JPH11186668A - Optical semiconductor module - Google Patents

Abstract

[PROBLEMS] To reduce the size and speed of an optical semiconductor module. SOLUTION: An optical semiconductor element 3, a subcarrier 4 on which the optical semiconductor element 3 is mounted, a conductive substrate 7 on which the subcarrier 4 is mounted, a semiconductor thermal cooling element 8 on which the conductive substrate 7 is mounted, and a semiconductor element A wiring board 10 on which a driving circuit element 9 for driving the driving circuit 3 is mounted is provided inside the envelope 2. Outside the envelope 2, the optical receptacle 1 is provided on one side, and the DC voltage lead 15 and the coaxial receptacle 16 are provided on the other side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an optical semiconductor module used in the optical / telecommunications field.

[0002]

2. Description of the Related Art A technique of a pigtail type optical semiconductor module shown in FIG. 6 using a pigtail type optical fiber as an optical semiconductor module for transmitting an optical signal (Journal Light Wafer Technology Vol. LT-2, No. 4, August 1984). Fig.7) is known.

[0006] In FIG. 6, a semiconductor laser 51 is mounted on a substrate 5.
The substrate 52 is mounted on a thermoelectric heat pump (THP) 54 together with the photodetector 53.
An optical fiber 55 is arranged in the direction of the light emitted from the semiconductor laser 51. The laser drive circuit 56 is disposed adjacent to the thermoelectric heat pump 54, and is electrically connected to the semiconductor laser 51 by a plurality of bonding wires 57 via pads 61 and 62. These components are surrounded and hermetically sealed by an envelope 58, and can be connected to an external circuit by leads 59.

In this configuration, when a signal and a DC voltage are supplied to the laser drive circuit 56 from the outside of the envelope 58 via the leads 59 and the bonding wires 60, the semiconductor laser 51 is connected to the semiconductor laser 51 via the bonding wires 57. The laser drive circuit 56 operates so that current can be supplied according to the signal. During that time, the semiconductor laser 51 is controlled by an external circuit (not shown) so that the thermoelectric heat pump 54 maintains a constant temperature by absorbing or radiating heat. The driven semiconductor laser 51 emits light in the direction of the optical fiber 55 according to the signal, and the light is transmitted to the outside by optical coupling with the end face of the optical fiber 55.

On the other hand, as an example of a receptacle type optical semiconductor module, there is an optical semiconductor module disclosed in Japanese Patent No. 2570879. In this example, an optical semiconductor element (laser) is mounted on a stem having leads and is sealed with a cap. The component is arranged in a cylinder provided with a receptacle and a rod lens.

In this receptacle-type optical semiconductor module, when a signal current is supplied to the optical semiconductor element via the lead from a drive circuit provided outside, light is emitted from the optical semiconductor element. This light is collected by a rod lens and optically coupled to a ferrule fitted into the receptacle.

[0007]

However, in the pigtail type optical semiconductor module, the semiconductor laser 5
Since the pads 61 on the substrate 52 on which the circuit board 1 is mounted and the pads 62 of the drive circuit 56 are connected by a plurality of bonding wires 57, the area occupied by the pads 61 and 62 needs to be large. Therefore, when the drive circuit 56 is formed into an IC, the chip area increases, the number of chips that can be taken from the wafer decreases, and it becomes difficult to reduce the cost of the IC. Met.

In addition, it is difficult to reduce the size of the module because a configuration other than disposing the leads 59 in a direction perpendicular to the drawing direction of the optical fiber 55 cannot be adopted.

In addition, since the signal is supplied by the lead 59, in an optical semiconductor module that handles a high-speed signal of Gb / s or more, a substrate with a new device is prepared for connection with an external circuit. However, there is a problem that an assembling process becomes complicated in realizing an apparatus using this module.

Furthermore, it is difficult to realize an optical semiconductor module that is small and easy to mount, because the pigtail type optical semiconductor module has the optical fiber 55 attached.

On the other hand, in the case of the above-mentioned receptacle type optical semiconductor module, since a semiconductor thermo-cooling element for stabilizing the temperature of the optical semiconductor element required for a communication system is mounted due to a stem structure with leads, an external heat sink is required. There is a problem that a contact area with the contact cannot be secured.

