阅读说明：本技术 光学半导体装置 (Optical semiconductor device ) 是由 宫田充宜 于 2019-12-17 设计创作，主要内容包括：一种光学半导体装置,其设置有：壳体,其具有侧壁；馈通件,其穿透所述壳体的侧壁并具有伸出部,所述伸出部从所述侧壁朝向所述壳体的外部伸出；连接端子,其电连接到安装在所述壳体中的部件,并设置在所述馈通件的所述伸出部上；第一温度感测部,其设置在所述壳体的侧壁的外壁上,以感测所述壳体的温度；以及柔性基板,其一个端部连接到所述连接端子,并且其从所述一个端部离开的一部分连接到所述第一温度感测部。所述第一温度感测部设置在所述外壁和所述柔性基板之间。(An optical semiconductor device provided with: a housing having a sidewall; a feedthrough penetrating a sidewall of the case and having a protruding portion protruding from the sidewall toward an outside of the case; a connection terminal electrically connected to a component mounted in the housing and provided on the protruding portion of the feedthrough; a first temperature sensing part disposed on an outer wall of a side wall of the case to sense a temperature of the case; and a flexible substrate, one end portion of which is connected to the connection terminal, and a portion thereof which is separated from the one end portion is connected to the first temperature sensing part. The first temperature sensing portion is disposed between the outer wall and the flexible substrate.)

1. An optical semiconductor device, comprising:

a base having a sidewall;

a feedthrough penetrating the sidewall of the base and having a protrusion protruding from the sidewall toward an exterior of the base;

a connection terminal electrically connected to a component mounted in the base and provided on the protruding portion of the feedthrough;

a first temperature detection part that is provided on an outer wall of the side wall of the base and detects a temperature of the base; and

a flexible substrate, one end of which is connected to the connection terminal, and a place of the flexible substrate departing from the one end is connected to the first temperature detection part,

wherein the first temperature detection portion is provided between the outer wall and the flexible substrate.

2. The optical semiconductor device according to claim 1,

the first temperature detection portion is bonded to an outer wall via a heat-dissipating resin.

3. The optical semiconductor device according to claim 1 or 2,

the thickness of the first temperature detection portion is equal to the amount of protrusion of the protrusion portion.

4. The optical semiconductor device according to any one of claims 1 to 3, further comprising:

a wavelength-tunable laser element housed inside the base; and

a second temperature detection unit that detects a temperature of the wavelength tunable laser element,

wherein the connection terminal inputs an electrical signal into the wavelength tunable laser element via the wavelength tunable laser element, the second temperature detection portion, and a first wiring on the flexible substrate.

5. The optical semiconductor device according to any one of claims 1 to 4,

a second wiring provided on the flexible substrate and having a pad connected to the electrode of the first temperature detection portion on the same surface is provided on a surface different from the surface on which the first wiring is provided.

Technical Field

The present invention relates to an optical semiconductor device. This patent application is based on and claims the priority benefits of prior japanese patent application No.2018-243706, filed on 26.12.2018, the entire contents of which are incorporated herein by reference.

Background

An optical semiconductor device has been developed in which a semiconductor laser element or the like is accommodated in a base thereof and which has a terminal for inputting or outputting an electric signal on the base (for example, see patent document 1). There is a case where a flexible substrate is used for connection with an external component (for example, see patent document 2).

Documents of the prior art

Patent document

Patent document 1: japanese patent application laid-open No.2001-244545

Patent document 2: japanese patent application laid-open No.2007-123741

Disclosure of Invention

An optical semiconductor device of the present invention includes: a base having a sidewall; a feedthrough penetrating a sidewall of the base and having a protruding portion protruding from the sidewall toward an outside of the base; a connection terminal electrically connected to a component mounted in the base and provided on the protruding portion of the feedthrough; a first temperature detection unit which is provided on an outer wall of a side wall of the base and detects a temperature of the base; and a flexible substrate having one end connected to the connection terminal and a portion thereof away from the one end connected to the first temperature detection portion, wherein the first temperature detection portion is provided between the side wall and the flexible substrate.

