1 FIG.
In the optical semiconductor module according to the present invention, the material for the region on which the modulator part is placed and the region on which the laser part is placed on the substrate on which the semiconductor laser element with a modulator is placed are different. The material of the region where the modulator unit is placed has a smaller high-frequency loss angle than the material of the region where the laser unit is placed, and the material of the region where the laser unit is placed is placed on the modulator unit. The material having a higher thermal conductivity than the material of the region to be placed.

  FIG. 1 is a diagram for explaining the structure of an optical semiconductor module according to Embodiment 1 of the present invention, and FIG. 1 (a) shows the structure of a semiconductor laser device with a modulator that is a part of the optical semiconductor module. FIG. 1B is a perspective view showing the structure of a substrate on which a modulator-equipped semiconductor laser device is placed, and FIG. 1C is a diagram in which the modulator-equipped semiconductor laser device is placed on a substrate. It is a perspective view which shows the structure of an optical semiconductor module.

  In the figure, a modulator-equipped semiconductor laser device 1 includes a modulator section 20 having surface electrodes 2a and 2b on its surface and a surface electrode 4 on its surface, the optical axis of which is the optical axis of the modulator section 20. And a laser unit 40 arranged on the same straight line. The optical waveguide 30 of the laser element 1 extends along the optical axis, and the end face 20 a from which light on the modulator unit 20 side is emitted is disposed perpendicular to the direction in which the optical waveguide 30 extends. The back surface electrodes 3a and 3b are disposed on both sides of the optical axis, and each is electrically connected to the back surface side of the modulator unit 20. Although only one of the back surface electrodes 3a and 3b may be provided, it is preferable in terms of operating characteristics that they are provided on both sides of the optical axis. The back electrode 5 is electrically connected to the back side of the laser unit 40.

The substrate 70 is formed on a chip carrier 11 made of CuW or the like, on a first plate member 71 that functions as a microstrip line substrate made of alumina (Al ₂ O ₃ ), AlN, or the like whose material has a small high-frequency loss angle; A second plate member 72 that functions as a submount made of a material such as SiC having a high thermal conductivity is provided side by side with the first plate member 71. The first plate-like member 71 may be made of any other material as long as the loss angle of the high frequency with respect to the second plate-like member 72 is small. As the material, other materials may be used as long as the materials have higher thermal conductivity than the first plate member 72. The chip carrier 11 has a function of fixing the two plate-like members 71 and 72 and reinforcing them and a function of serving as a ground conductor for the two plate-like members 71 and 72. Further, the thicknesses of the two plate-like members 71 and 72 are adjusted so that the step which becomes an obstacle at the time of mounting the semiconductor element 1 with a modulator does not occur, and the heights of these surfaces are the same. . Here, the plate-like members 71 and 72 are arranged so as to be spatially separated, but may be arranged to be bonded to each other. In this case, a common ground conductor made of plating or the like may be formed on the back surfaces of the plate-like members 71 and 72 without providing the chip carrier 11. Strip lines 7 a, 7 b, 7 d, and 7 e made of gold plating or the like disposed on the first plate member 71, and a chip carrier 11 serving as a ground conductor provided on the back surface side of the first plate member 71 Constitutes a microstrip line. 8 is a 50Ω termination resistor inserted on the strip line 7b, 7c is a feeding line made of gold plating or the like disposed on the second plate member 72, 7f is a grounding line made of gold plating or the like, a through hole 9b, The inner surfaces of 9d, 9e, and 9f are metallized by gold plating or the like, and serve as ground conductors with the strip lines 7b, 7d, and 7e on the surfaces of the first and second plate-like members 71 and 72, and the grounding line 7f. The chip carrier 11 is electrically connected.

  As shown in FIG. 1 (c), this optical semiconductor module has a first semiconductor laser device 1 with a modulator that has a first surface facing the surfaces of the first and second plate-like members 71, 72. The semiconductor laser device 1 with a modulator has the optical axis direction of the first plate-like member 71 and the second plate-like shape. It is the same as the arrangement direction with the member 72, and the modulator unit 20 of the semiconductor laser element 1 with modulator is on the first plate member 71 and the laser unit 40 is on the second plate member 72. It is placed so that it is located. The surface electrode 2a and the strip line 7a, the surface electrode 2b and the strip line 7b, the back surface electrode 3a and the strip line 7d, the back surface electrode 3b and the strip line 7e, the front surface electrode 4 and the feed line 7c, and the back surface electrode 5 The grounding line 7f is bonded to each other.