Further, as in the case of the pigtail type optical semiconductor module described above, since the signal is supplied by the lead terminal, in the optical semiconductor module handling a high-speed signal of Gb / s or more, a new board is required for connection with an external circuit. Therefore, there is a problem that an assembling process becomes complicated in realizing an apparatus using this module.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to reduce the size and facilitate the mounting, to have excellent temperature stability of an optical semiconductor element, and to require a special substrate. An object of the present invention is to provide a receptacle-type optical semiconductor module capable of handling a high-speed signal of Gb / s or more without performing the above operation.

[0014]

According to a first aspect of the present invention, an optical semiconductor device, a subcarrier having the optical semiconductor device mounted thereon, a conductive substrate having the subcarrier mounted thereon, A semiconductor thermo-cooling element on which a conductive substrate is mounted to control the temperature of the optical semiconductor element; a driving circuit element for driving the semiconductor element; and a signal and power supply for mounting the driving circuit element and supplying the driving circuit element. A wiring board having wiring for performing the operation, an enclosure enclosing each element and each substrate inside, and having a DC voltage terminal and a high-speed signal terminal connected to the wiring of the wiring board, and the optical semiconductor An optical receptacle for fitting an optical connector plug that optically couples with light generated from an element, wherein the optical receptacle is provided on one side of an outer surface of the envelope. Provided with, the DC voltage terminal and said high speed signal terminal on the opposite side of the provided, and with composing the DC terminals at the lead, and constitutes the high-speed signal terminals coaxial receptacle. According to a second aspect, in the first aspect, the wiring substrate is supported in the envelope by a metal block, and is formed in a substantially L-shape in which a part facing the optical receptacle is cut off. Positioning the semiconductor thermal cooling element and the conductive substrate so as to be partially covered by the wiring substrate and not to be in contact with the metal block inside the L-shape, The carrier and the drive circuit element on the wiring board are arranged close to each other.
In a third aspect based on the second aspect, a conductive post is disposed in the envelope near the semiconductor thermal cooling element, and the conductive post and a conductive substrate mounted on the semiconductor thermal cooling element. Are connected by a lead or a wire. In a fourth aspect based on the second aspect, the metal block and the conductive substrate mounted on the semiconductor thermal cooling element are connected by a lead or a wire.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a sectional view showing the structure of a receptacle type optical semiconductor module according to a first embodiment of the present invention, and FIG. 2 is a top view of a terminal portion. is there. Reference numeral 1 denotes an optical receptacle into which an optical connector plug is fitted, and includes an optical component. Reference numeral 2 denotes an envelope for hermetically sealing a main part of the module in an airtight state, and is integrated with the optical receptacle 1.

An optical semiconductor device 3 such as a semiconductor laser is mounted on the subcarrier 4. Reference numeral 5 denotes a light detecting photodiode for detecting light emitted from the optical semiconductor element 3, and is mounted on the subcarrier 6. Reference numeral 7 denotes a conductive substrate on which both subcarriers 4 and 6 are mounted. Reference numeral 8 denotes a semiconductor thermo-cooling element on which the conductive substrate 7 is mounted, and is used for controlling the temperature of the optical semiconductor element 3. Reference numeral 9 denotes a drive circuit element formed as an IC for driving the optical semiconductor element 3, which is mounted on a wiring board 10 and is electrically connected to the optical semiconductor element 3 and the photodetecting photodiode 5. . The wiring board 10 is fixed in the envelope 2 with solder or the like so as not to contact the semiconductor thermal cooling element 8.

Reference numeral 11 denotes a terminal plate for connecting a DC voltage or a high-speed signal input from the outside. The terminal plate is located outside the envelope 2 on the side opposite to the optical receptacle 1 side.
Three ceramic substrates 11A, 11B, 1 having different lengths
1C. Ceramic substrate 11A
Are located inside the envelope 2, and the ceramic substrates 11B, 1
1C is provided so as to penetrate from the inside of the envelope 2 to the outside, and is bonded in a hermetically sealed state by being brazed to a region 2a in which a part of the envelope 2 is opened. 12 is a via penetrating between the ceramic substrates 11A and 11B,
The electrode pads 13 on the ceramic substrate 11A and the electrode pads 14 on the ceramic substrate 11C are connected. Fifteen
Are leads for external connection of a DC voltage connected to the electrode pad 14.