Drawings

Fig. 1A illustrates a plan view of an optical semiconductor device according to a first embodiment;

fig. 1B illustrates a cross-sectional view of the optical semiconductor device;

FIG. 2 illustrates a front view of an optical semiconductor device;

FIG. 3A illustrates a front view of a flexible substrate;

FIG. 3B illustrates a front view of the flexible substrate;

fig. 4A illustrates a front view of a case where a flexible substrate is connected to a lead pin;

fig. 4B illustrates a front view of a case where the flexible substrate is connected to the lead pins;

FIG. 5 illustrates a cross-sectional view of a wavelength tunable laser element;

fig. 6A illustrates a cross-sectional view of an optical semiconductor device according to a second embodiment;

fig. 6B illustrates a front view of the optical semiconductor device;

fig. 7A illustrates a front view of a case where a flexible substrate is connected to a lead pin;

fig. 7B illustrates a front view of a case where the flexible substrate is connected to the lead pins; and

fig. 8 illustrates a front view of a case where the flexible substrate is connected to the lead pins.

Detailed Description

Problems to be solved by the disclosure

The number of information types such as inputting of an electric signal into a semiconductor laser element, temperature detection, control of temperature between the inside of a base of the semiconductor laser element and the outside of the base is increasing. When the number of terminals is smaller than the number of information types, for example, when terminals for thermistors are not secured, it may be difficult to detect the temperature. The number of terminals may be increased according to the type of information. However, as the size of the device is reduced, it is difficult to rearrange the terminals. Accordingly, an object of the present invention is to provide an optical semiconductor device capable of detecting temperature with a reduced number of terminals.

Effects of the disclosure

According to the present disclosure, it is possible to suppress an increase in the number of terminals and detect temperature.

Modes for carrying out the invention

[ description of embodiments of the invention ]

First, details of embodiments of the present disclosure will be described as listed below.

An embodiment of the present disclosure is (1) an optical semiconductor device including: a base having a sidewall; a feedthrough penetrating the sidewall of the base and having a protrusion protruding from the sidewall toward an exterior of the base; a connection terminal electrically connected to a component mounted in the base and provided on the protruding portion of the feedthrough; a first temperature detection unit which is provided on an outer wall of a side wall of the base and detects a temperature of the base; and a flexible substrate having one end connected to the connection terminal and a portion thereof spaced apart from the one end connected to the first temperature detection portion, wherein the first temperature detection portion is disposed between the side wall and the flexible substrate. The first temperature detection portion is not connected to the external connection terminal. Therefore, the number of external connection terminals can be suppressed from increasing. Also, since the first temperature detection portion is provided on the side wall of the base, the temperature can be detected.

(2) The first temperature detection part may be bonded to the sidewall via a heat-dissipating resin. With this configuration, the temperature can be accurately detected by the first temperature detecting portion.

(3) The thickness of the first temperature detection part may be equal to an amount of protrusion of the protrusion part. When the thermistor is provided in the space around the protruding portion, the space can be effectively utilized. Also, the optical semiconductor device can be downsized.

(4) A wavelength tunable laser element housed inside the base may also be provided. A second temperature detection unit for detecting the temperature of the wavelength tunable laser element may be provided. The connection terminal may input an electrical signal into the wavelength tunable laser element via a first wiring provided on the wavelength tunable laser element, the second temperature detection portion, and the flexible substrate. The temperature in the base can be regulated by means of a temperature regulating element. Also, the number of connection terminals can be suppressed from increasing.

(5) A second wiring may be provided on a surface different from the surface on which the first wiring is provided, the second wiring being provided on the flexible substrate and having a pad connected to the electrode of the first temperature detection portion. The flexible substrate may be connected to the connection terminal and the first temperature detection part.

[ details of embodiments of the invention ]

Specific examples of an optical semiconductor element and a manufacturing method thereof, and an optical integrated semiconductor element and a manufacturing method thereof according to embodiments of the present disclosure are described below with reference to the drawings. It should be noted that the present disclosure is not limited to these examples but is shown by the claims, and all modifications are intended to be included within the scope of the claims and the equivalents thereof.

First embodiment

Fig. 1A illustrates a plan view of an optical semiconductor device 100 according to a first embodiment. Fig. 1B illustrates a cross-sectional view of the optical semiconductor device 100. The broken line of fig. 1A indicates the path of the output light of the wavelength tunable laser element 30. In fig. 1A, the thermistor 40 and the flexible substrate 70 are not illustrated. Fig. 1A and 1B are schematic diagrams. The wiring patterns and the number of lead pins 24 may vary.