  Since the modulator-equipped semiconductor laser device 1 is thus placed on the substrate 70, the strip line 7a and the surface electrode 2a of the modulator section are connected, and the surface electrode 2b of the modulator section is connected to the strip line 7b. It is connected to the chip carrier 11 through the through hole 9b. The back surface electrode 3a of the modulator section is connected to the chip carrier 11 through a strip line 7d and a through hole 9d. The back surface electrode 3b of the modulator section is connected to the chip carrier 11 through a strip line 7e and a through hole 9e. Since the termination resistor 8 is inserted in the middle of the strip line 7b, the termination resistor 8 is connected in parallel with the modulator section.

  FIG. 8 is a view for explaining an assembling method of the optical semiconductor module. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. In the optical semiconductor module according to the first embodiment, a modulator-equipped semiconductor laser element 1 and a substrate 70 are prepared, and AuSn solder bumps 10 are respectively formed at predetermined positions on the surface of the laser element 1. The modulator-equipped semiconductor laser device 1 is placed on a substrate 70 that has been heated to about 340 ° C. in advance so that the surface thereof faces the surface of the substrate 70. The front surface electrodes 2a, 2b, the back surface electrodes 3a, 3b, the laser surface side surface electrode 4, and the back surface electrode 5 are respectively AuSn soldered to the strip lines 7a, 7b, 7d, 7e, the feed line 7c, and the ground line 7f. It is formed by pressure bonding via the bumps 10 and bonding by raising the temperature.

  Next, the operation will be described. The chip carrier 11 is grounded, the back electrodes 3a, 3b, 5 of the modulator-equipped semiconductor laser device 1 are set to the ground potential, and a DC current is injected from the feed line 7c into the laser unit 40 to generate laser light in the laser unit 40. Then, by applying a modulation signal from the strip line 7d to the modulator section 20, the laser light is modulated, and the modulated light is obtained from the end face 20a on the modulator side of the modulator-equipped semiconductor laser device 1.

  In this optical semiconductor module, the portion of the substrate 70 on which the modulator portion 20 of the semiconductor laser device 1 with a modulator is placed is a first plate member 71 made of alumina or the like having a small high-frequency loss angle, and the laser portion. Since the portion on which 40 is placed is the second plate-like member 72 made of SiC or the like having high thermal conductivity, in the modulator section 20, the first plate-like member 72 having a small loss angle reduces high-frequency loss. It is possible to improve the high frequency characteristics by reducing the size, and in the laser unit 30, the heat generated by the current injection can be efficiently dissipated by the second plate member. As a result, according to the optical semiconductor module according to the first embodiment, it is possible to provide a high-performance optical semiconductor module having excellent high-frequency characteristics, excellent heat dissipation, and capable of high-temperature operation.

  In the first embodiment, when the optical semiconductor module is assembled, the front electrode 4 and the back electrode 5 of the laser unit 40 of the modulator-equipped semiconductor laser, the feed line 7c and the grounding line 7f of the substrate 70, In the present invention, as shown in FIG. 2, the portion to be bonded to the surface electrode 4 and the back surface electrode 1005 of the laser portion 40 of the modulator-equipped semiconductor laser device 1 is used. Instead of providing solder bumps, thinly patterned AuSn solders 81c and 81f are respectively formed, whereby the front electrode 4 and the back electrode 5 of the laser unit 40, the feed line 7c of the substrate 70 and the grounding are formed. The work line 7f may be bonded, and even in such a case, the same effects as those of the first embodiment can be obtained.

  In the first embodiment, the case where each strip line is a microstrip line has been described. However, in the present invention, ground lines are provided on both sides of each strip line so that each strip line can be used as a coplanar line. Even in such a case, the same effects as those of the first embodiment can be obtained.