Reference numeral 16 denotes a coaxial receptacle,
On the side opposite to the side of the optical receptacle 1 and above the terminal plate 11. Reference numeral 17 denotes a center conductor of the coaxial receptacle 16, which is held by the beads 18 and has an electrode pad 13 'on the ceramic substrate 11A.
It is connected to the.

Reference numerals 19 and 19 'denote wirings formed on the wiring board 10. One end is connected to the drive circuit element 9 by a bonding wire (not shown), and the other end is a bonding wire. They are connected to electrode pads 13, 13 'on ceramic substrate 11A via 20, 20'.

The bonding wires 20, 2
0 ′, bonding wires between the wirings 19 and 19 ′ and the electrode pads of the driving circuit element 9, and bonding wires between the driving circuit element 9 and the electrode pads of the subcarriers 4 and 6, etc. A 30 μmφ wire is used.

Here, supply of a DC voltage and supply of a high-speed signal to the optical semiconductor module will be described. First, a DC voltage is supplied from an external wiring board (not shown) to the lead 15, and from this lead 15, the electrode pad 14 on the ceramic substrate 11C, the via 12 penetrating the ceramic substrates 11A and 11B, and the ceramic substrate 11A. Through the upper electrode pad 13, the bonding wire 20, and the wiring 19 on the wiring board 10, the wiring reaches the electrode pad of the drive circuit element 9. As a result, the direct current of the optical semiconductor element 3 is controlled by the internal circuit of the drive circuit element 9.

On the other hand, the high-speed signal is transmitted to the coaxial receptacle 16
Of the drive circuit element 9 via the electrode pad 13 ′ on the ceramic substrate 11 A, the bonding wire 20 ′, and the wiring 19 ′ on the wiring board 10. As a result, the current of the optical semiconductor element 3 is controlled by the internal circuit of the drive circuit element 9 in response to the high-speed signal.

Light emitted from the optical semiconductor element 3 is transmitted to the optical receptacle 1 via a lens or the like (not shown), and optically coupled to a ferrule of a connector plug (not shown) fitted into the optical receptacle 1. Is done. During this operation, the optical semiconductor element 3 is controlled and maintained at a predetermined temperature by the semiconductor thermo-cooling element 8, and maintains stable operation characteristics with little fluctuation of the oscillation wavelength.

As described above, in the optical semiconductor module of the present embodiment, since the DC voltage and the high-speed signal can be supplied from the side opposite to the optical receptacle 1 side in the envelope 2, the cross section of the optical receptacle 1 It is possible to realize a small optical semiconductor module having substantially the same size and shape as the optical semiconductor module.
In addition, since a plurality of the optical semiconductor modules can be arranged in parallel and mounted on a wiring board, a high-density optical transmitting and receiving apparatus can be realized by combining with an optical receiving module having the same configuration. Furthermore, since the optical receptacle 1 and the coaxial receptacle as a high-speed signal interface are used, not only is mounting easy, but also high-speed signals of Gb / s or more can be easily handled without using a special circuit board. be able to.

In the above description, the terminal board 11 composed of the ceramic substrates 11A, 11B and 11C is configured as another component different from the wiring board 10, but may be configured as one integrated component. Can also. Further, a DC voltage can be supplied by using a side printed wiring board instead of the via 12 of the terminal board 11.

[Second Embodiment] FIG. 3 is a perspective view of a main part of an optical semiconductor module according to a second embodiment, and FIG. 4 is a side view of the module of FIG. is there. 1 and 2 are denoted by the same reference numerals.

In FIG. 3, reference numeral 31 denotes a wiring board made of a ceramic multilayer board on which the drive circuit element 9 is mounted, and is arranged so as not to contact the subcarriers 4, 6 and the conductive substrate 7. The wiring board 31 corresponds to the wiring board 10 shown in FIGS.
Side is cut out so as to be narrower than the terminal 11 side, and is supported by a brazed L-shaped metal block 32. Between the wiring 33 on the wiring board 31 and the electrode pad of the drive circuit element 9, between the electrode pad of the drive circuit element 9 and the electrode pad of the subcarrier 4 of the optical semiconductor element 3, and between the electrode pad of the drive circuit element 9 and The photodetecting photodiodes 5 are connected to the electrode pads of the subcarriers 6 by bonding wires 34, 35, 36.