As illustrated in fig. 1A and 1B, the optical semiconductor device 100 is a TOSA (transmitter optical subassembly) that includes a base 10, a feedthrough 20, a wavelength tunable laser element 30, a thermistor 40 (first temperature detection portion), and a flexible substrate 70. The base 10 is a rectangular parallelepiped shape having a longitudinal dimension of 13mm, a transverse dimension of 7mm and a height dimension of 4 mm. The side walls of the base 10 are made of, for example, an iron-nickel-cobalt alloy. The base plate of the base 10 is made of, for example, copper-tungsten alloy. One of the side walls of the base 10 has a window 18. A lens is disposed in the window 18. The light is output through the window 18 toward the outside. The other side wall of the base 10 has a feedthrough 20 for inputting and outputting an electric signal and has a thermistor 40.

Feedthrough 20 is made of, for example, alumina (Al)₂O₃) Etc. and extends from the inside of the base 10 to the outside of the base 10. Below the feed-through, the thermistor 40 is attached to the side wall 10a of the base 10 by an adhesive. The adhesive is, for example, a resin-based heat-dissipating adhesive (e.g., an epoxy-based resin or a silicone-based resin) having high thermal conductivity. The thermal conductivity of the heat-dissipating adhesive is, for example, 10W/mK. Therefore, the pedestal 10 can be accurately detectedThe temperature of (2). The surface of the feedthrough 20 and the surface of the thermistor 40 lie in the same plane.

The submount 10 houses the temperature adjustment element 12, the carrier 14, the chip carrier 16, the wavelength tunable laser element 30, the lens 32, the beam splitters 34 and 36, and the light receiving elements 37 and 38. These components are sealed in the base 10.

The temperature adjustment element 12 includes a peltier element and functions as a TEC (thermoelectric cooler). The carrier 14 and chip carrier are made of, for example, Al₂O₃And the like. The carrier 14 is mounted on the temperature adjustment element 12. The chip carrier 16, the lens 32, the beam splitters 34 and 36, the light receiving elements 37 and 38, and the etalon 39 are mounted on the carrier 14. The wavelength tunable laser element 30 is mounted on the chip carrier 16.

As described later, the wavelength tunable laser element 30 is a semiconductor element and emits light. Each of the beam splitters 34 and 36 splits the input light into two beams. The light receiving elements 37 and 38 are photodiodes or the like, and output currents when receiving light.

As illustrated in fig. 1A, two wiring patterns 15 are provided on the upper surface of the carrier 14. A plurality of wiring patterns 17 are provided on the upper surface of the chip carrier 16. Two electrodes 13 are provided on the upper surface of the temperature adjustment element 12.

The feedthrough 20 is made of ceramic including alumina, and has a protruding portion 20a that protrudes to the outside of the base 10. A plurality of wiring patterns 22 are provided on the surface of the feedthrough 20 in the base 10. The protruding portion 20a positioned outside the base 10 has a plurality of lead pins 24 protruding outside the base 10. Each lead pin 24 is electrically connected to each wiring pattern 22 through wiring in the base 10. The plurality of lead pins 24 include a lead pin connected to the wavelength tunable laser element 30, a lead pin connected to the temperature adjustment element 12, and lead pins connected to the light receiving elements 37 and 38.

One of the two wiring patterns 15 of the carrier 14 is electrically connected to the light receiving element 37, and is connected to one of the wiring patterns 22 of the feedthrough 20 via the bonding wire 25. The other of the two wiring patterns 15 is electrically connected to the light receiving element 38, and is connected to the other of the wiring patterns 22 via another bonding wire 25.

The wavelength tunable laser element 30 is electrically connected to the wiring pattern 17 of the chip carrier 16 via the bonding wire 26. The wiring pattern 17 is also connected to the wiring pattern 22 via bonding wires 25. The electrodes 13 of the temperature adjustment element 12 are electrically connected to the wiring pattern 22 of the feedthrough 20 via other bonding wires 25. As described above, the wiring pattern 22 is electrically connected to the lead pins 24.

As illustrated in fig. 1B, the flexible substrate 70 faces the side wall 10a of the submount 10, and is connected to the lead pins 24 and the thermistor 40. The optical semiconductor device 100 is electrically connected to an external component such as a control device via the flexible substrate 70. The flexible substrate 70 is a printed circuit substrate made of an insulating material and bendable. The surface 70a of the flexible substrate 70 faces the optical semiconductor device 100. The surface 70b of the flexible substrate 70 is opposite to the surface 70 a.