Embodiment 2. FIG.
FIG. 3 is a perspective view for explaining the structure of the optical semiconductor module according to the second embodiment of the present invention. FIG. 3 (a) shows a second plate serving as a submount on the back surface of the semiconductor laser element with a modulator. FIG. 3B is a perspective view showing the structure of a first plate member serving as a coplanar line substrate placed on the modulator-equipped semiconductor laser device, and FIG. (c) is a perspective view showing a structure of an optical semiconductor module.

  In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and the semiconductor laser element 1a with a modulator is the back surface of the laser unit 40 in the semiconductor laser element 1 with a modulator shown in FIG. The electrode is prevented from being taken out from the surface of the laser element 1, and a back surface electrode (not shown) is provided on the back surface. On the surface of the first plate-like member 91 functioning as a coplanar line substrate made of a material such as alumina having a small high-frequency loss angle, the strip line 17a extends on the same straight line and is arranged at a predetermined interval from each other. , 17b and grounding lines 19a, 19b arranged in parallel on both sides thereof. The strip lines 17a and 17b and the ground lines 19a and 19b form a coplanar line. A 50Ω termination resistor 18 is inserted into the strip line 17b, and the opposite end of the strip line 17b opposite to the strip line 17a is connected to the grounding lines 19a and 19b. Reference numeral 92 denotes a second plate member serving as a submount on which the modulator-equipped semiconductor laser device 1 is placed, and is made of a material having high thermal conductivity such as SiC. Reference numeral 93 denotes a bonding wire that connects the surface electrode 4 of the laser unit and a power supply outside the optical semiconductor module. The upper surface, the bottom surface, and at least one side surface of the second plate-shaped member 92 are metallized by gold plating or the like.

  In this optical semiconductor module, as shown in FIG. 3C, the modulator-equipped semiconductor laser chip 1a is placed on the second plate-like member 92, and its back surface is in contact with the surface of the second plate-like member 92. The first plate-like member 91 is mounted on the modulator section 20 of the modulator-equipped semiconductor laser device 1a so that the surface thereof faces the surface of the modulator-equipped semiconductor laser device 1a. Is placed in the area. The end of the strip line 17a facing the strip line 17b is bonded to the surface electrode 2a of the modulator unit 20 using AuSn solder, and the end of the strip line 17b facing the strip line 17a is connected to the surface electrode 2b of the modulator unit 20. The AuSn solder is used for bonding, and the ground electrodes 3a and 3b of the modulator unit 20 are bonded to the grounding line 19b using AuSn solder. Since the end of the strip line 17 b is connected to the surface electrode 2 b and to the ground electrode 3 bga ground line 19 b of the modulator unit 20, the termination resistor 18 is connected in parallel to the modulator unit 20.

  When the back surface of the second plate-like member 92 of this optical semiconductor module is grounded, the back electrode of the laser unit 40 is grounded. Then, a DC current is injected into the surface electrode 4 of the laser unit 40 via the bonding wire 93, the grounding lines 19a and 19b are grounded, and a modulation signal is applied from the strip line 7a, whereby the modulator of the laser element 1a The modulated light can be obtained from the end portion 20a on the portion 20 side.

  In this optical semiconductor module, the entire back surface of the modulator-equipped semiconductor laser chip 1a can be brought into contact with the second plate-shaped member 92 having a high thermal conductivity. An operable optical semiconductor module can be obtained. In addition, since the first plate-like member 91 serving as the substrate of the strip lines 17a and 17b serving as the coplanar lines for transmitting the high-frequency signal is made of a material having a small high-frequency loss angle, the high-frequency characteristics are excellent. An optical semiconductor module can be obtained.

Embodiment 3 FIG.
FIG. 9 is a perspective view for explaining the structure of the optical semiconductor module according to Embodiment 3 of the present invention. FIG. 9A shows the structure of the semiconductor laser element with an array type modulator used in the optical semiconductor module. FIG. 9B is a perspective view showing the structure of the substrate on which the semiconductor laser element with an array type modulator is placed, and FIG. 3C is a perspective view showing the structure of the optical semiconductor module.

