JP2001094193A - Semiconductor laser with modulator and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce reflectivity of a laser beam on the end surface of a semiconductor laser having an external light modulation mechanism. SOLUTION: When a window region for reducing the reflection of a laser beam on the emitting end surface of a semiconductor laser is formed for making the fluctuations of the oscillation wavelength of the laser beam at application of a modulation voltage suppress and for making a leakage current suppress, the side of an active layer is formed separately from the window structure of the window region. By utilizing an integrated light source, which is formed by the above method and has an external light modulation function, the leakage current can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor laser and a method for manufacturing the same, and more particularly, to a semiconductor laser having an optical modulation function and a method for manufacturing the same.

[0002]

2. Description of the Related Art At present, a modulator-integrated light source has attracted attention as a light source for a long-distance, large-capacity communication system because of its small wavelength chirping during modulation and easy downsizing.
Conventionally, regarding a modulator integrated semiconductor laser, there has been a method of creating a window structure region for reducing end face reflectance and reducing wavelength fluctuation due to reflected return light. Such a method is described, for example, in Yamazaki et al., “Study of Low Voltage and High Power in DFB-LD / Modulator Integrated Light Source”, IEICE Technical Report LQE
95-18 (1995-06). FIG. 3 shows a conventional device structure. FIG. 3A is a perspective view of a conventional element structure. The n-type InP substrate 201
Laser region 21 having grating 202 on substrate
4, a modulator area 215 and a window area 216.
The n-type InP substrate 201 has a waveguide 205 and a waveguide 2
05, a mesa ridge waveguide 204 having an active layer therein,
-InP cladding layer 208. The laser region p-side contact electrode 210, the modulation region p-side contact electrode 211, the n-side contact electrode 212, and the low reflection film 213 are provided. FIG. 3B shows the window region 21.
6 is a cross-sectional view near the ridge waveguide 205 of FIG. p-In
The window region 216 is buried in the P cladding layer 208. In this embedding process, the p-InP cladding layer 208 is also formed on the side wall of the mesa ridge waveguide 204 having the active layer.

[0003]

However, when the window region is buried in the cladding layer and grown, the side wall of the ridge waveguide is grown simultaneously with the window region. To form Therefore, the electric capacity was large. Further, when laser oscillation is performed, there is a problem that a leak current is generated via the p-InP cladding layer 208 on the side wall.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method for manufacturing a semiconductor laser device, comprising the steps of: The electric capacity can be reduced by separating the step of burying the region. Further, since no cladding layer is formed on the side wall of the ridge waveguide, the leakage current can be reduced.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described. FIG. 1 is a perspective explanatory view showing the structure of the element of the first embodiment. As illustrated, the n-type InP substrate 101 includes a laser region 117, a modulator region 118, and a window region 119 on the substrate. The inverted mesa ridge waveguide 111, the polyimide 112, the low reflection film 116 on the side surface on the side of the window region 119, and the p-InP clad layer 10
8 and a p-InGaAs contact layer 109 are provided. P-In is also applied to the inverted mesa ridge waveguide 111 part.
A P cladding layer 108 and a p-InGaAs contact layer 109 are provided.

A p-side contact electrode 113 for a laser region in the waveguide portion of the laser region 117, a p-side contact electrode 114 for the modulation region in a waveguide portion of the modulation region 118, and n
N-side contact electrode 115 on the bottom of
And are provided.

Hereinafter, a method of manufacturing the device according to the first embodiment will be described with reference to FIGS. First, as shown in FIG. 4, an n-type InP substrate 10 having a (100) plane orientation is used.
First, a laser area 117, a modulator area 118, and a window area 119 of a DFB (Distributed Bragg Reflector) laser are continuously determined under predetermined conditions. The grating 102 having a predetermined period and a predetermined depth is formed in the laser region 117 in the <011-> direction. (In this specification, 1- represents bar 1.)
A pair of selective growth masks 1 is
03 is formed. The width of the mask 103 is 20 to 40 μm
And the interval between the two masks 103 is 2 to 30 μm.
m. Here, it is assumed that the width of the mask 103 and the interval between the two masks 103 are appropriately optimized in order to obtain a film growth condition by a film forming apparatus to be used and a desired design structure.

Next, as shown in FIG.
The buried layer 140, the InGaAsP / InGaAsP multiple quantum well layer 141, and the p-InP cladding layer 106 are selectively grown using metal organic chemical vapor deposition (MOVPE).

Here, the InGaAsP buried layer 140
And InGaAsP / InGaAsP multiple quantum well layer 14
1 and the thickness of the p-InP cladding layer 106 are
18 and the window region 119 are designed and formed to have an optimum structure, and the laser region 117 is formed to be thicker than the modulation region 118 by designing a selective growth mask.