The thermistor 40 is disposed between the flexible substrate 70 and the side wall 10a of the cradle 10. The thickness of the thermistor 40 is equal to the distance between the flexible substrate 70 and the side wall 10a of the base 10, and also equal to the amount of protrusion of the protrusion 20a of the feedthrough 20. When the thermistor 40 is located in the space below the protruding portion 20a, the space can be effectively utilized. Therefore, the optical semiconductor device 100 can be downsized. The amount of protrusion of the protrusion 20a and the thickness of the thermistor 40 are, for example, 0.5 mm. In the case where the thickness of the thermistor 40 is smaller than the protrusion amount of the protrusion portion 20a of the feed-through 20 and a gap is formed between the thermistor 40 and the side wall 10a of the chassis 10 from the viewpoint of an allowable error of the protrusion amount of the protrusion portion 20a and the thickness of the thermistor 40, when a heat dissipation separator is provided at the thermistor 40 and the side wall 10a of the chassis 10 and a heat dissipation adhesive is used, the thermistor 40 may be thermally connected to the side wall 10a of the chassis 10. When heat dissipation partitions having different thicknesses are prepared, the influence of heat release caused by allowable errors can be suppressed.

Fig. 2 illustrates a front view of the optical semiconductor device 100. In fig. 2, the vicinity of the feedthrough 20 and thermistor 40 is enlarged. As illustrated in fig. 2, the thermistor 40 has two electrodes 42 on its surface. The thermistor 40 has a longitudinal length of 0.8 mm. The thermistor 40 has a transverse length of 1.6 mm. The longitudinal and transverse lengths of the electrodes 42 are 0.6 mm. The lead pins 24 and the electrodes 42 are located on the side wall 10a side of the optical semiconductor device 100.

Fig. 3A and 3B illustrate front views of the flexible substrate 70. Fig. 3A illustrates a face 70 a. Fig. 3B illustrates a face 70B. As illustrated in fig. 3A, two pads 74 and two wirings 76 (second wirings) are provided on the surface 70 a. Each wiring 76 is connected to each pad 74. The wiring 76 extends together with the flexible substrate 70. As illustrated in fig. 3B, a plurality of wirings 78 (first wirings) are provided on the surface 70B. The plurality of via electrodes 72 extend from the face 70a to the face 70b and penetrate the flexible substrate 70. Each wiring extends from each via electrode 72. The wiring 76 and the wiring 78 are connected to one or more external components not illustrated.

Fig. 4A and 4B illustrate front views in a state where the flexible substrate 70 is connected to the lead pins 24. Fig. 4A illustrates the face 70a side. Fig. 4B illustrates the face 70B side.

As illustrated in fig. 4A, each lead pin 24 is inserted into each through-hole electrode 72 of the flexible substrate 70. Thus, the lead pin 24 is electrically connected to the wiring 78 of fig. 4B. The electrode 42 of each thermistor 40 is connected to each pad 74 by solder.

Fig. 5 illustrates a schematic cross-sectional view of the wavelength tunable laser element 30. As illustrated in fig. 5, the wavelength tunable laser element 30 has a TDA-DFB (tunable distributed amplification-DFB) region A, CSG-DBR (stepped sampling grating distributed bragg reflector) region B and an SOA (semiconductor optical amplifier) region C. The SOA regions C, TDA-DFB region a and CSG-DBR region B are arranged in order from the front side to the rear side.

The TDA-DFB region a has a structure in which a lower clad layer 51, an active layer 52, and an upper clad layer 54 are laminated on a substrate 50. On the upper clad layer 54, there are two or more sets of regions, one of which is a region where the contact layer 55 and the electrode 56 are laminated, and one of which is a region where the heater 58a is laminated on the insulating film 57.

The CSG-DBR region B has a structure in which a lower cladding layer 51, an optical waveguide layer 53, an upper cladding layer 54, an insulating film 57, and a heater 58B are stacked on a substrate 50. Each of the heaters 58b has a power supply electrode 59 and a ground electrode 60. The SOA region C has a structure in which a lower clad layer 51, a light amplification layer 64, an upper clad layer 54, a contact layer 65 and an electrode 66 are laminated on a substrate 50.