  In the figure, the same reference numerals as those in FIG. 1 indicate the same or corresponding parts, and the array type modulator-equipped semiconductor laser device 100 has a plurality of modulations having the same structure as the modulator-equipped semiconductor laser device 1 shown in FIG. The equipped semiconductor laser elements 101a to 101e are provided side by side so that their optical axes are parallel to each other. The end surfaces from which the light of each of the semiconductor laser elements 101a to 101e is emitted and the upper surface thereof constitute the same plane. Although the case where the number of semiconductor laser elements with modulators constituting the semiconductor laser element with modulator 100 is five has been described here, the number may be any number as long as it is two or more. The semiconductor laser elements 101a to 101e with modulators constituting the semiconductor laser element with an array type modulator are provided between the modulator sections 102a to 102e and the laser sections 104a to 104e, and to the end face and the modulated light. Waveguides 103a to 103e with a small optical loss are provided between the units 102a to 102e, respectively, as necessary. The waveguides 103a to 103e are arranged in the same vertical direction to the optical axis of the semiconductor laser device 100 with an array modulator. The positions of the modulator units 102a to 102e in the optical axis direction are adjusted so that three or more modulator units 102a to 102e are not arranged on the line. Here, in particular, the distance between the modulator section 102c of the element 101c, which is the center of the five semiconductor laser elements 101a to 101e with modulator, and the end face from which the modulated light is emitted is the shortest, and the modulators of the outermost elements 101a and 101e. The distance between the portions 102a and 102e and the end face from which the modulated light is emitted is the longest.

  The substrate 200 is made of alumina or the like, and extends on both surfaces of the substrate 200 in parallel to each other from both ends of the substrate 200 toward the center of the substrate 200, and each end is arranged at a constant interval in the extending direction. The five strip line groups 204a to 204e are disposed. This interval is set to be substantially the same as the interval between adjacent elements of the laser elements 101a to 101e constituting the semiconductor laser element 100 with an array type modulator. A chip carrier 205 serving as a ground conductor is provided on the back surface of the substrate 200, whereby the five strip line groups 204a to 204e are each a microstrip line group. Note that metallization may be provided on the back surface of the substrate 200 instead of providing the chip carrier. Each of the strip line groups 204a to 204e is for applying a high-frequency signal in which end portions extending in parallel to each other from both ends of the substrate 200 toward the center direction of the substrate are arranged at a constant interval in the extending direction. The strip lines 210a to 210e, the strip lines 211a to 211e arranged at a predetermined interval with respect to these end portions, and the end portions of the strip lines 210a to 210e and the strip lines 211a to 211e facing each other, It consists of strip lines 212a to 212e and strip lines 213a to 213e provided in the vicinity thereof. A through hole 214 whose inner surface is metallized is provided in a region where the strip lines 211a to 211e, the strip lines 212a to 212e, and the strip lines 213a to 213e are provided, and a chip carrier 205 disposed on the back surface thereof. And is conducted. The strip line groups 210a to 210e are located in the vicinity of a straight line extending in a direction perpendicular to the direction in which the strip lines 210a to 210e extend through the end on the center side of the substrate 200 of each of the strip lines 210a to 210e. Are provided on the same straight line in a direction parallel to the extending direction of the strip lines 210a to 210e. In addition, grounding lines 203a to 203e are provided in the vicinity of the feed lines 202a to 202e.

  The array-type modulator-equipped semiconductor laser device 100 has the substrate 200 facing the surface of the array 100 so that the optical axis thereof is perpendicular to the extending direction of the strip line groups 204a to 204e. 200. Further, the surface electrodes 2a and 2b of the modulator sections 102a to 102e of the semiconductor laser elements 101a to 101e with modulators and the surface electrode 4 of the laser sections 104a to 104e are respectively connected to the strip line groups 204a to 204e. Only the end portions of the strip lines 210a to 210e, the end portions of the strip lines 211a to 211e opposed thereto, and the feed lines 202a to 202e paired with the end portions of the strip lines 210a to 210e are bonded via solder or the like. ing. Further, the backside electrodes 3a and 3b and the backside electrode 5 of the modulator-equipped semiconductor laser elements 101a to 101e are respectively connected to the striplines 212a to 212e and striplines 213a to 213e of the stripline groups 204a to 204e, respectively. And it adhere | attaches only via the solder | pewter etc. to the earthing | grounding lines 203a-203e which make a pair with these. At this time, since the positions of the modulator units 102a to 102e of the laser elements 101a to 101e in the optical axis direction are not constant, the strip lines 210a to 210e extending in the direction perpendicular to the optical axis are modulated with their ends connected. The modulator units 102a to 102e other than the unit units 102a to 102e are not connected.