Next, as shown in FIG. 6, an insulating film mask 107 is formed on the p-InP cladding layer 106 by photolithography and etching. The insulating film mask 107 is formed using silicon oxide. At this time, the insulating film mask 107 is formed in parallel with the selective growth mask 103, and is formed between the two masks 103. The width of the insulating film mask 107 is about 5 to 20 μm. The planar shape is a rectangular shape. This corresponds to a portion forming the ridge waveguide portion of the device of the first embodiment. Therefore, the insulating film mask 107 is not formed in the window region 119.

Next, as shown in FIG. 7, etching is performed using the insulating film mask 107 as an etching mask.
Grating 102 and InG
aAsP buried layer 140 and InGaAsP / InG
The aAsP multiple quantum well layer 141 and the p-InP cladding layer 106 are removed. Therefore, the insulating film mask 107
Below, an island-shaped mesa structure 105 can be formed. The island-shaped mesa structure 105 includes the grating 102, the InGaAsP buried layer 140, and the InGaAsP / I
It is formed of an nGaAsP multiple quantum well layer 141 and a p-InP cladding layer 106. At this time, InGaAs
In the sP / InGaAsP multiple quantum well layer 141, the one formed in the modulation region 118 is used as the absorption layer 401, and the one formed in the laser region 117 is used as the active layer 402.
Use as Next, the insulating mask 107 is removed.

Next, as shown in FIG. 8, a p-InP cladding layer 108 and a p-InGaAs contact layer 109 are sequentially grown by metal organic chemical vapor deposition (MOVPE). At this time, the island-shaped mesa structure 105 is formed so as to be embedded. Specifically, the p-InP cladding layer 10
In step 8, the island-shaped mesa structure 105 is buried. p-InP
The film thickness of the clad layer 108 is formed to be 1.5 μm to 2 μm higher than the height of the island-shaped mesa structure 105. Next, pI is formed on the entire surface of the p-InP cladding layer 108.
An nGaAs contact layer 109 is formed. Next, an insulating film mask 110 is formed on the p-InGaAs contact layer 109.
Formed on the entire upper surface.

Next, as shown in FIG. 9, a part of the insulating film mask 110 corresponding to the island-shaped mesa structure 105 buried earlier is removed by photolithography and etching. However, 10 μm before the window area
The degree is left without being removed. More specifically, it becomes a pair of rectangular shapes parallel to the embedded island-shaped mesa structure 105.
The interval between the two parts to be removed is about 2 μm to 4 μm.

Next, as shown in FIG. 10A, using the insulating film mask 110 as an etching mask, the contact layer 109 and a part of the p-InP cladding 108 are etched by dry etching.

Next, selective etching is performed using an acetic acid-based etchant. At this time, the island-shaped mesa structure portion 105 described above is etched to form a ridge waveguide having an inverted mesa structure. This is called an inverted mesa ridge waveguide 111. FIG. 10B is a cross-sectional view of the inverted mesa ridge waveguide 111 in the laser region. The width of the top of the inverted mesa ridge waveguide 111 is about 2 μm to 4 μm. At the time of selective etching, the InGaAsP / InGaAsP multiple quantum well layer 141 formed of a quaternary mixed crystal composition
Is used as an etching stop layer. At this time, no waveguide having the InGaAsP / InGaAsP multiple quantum well layer 141 is formed in the window region 119. Also,
Two grooves formed by etching on both sides of the inverted mesa ridge waveguide 111 are called double channels.

As described above, when the width of the island-shaped mesa structure portion 105 is set to about 20 μm by the design of the insulating film mask 107, the width 150 of the double channel becomes equal to that of the island-shaped mesa structure portion 1.
05 is smaller than 20 μm in width. The double channel is formed in the window region about 10 μm longer than the island-shaped mesa structure 105.

Next, the insulating film mask 110 is removed. Next, the laser region 117 and the modulator region 118 are electrically separated. For this purpose, the boundary between the two regions should be between 1 μm and 20 μm.
P-InGaAs contact layer 10 having a width of about 00 μm
9 is removed.

Next, as shown in FIG. 11, the double channel is embedded with polyimide 112. Next, as shown in FIG. 1, a laser region p-side contact electrode 113 is formed by vapor deposition on the reverse mesa ridge waveguide 111 of the laser region 117, and a modulation region is formed on the reverse mesa ridge waveguide 111 of the modulation region 118. P-side contact electrode 114 is formed by evaporation,
An n-side contact electrode 115 is formed by vapor deposition on a portion corresponding to the lower side of the n-type InP substrate 101. Here, the p-side contact electrode uses AuZn laminated on AuZn, and the n-side electrode uses AuGeNi.

Next, the electrodes are alloyed by an annealing step, and are cleaved into devices of a desired size. Next, the window area 11
The low-reflection film 116 is coated on the end surface on the ninth side. Here, SiOx or the like is used for the low reflection film. The length of each region after chip formation is 300 μm for the laser region 117.
m to about 700 μm, the modulator area 118 is about 50 to 250 μm, and the window area 119 is about 10 to 50 μm.