The substrate 50, the lower clad layer 51 and the upper clad layer 54 are integrally formed in the TDA-DFB region A, CSG-DBR region B and the SOA region C. The active layer 52, the optical waveguide layer 53 and the light amplifying layer 64 are formed on the same plane. The interface between the TDA-DFB region and the CSG-DBR region B corresponds to the interface between the active layer 52 and the optical waveguide layer 53.

A facet film 62 is formed on facets of the substrate 50, the lower clad layer 51, the optical waveguide layer 53, and the upper clad layer 54 on the SOA region C side. In an embodiment, the facet film 62 is an AR (anti-reflection) film. The facet film 62 serves as the front facet of the wavelength tunable laser element 30. A facet film 63 is formed on facets of the substrate 50, the lower cladding layer 51, the optical waveguide layer 53, and the upper cladding layer 54 on the CSG-DBR region B side. In an embodiment, the facet film 63 is an AR film. The facet film 63 serves as a rear facet of the wavelength tunable laser element 30.

The substrate 50 is a crystal substrate made of, for example, n-type InP. The lower clad layer 51 has n-type conductivity. The upper cladding layer 54 has p-type conductivity. The lower clad layer 51 and the upper clad layer 54 are made of InP, for example. The lower and upper clad layers 51 and 54 confine light in the active layer 52, the optical waveguide layer 53, and the light amplifying layer 64.

A plurality of diffraction gratings (ripples) 67 are formed at given intervals in the lower cladding layer 51 of the TDA-DFB region a and the CSG-DBR region B. Therefore, the TDA-DFB region A and the CSG-DBR region B have sampled gratings. The diffraction grating 67 is made of a material having a refractive index different from that of the lower clad layer 51. When the lower clad layer 51 is made of InP, the material of the diffraction grating is, for example, Ga_0.22In_0.78As_0.47P_0.53And (4) preparing.

The active layer 52 is made of a semiconductor having a gain. The active layer 52 may have a quantum well structure consisting of Ga having a thickness of 5nm_0.32In_0.68As_0.92P_0.08Well layer made of Ga having a thickness of 10nm_0.22In_0.78As_0.47P_0.53The produced barrier layers are alternately stacked. The optical waveguide layer 53 is made of, for example, a bulk semiconductor layer and can be made of Ga_0.22In_0.78As_0.47P_0.53And (4) preparing. In this embodiment, the energy gap of the optical waveguide layer 53 is larger than that of the active layer 52.

The light amplification layer 64 realizes a gain when a current is supplied from the electrode 66, and amplifies light. The light amplifying layer 64 may have a quantum well structure consisting of Ga having a thickness of 5nm_0.35In_0.65As_0.99P_0.01Well layer made of Ga having a thickness of 10nm_0.15In_0.85As_0.32P_0.68The produced barrier layers are alternately stacked. As another structure, the optical waveguide layer 64 may be made of a bulk semiconductor layer and may be made of Ga_0.44In_0.56As_0.95P_0.05And (4) preparing. The light amplifying layer 64 may be made of the same material as the active layer 52.

Contact layers 55 and 65 are made of, for example, p-type Ga_0.47In_0.53As crystals. The insulating film 57 is made of, for example, silicon nitride (SiN) or silicon oxide (SiO)₂) And the like. The heaters 58a and 58b are thin film resistors such as TiW. The facet films 62 and 63 are AR films having a reflectance of 1.0% or less, and substantially no reflection is achieved. MgF for AR film₂And a dielectric film made of TiON.

The electrodes 56 and 66, the power supply electrode 59, and the ground electrode 60 are made of a conductive material such as Au (gold). A counter surface electrode 61 is formed on the lower surface of the substrate 50. The counter surface electrode 61 extends through the TDA-DFB region A, CSG-DBR region B and the SOA region C.

As illustrated in fig. 1A, each of the electrodes 56 and 66 and the heaters 58a and 58b is electrically connected to the wiring pattern 17 of each chip carrier 16 via each bonding wire 26.

As illustrated in fig. 1B, 4A, and 4B, the lead pins 24 are connected to the flexible substrate 70. Accordingly, an electrical signal may be input or output via the flexible substrate 70. Power is supplied to the electrodes 56 and 66 and the heaters 58a and 58b of the wavelength tunable laser element 30 via the wiring 78 of the flexible substrate 70, the lead pins 24, the wiring patterns 22 and 17, and the bonding wires 25 and 26. Thus, the wavelength tunable laser element 30 is activated. And, laser light is emitted.