  In this optical semiconductor module, the strip lines 210a to 210e are connected to the surface electrodes 2a of the modulator portions 102a to 102e of the semiconductor laser elements 101a to 101e, and the surface electrodes 2b of the modulator portions 102a to 102e are strips. The chip carrier 205 is connected via the lines 211 a to 211 e and the through hole 214. The back surface electrodes 3a of the modulator sections 102a to 102e are connected to the chip carrier 205 through the strip lines 212a to 212e and the through holes 214. The back surface electrodes 3 b of the modulator units 102 a to 102 e are connected to the chip carrier 205 via the strip lines 213 a to 213 e and the through holes 214. Since the termination resistor 28 is inserted in the middle of the strip lines 211a to 211e, the termination resistor 28 is connected in parallel with the modulator units 102a to 102e.

  The chip carrier 205 is grounded, the back surface electrodes 3a, 3b, 5 of the semiconductor laser element 100 with an array type modulator are set to the ground potential, and a DC current is injected from the feed lines 202a to 202e to the laser units 104a to 104e. Laser light is generated in the laser parts 104a to 104e, and a modulation signal is applied to the modulator parts 102a to 102e from the microstrip lines 210a to 210e, whereby the laser light is modulated and modulated light is obtained from the end face.

  In the present third embodiment, the surface electrodes 2a of the modulator portions 102a to 102e of the semiconductor laser elements 101a to 101e constituting the semiconductor laser element 100 with an array type modulator are strip lines 210a to 210e which are microstrip lines. Connected directly. For this reason, it is not necessary to use a bonding wire or the like for connection. Therefore, the length of the bonding wire becomes longer as the number of laser elements constituting the array increases in the conventional optical semiconductor module using the semiconductor laser element with an array type modulator. The problem that the waveform of the modulated light output from each laser element is disturbed by crosstalk due to the mutual inductance between the wires is eliminated. As a result, the number of elements constituting the array can be increased without impairing the high frequency characteristics, and there is an effect that a high performance optical semiconductor module having excellent high frequency characteristics can be obtained.

  FIG. 10 is a diagram showing a modification of the optical semiconductor module according to the third embodiment. In the figure, the same reference numerals as those in FIG. 9 denote the same or corresponding parts, and 200a denotes a loss angle of high frequency such as alumina. The first plate member 200b is made of a small material, and 200b is a second plate member made of a material having high thermal conductivity such as SiC.

  In the third embodiment, a single substrate 200 made of alumina or the like is used. However, in this modification, as shown in FIG. 10, a substrate on which an array type semiconductor laser device with a modulator is mounted. That is, the first plate-like member 200a and the second plate-like member 200b are used. That is, as described in the first embodiment, the material is different between the region where the modulator units 102a to 102e are placed and the region where the laser units 104a to 104e are placed, and the modulators The material of the region on which the laser parts 104a to 104e are placed is assumed to have a smaller high-frequency loss angle than the material of the region on which the laser parts 104a to 104e are placed. Has a higher thermal conductivity than the material of the region where the modulator portion is placed. Even in such a modification, the same effects as those of the third embodiment can be obtained, and the heat radiation from the laser units 104a to 104e can be improved, so that an optical semiconductor module capable of high-temperature operation can be obtained.

  In the third embodiment, the case where each strip line is a microstrip line has been described. However, in the present invention, ground lines are provided on both sides of each strip line so that each strip line can be a coplanar line. Even in such a case, the same effects as those of the third embodiment can be obtained.