In FIG. 4, the metal block 32 supporting the wiring board 31 has a shape in which a lower portion of the wiring board 31 facing the subcarrier 4 protrudes by a distance L1.
The lower surface of the protruding portion 32a is separated upward from the upper surface of the conductive substrate 7 by a distance L2. Further, the wiring board 31
Are close to the subcarrier 4 by a distance L3.
The upper surface of the drive circuit element 9 and the upper surface of the subcarrier 4 are substantially the same.

Therefore, in the second embodiment,
In the wiring board 31, the length of the plurality of wirings 33 running side by side on the drive circuit element 9 side can be kept short, and the space between the running wirings can be widened from the middle and connected to the terminal board 11 side. Further, since a ceramic multilayer substrate is used as the wiring board 31, the DC supply wiring and the ground wiring can be arranged in the inner layer by the via, and the wiring density can be improved in the limited inner space of the envelope 2. By employing a coplanar waveguide for the signal wiring, interference between the signal and the power wiring can be reduced.

Further, since the subcarrier 4 and the wiring board 31 are brought close to each other, a bonding wire 35 for connecting between the output electrode pad of the drive circuit element 9 and the electrode pad of the subcarrier 4 of the optical semiconductor element 3 is provided. Can be shortened, so that deterioration due to ripples or the like which are likely to appear in a high-frequency signal waveform can be reduced and transmitted to the optical semiconductor element 3.
For example, when L3 = 0.2 mm, the length of the bonding wire 35 can be reduced to about 0.5 mm (inductance corresponding to about 0.5 nH), and a problem in transmitting a high-speed signal of Gb / s or more is as follows. Does not occur.

Further, since there is no contact between the conductive substrate 7 or the semiconductor thermal cooling element 8 and the wiring board 31 or the metal block 32, they are thermally separated from each other.
Can be reduced.

[Third Embodiment] FIG. 5 is a diagram showing a main part of an optical semiconductor module according to a third embodiment in which the main part of the optical semiconductor module according to the second embodiment is further improved. Here, the envelope 2 is located close to the semiconductor thermal cooling element 8.
A metal post 41 is arranged in the bottom of the substrate, and the conductive substrate 7 and the metal post 41 are electrically connected by a lead 42.

In the third embodiment, the metal post 41 and the lead are connected in parallel with a bonding wire used as a return current path from one terminal (anode) of the optical semiconductor element 3 to the ground electrode pad of the drive circuit element 9. Since the path by 42 is connected, the reactance component due to the bonding wire can be reduced. Therefore, it is possible to reduce the total inductance component substantially given by the sum of the output electrode pad of the drive circuit element 9 and the bonding wire connecting the electrode pad (cathode) of the subcarrier 4 for the optical semiconductor element 3. Therefore, it is possible to realize a mounting configuration that can follow a higher-speed signal.

The leads 42 can be replaced with wires.
Further, the metal post 41 is not specially prepared, and the wiring board 3 is not provided.
The lead 42 may be connected to the metal block 32 supporting the first metal block 1 so that the metal block 32 has the same function as the metal post 41.

[0035]

As described above, according to the first aspect of the present invention, a DC voltage and a high-speed signal can be supplied to the side of the envelope opposite to the side of the optical receptacle. Optical semiconductor module can be realized. Also,
Since a plurality of the optical semiconductor modules can be arranged in parallel and mounted on a wiring board, a high-density optical transmitting / receiving device can be realized by combining with an optical receiving module having the same configuration. Further, since the optical receptacle and the coaxial receptacle as an interface for high-speed signals are provided, it is possible to realize an optical semiconductor module which can not only be easily mounted but also easily cope with high-speed signals of Gb / s or more.