As indicated by the dashed line in fig. 1A, the emitted light passes through the lens 32 and is split into two beams by the beam splitter 34. One of the split lights is output from the window 18 toward the outside. The other of the split lights is further split into two lights by the beam splitter 36. Each of the two split lights is inputted into each of the light receiving elements 37 and 38.

When the light receiving elements 37 and 38 receive the light that has passed through the etalon 39, the light receiving elements 37 and 38 output electric currents. The currents output from the light receiving elements 37 and 38 via the wiring patterns 15, the bonding wires 25, the wiring patterns 22, and the lead pins 24 are detected. The wavelength of the wavelength tunable laser element 30 may be controlled based on the current.

When power is supplied to the temperature adjustment element 12 via the wiring 78, the lead pins 24, the wiring pattern 22, and the electrodes 13 of the flexible substrate 70, the temperature in the submount 10 is adjusted and the wavelength is controlled.

The temperature may be detected using the thermistor 40. The thermistor 40 detects the temperature of the surface of the base 10 and outputs a current according to the temperature. When the current output by the thermistor 40 is detected via the electrode 42, the pad 74, and the wiring 76, the surface temperature of the submount 10 is detected. The temperature inside the base 10 can be approximately calculated from the surface temperature of the base 10.

In the first embodiment, the thermistor 40 is disposed on the side wall 10a of the base 10, and is electrically connected to the flexible substrate 70. Therefore, the temperature can be detected using an external component. And the temperature can be controlled by using external components. As illustrated in fig. 4A, the thermistor 40 is connected to the flexible substrate 70 with the electrode 42 and the pad 74. The lead pins 24 are not used. That is, the lead pin 24 is not connected to the thermistor 40. Therefore, the number of lead pins 24 can be reduced.

As described later, it is difficult to dispose the temperature adjustment element 12, the light receiving elements 37 and 38 outside the base 10. On the other hand, even if the thermistor 40 is provided outside the base 10, the temperature can be detected. That is, the temperature inside the pedestal 10 can be approximately calculated based on the temperature of the side wall 10a detected by the thermistor 40. Thus, the temperature can be detected. Also, the increase in the number of lead pins 24 can be suppressed.

The feedthrough 20 protrudes from the sidewall 10a of the base 10 to the outside of the base 10. Lead pins 24 are disposed on the surface of feedthrough 20 outside of base 10. The thermistor 40 is disposed outside the base 10, and may be disposed on a wall surface other than the side wall 10 a. However, when the flexible substrate 70 is long, the structure may be complicated. Therefore, it is preferable that the thermistor 40 be provided on the side wall 10a and the feedthrough 20. When the flexible substrate 70 faces the side wall 10a, the flexible substrate 70 is electrically connected to the lead pins 24 and the thermistor 40. Therefore, the structure can be simple.

The pads 74 and the wirings 76 are provided on the surface 70a of the flexible substrate 70. When the face 70a faces the side wall 10a and the flexible substrate 70 is connected to the lead pins 24, the electrodes 42 of the thermistor 40 are connected to the pads 74 and the wirings 76. The wiring 78 of the face 70b is connected to the lead pin 24 via the through-hole electrode 72. Accordingly, the optical semiconductor device 100 can be electrically connected to an external component via the flexible substrate 70.

As illustrated in fig. 5, the wavelength tunable laser element 30 includes electrodes 56 and 66 and heaters 58a and 58 b. The plurality of lead pins 24 include lead pins connected to the electrodes and the heater. Therefore, the number of the lead pins 24 is large. However, the number of lead pins 24 is large, and it may be difficult to downsize the optical semiconductor device 100. In the first embodiment, the thermistor 40 is disposed outside the base 10. Therefore, the lead pin 24 is not connected to the thermistor 40. Therefore, the increase in the number of the lead pins 24 can be suppressed. Also, it is possible to downsize the optical semiconductor device 100. The wavelength tunable laser element 30 may include an SG-DFG region as a gain region instead of the TDA-DFB region. The wavelength tunable laser element 30 may include a SG-DBR region as a reflective region instead of the CSG-DBR region.