  The optical semiconductor module according to the present invention can increase the number of elements constituting the array without impairing the high-frequency characteristics, and is a high-performance module having excellent high-frequency characteristics. As useful.

It is a perspective view which shows the structure of the optical semiconductor module which concerns on Embodiment 1 of this invention. It is a perspective view for demonstrating the assembly method of the modification of the optical semiconductor module which concerns on Embodiment 1 of this invention. It is a perspective view which shows the structure of the optical semiconductor module which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the manufacturing method of the semiconductor laser element with a modulator used for the conventional optical semiconductor module. It is a perspective view which shows the structure of the conventional optical semiconductor module. It is a perspective view which shows the assembly method of the conventional optical semiconductor module. It is a perspective view which shows the structure of the other conventional optical semiconductor module. It is a perspective view for demonstrating the assembly method of the optical semiconductor module which concerns on Embodiment 1 of this invention. It is a perspective view which shows the structure of the optical semiconductor module which concerns on Embodiment 3 of this invention. It is a perspective view for demonstrating the structure of the optical semiconductor module which concerns on Embodiment 3 of this invention. It is a perspective view which shows the structure of the optical semiconductor module which concerns on the modification of Embodiment 3 of this invention.

Explanation of symbols

1, 1a, 101a to 101e, 1001 Modulator semiconductor laser elements 2a, 2b, 1002a, 1002b Surface electrodes 3a, 3b, 1003a, 1003b Back electrode 4, 1004, 1060 Surface electrode 5, 1005, 1061 Back electrode 7a , 7b, 7d, 7e, 17a, 17b, 210a to 210e, 211a to 211e, 212a to 212e, 213a to 213e, 1007a, 1007b, 1007d, 1007e, 2006, 2010 Strip lines 204a to 204e, 1007c, 2007 Feed line 7f , 203a to 203e, 1007f Grounding line 9b, 9d, 9e, 9f, 214 Through hole 10, 1010 Solder bump 11, 1011 Chip carrier 19a, 19b Grounding line 18 Termination resistor 20, 103a to 103e , 2003 Modulator unit 20a End surface 30 on the modulator unit side Optical waveguides 40, 104a to 104e, 2002 Laser units 70, 1012, 2005 Substrate 71, 200a First plate member 72, 200b Second plate member 91 First Plate member 92 Second plate member 93, 2004 Bonding wire 100 Semiconductor laser element 1051 with array type modulator Undoped InP substrate 1052 Waveguide layer 1053 High resistance InP current blocking layer 1054 n-type InP hole trap layer 1055 p-type InP first cladding layer 1056 p-type InGaAs contact layer 1057 groove 1058 insulating film 1059 Cr / Au film 1006, 2005 microstrip line substrate 200 substrates 204a to 204e strip line group

Claims (3)

A substrate,
A modulator unit mounted on the substrate and having a surface electrode on its surface, and a laser having a surface electrode on its surface whose optical axis is collinear with the optical axis of the modulator unit And a plurality of semiconductor laser elements with modulators having different distances between the laser light emitting end face and the modulator part, the surface and the end face of which are arranged side by side. A semiconductor laser element,
On the substrate, a plurality of edge portions extending in a direction perpendicular to the optical axis of the modulator-equipped semiconductor laser element are connected to the surface electrodes of the modulator sections of the modulator-equipped semiconductor laser elements. An optical semiconductor module comprising: a linear strip line; and a feed line connected to each of the surface electrodes of the laser portion of each of the semiconductor laser elements with a modulator. The optical semiconductor module according to claim 1,
A ground conductor is provided on the back surface of the substrate,
An optical semiconductor module, wherein the strip line is a microstrip line. The optical semiconductor module according to claim 2,
On the surface of the substrate, a plurality of ground lines connected to the ground conductor on the back surface through through holes are provided corresponding to the plurality of strip lines,
On the surface of the modulator portion of each modulator-equipped semiconductor laser element that constitutes the array type semiconductor laser element, there is provided a back-surface electrode that is electrically connected to the back surface.
An optical semiconductor module, wherein each of the back surface electrodes and each grounding line is bonded.

Images