According to the second aspect of the present invention, the bonding wire connecting between the output electrode pad of the drive circuit element and the electrode pad of the optical semiconductor element subcarrier can be shortened.
Signals can be transmitted to the optical semiconductor device with less deterioration of high-speed signals such as ripples. In addition, since the optical semiconductor element and the drive circuit element are thermally separated from each other, thermal interference between them is suppressed, and a large reduction in electric power for driving the semiconductor thermal cooling element can be expected. Furthermore, by using a multilayer substrate as the wiring substrate, the wiring density can be improved even in a limited envelope space, and by adopting a coplanar waveguide for the signal wiring, the wiring between the signal and the power supply can be improved. Interference can be reduced. Therefore, an optical semiconductor module that operates at high speed with low power consumption can be realized.

According to the third and fourth aspects of the invention, since the inductance of the portion connected to the optical semiconductor element can be reduced, it is possible to realize an optical semiconductor module that can follow a higher-speed signal.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical semiconductor module according to a first embodiment of the present invention.

FIG. 2 is a plan view of a terminal portion of the optical semiconductor module.

FIG. 3 is a perspective view of a part of an optical semiconductor module according to a second embodiment.

FIG. 4 is a side view of the optical semiconductor module of FIG.

FIG. 5 is an explanatory diagram of an optical semiconductor module according to a third embodiment.

FIG. 6 is an internal plan view of a conventional optical semiconductor module.

[Explanation of symbols]

1: optical receptacle, 2: envelope, 3: optical semiconductor element,
4: Subcarrier, 5: Photodetector photodiode, 6:
Subcarrier, 7: conductive substrate, 8: semiconductor thermal cooling element, 9: drive circuit element, 10: wiring substrate, 11: terminal plate, 11A, 11B, 11C: ceramic substrate, 12:
Via, 13, 13 ', 14: electrode pad, 15: lead, 16: coaxial receptacle, 17: center conductor, 18:
Beads, 19, 19 ': Wiring, 20, 20': Bonding wire, 31: Wiring board made of ceramic multilayer board, 32: Metal block, 33: Wiring, 34, 35, 3
6: bonding wire, 41: metal post, 42: lead, 51: semiconductor laser, 52: substrate, 53: photodetector, 54: thermoelectric heat pump, 55: optical fiber, 5
6: laser drive circuit, 57: bonding wire, 5
8: envelope, 59: lead, 60: bonding wire, 61, 62: electrode pad.

Claims (4)

[Claims] An optical semiconductor device, a subcarrier on which the optical semiconductor device is mounted, a conductive substrate on which the subcarrier is mounted, and a semiconductor heat source mounted with the conductive substrate for controlling the temperature of the optical semiconductor device. A cooling element, a driving circuit element for driving the semiconductor element, a wiring board on which the driving circuit element is mounted and a wiring for supplying a signal and power to the driving circuit element, and the respective elements and the respective substrates And an optical connector plug for optically coupling with light generated from the optical semiconductor element, and an envelope having a DC voltage terminal and a high-speed signal terminal connected to the wiring of the wiring board. An optical semiconductor module comprising: an optical receptacle, wherein the optical receptacle is provided on one side of an outer surface of the envelope, and the DC voltage terminal and An optical semiconductor module comprising: a high-speed signal terminal; a direct-current terminal formed by a lead; and a high-speed signal terminal formed by a coaxial receptacle. 2. The wiring board is supported in the envelope by a metal block, and a part of a side facing the optical receptacle is cut into a substantially L-shape, inside the L-shape and the L-shape. The semiconductor thermal cooling element and the conductive substrate are positioned so as to be partially covered by the wiring substrate and not to be in contact with the metal block, and the subcarrier and the wiring substrate on which the optical semiconductor element is mounted are disposed. 2. The optical semiconductor module according to claim 1, wherein the driving circuit element is brought close to the driving circuit element. 3. A conductive post is disposed in the envelope in the vicinity of the semiconductor thermal cooling element, and a lead or wire is provided between the conductive post and a conductive substrate mounted on the semiconductor thermal cooling element. The optical semiconductor module according to claim 2, wherein the optical semiconductor module is connected by: 4. The optical semiconductor module according to claim 2, wherein the metal block and the conductive substrate mounted on the semiconductor thermal cooling element are connected by a lead or a wire.