When the temperature adjustment element 12 is disposed outside the base 10, temperature control of the wavelength tunable laser element 30 may be difficult. Therefore, it is preferable that the temperature adjustment element 12 is installed inside the base 10. In this case, a part of the lead pin 24 is connected to the electrode 13 of the temperature adjustment element 12. In the first embodiment, the temperature adjustment element 12 is housed inside the base 10. Also, the thermistor 40 is disposed outside the base 10. Therefore, temperature control is possible by using the temperature adjustment element 12. Also, the increase in the number of lead pins 24 is suppressed.

When the light receiving elements 37 and 38 receive light, the light receiving elements 37 and 38 output current. The wavelength of the wavelength tunable laser element 30 may be controlled based on the current. Therefore, it is preferable that the light receiving elements 37 and 38 are housed together with the wavelength tunable laser element 30 inside the base 10. In this case, a part of the lead pin 24 is connected to the electrode 13 of the temperature adjustment element 12. In the first embodiment, the light receiving elements 37 and 38 are accommodated inside the base 10, and the thermistor 40 is provided outside the base 10. Therefore, the wavelength can be controlled by using the light receiving elements 37 and 38. The increase in the number of the lead pins 24 is suppressed.

Second embodiment

The positions of the lead pins 24 of the second embodiment are different from those of the first embodiment. Fig. 6A illustrates a cross section of the optical semiconductor device of the second embodiment. Fig. 6B illustrates a front view of the optical semiconductor device 200, and enlarges the vicinity of the feedthrough 20 and the thermistor 40. As illustrated in fig. 6A and 6B, a step is formed in a portion of the feedthrough 20 outside the base 10. Each lead pin 24 is provided on each step.

Fig. 7A and 7B illustrate front views of the case where the flexible substrate 70 is connected to the lead pins 24. Fig. 7A illustrates one side of the face 70 a. Fig. 7B illustrates one side of the face 70B. As illustrated in fig. 7A and 7B, two columns of the through-hole electrodes 72 are provided in accordance with the lead pins 24. As illustrated in fig. 7A, the thermistor 40 is below the through-hole electrode 72. The electrode 42 is connected to the pad 74. As illustrated in fig. 7B, the wiring 78 connected to the via electrode 72 is provided on the face 70B. The other structure is the same as that of the first embodiment.

As in the first embodiment, in the second embodiment, the lead pin 24 is not connected to the thermistor 40. Therefore, the number of lead pins 24 is suppressed from increasing. Also, the temperature may be detected by the thermistor 40.

Third embodiment

Fig. 8 illustrates a front view of a case where the flexible substrate 70 is connected to the lead pins 24, and illustrates one side of the face 70 a. As illustrated in fig. 8, wirings 76 and 78 are provided on the face 70 a. The wiring 78 is bent. Thus, the wiring 78 does not overlap the thermistor 40. The wiring 78 is not connected to the pad 74 and the wiring 78. When the face 70a of the flexible substrate 70 faces the submount 10, the electrode 42 is connected to the pad 74. Also, the lead pin 24 is connected to the wiring 78. The other structures are the same as those of the first embodiment or the second embodiment.

As in the first embodiment, in the third embodiment, the lead pin 24 is not connected to the thermistor 40. Therefore, the number of lead pins 24 is suppressed from increasing. Also, the temperature may be detected by the thermistor 40.

As in the case of the first to third embodiments, the position of the via electrode 72 is determined in accordance with the position of the lead pin 24. Further, the layout of the wirings 76 and 78 is adjusted. Therefore, the optical semiconductor device can be controlled by using the flexible substrate 70. The terminals for the external components may not necessarily be lead pins. A sensor other than the thermistor 40 may be used as the temperature detection portion.

Although the embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and alterations can be made hereto without departing from the spirit and scope of the invention.

Description of letters or numerals

10 base

10a side wall

12 temperature regulating element

13. 42, 56, 66 electrodes

14 vectors

15. 17, 22 wiring pattern

16 chip carrier

18 window

20 feed-through

24 lead pin

25. 26 bonding wire

30-wavelength tunable laser element

32 lens

34. 36 beam splitter

37. 38 light receiving element

39 etalon

40. 41 thermistor

50 base plate

Lower cladding layer 51

52 active layer

53 optical waveguide layer

54 upper coating layer

55 contact layer

57 insulating film

58A, 58b heater

59 power supply electrode

60 ground electrode

61 counter electrode

62. 63 facet Membrane

64 light amplifying layer

67 diffraction grating

70 flexible substrate

70A, 70b side

72 through hole electrode

74 bonding pad

76. 78 wiring

100,200 optical semiconductor device