In the method of driving the modulator integrated semiconductor laser manufactured in the first embodiment, a forward current is injected into the active layer to cause laser oscillation in a single mode. At this time, the drive current depends on the laser characteristics at the time of design and the structure of the modulator.
A light output of 2 to 5 mW is obtained by injecting about 0 to 100 mA. Next, a modulated signal can be obtained by applying a reverse voltage of about 0.5 to -3 V to the modulator region 118. At this time, the modulation voltage is 0.5 to -0.5 V
When high, light output is obtained. The modulation voltage is-
When the voltage is as low as 2.5 to -3 V, no light output is obtained.

As described above, since the p-InP cladding layer 108 formed on the side wall of the inverted mesa ridge waveguide 111 is removed by forming the first embodiment, the leakage current is reduced, and the laser characteristics are reduced. Degradation can be suppressed.

Next, a second embodiment will be described.
FIG. 2 is a perspective explanatory view showing the structure of the element of the second embodiment.

As shown, an n-type InP substrate 301
Is a laser region 318 and a modulator region 319 on a substrate.
And a window region 320. An inverted mesa ridge waveguide 312, a polyimide 313, a low reflection film 317 on the side surface on the window region 320 side, a p-InP cladding layer 309,
A p-InGaAs contact layer 310 is provided. The p-InP cladding layer 308 and the p-InGaAs contact layer 310 are also provided in the inverted mesa ridge waveguide 312 part.
Are provided.

A p-side contact electrode 314 for the laser region in the waveguide portion of the laser region 318, a p-side contact electrode 315 for the modulation region in the waveguide portion of the modulation region 319, and n
N-side contact electrode 316
And are provided.

Hereinafter, a method of manufacturing the device according to the second embodiment will be described with reference to FIGS.

First, as shown in FIG.
00) n-type InP substrate 301 with a DFB (Distributed
A laser region 318, a modulator region 319, and a window region 320 of a Bragg reflector (laser) laser are continuously determined under predetermined conditions. The grating 302 having a predetermined period and a predetermined depth is formed in the laser region 318 in the <011-> direction. Next, the laser region 3 with the grating 302
18, a pair of selective growth masks 303 is formed. The width of the mask 303 is about 20 to 40 μm, and the interval between the two masks 303 is about 2 to 30 μm. Here, the width of the mask 303 and the interval between the two masks 303 are appropriately optimized in order to obtain a film growth condition by a film forming apparatus to be used and a desired design structure.

Next, as shown in FIG.
P buried layer 340 and InGaAsP / InGaAsP
The multiple quantum well layer 341 and the p-InP cladding layer 306 are selectively grown using metal organic chemical vapor deposition (MOVPE). Here, the InGaAsP buried layer 340 and I
The film thickness of the nGaAsP / InGaAsP multiple quantum well layer 341 and the p-InP cladding layer 306 is
The window region 320 is designed and formed to have an optimum structure. In the laser region 318, the modulation region 31
It is formed thicker than 9.

Next, as shown in FIG. 14, an insulating film mask 307 is formed on the p-InP cladding layer 306 by photolithography and etching. The insulating film mask 307 is formed using silicon oxide. At this time,
The insulating film mask 307 is formed in parallel with the selective growth mask 303, and is formed between the two masks 303. The width of the insulating film mask 307 is about 5 to 20 μm. The planar shape is a rectangular shape. This corresponds to a portion forming a ridge waveguide portion of the device of the second embodiment. Therefore, the insulating film mask 307 is not formed in the window region 320.

Next, as shown in FIG. 15, etching is performed using the insulating mask 307 as an etching mask. The p-InP cladding layer 306 and I
nGaAsP / InGaAsP multiple quantum well layer 341
And the InGaAsP buried layer 340 and the grating 302 are removed. Therefore, the insulating film mask 307
Below, an island-shaped mesa structure 305 can be formed. At this time, of the InGaAsP / InGaAsP multiple quantum well layer 341, the one formed in the modulation region 319 is used as the absorption layer 401, and the one formed in the laser region 318 is used as the active layer 402.
As shown in FIG. 5, an i-InP block layer 308 for blocking a current is formed on a portion other than the island-shaped mesa structure portion 305 by metal organic chemical vapor deposition (MOVPE). Specifically, a film is formed to the same height as the island-shaped mesa structure portion 305. Next, the insulating mask 307 on the island-shaped mesa structure 305 is removed by etching.

Next, as shown in FIG. 17, a p-InP cladding layer 309 and a p-InGaAs contact layer 310 are sequentially grown by metal organic chemical vapor deposition (MOVPE). At this time, the p-InP cladding layer 309 is formed to have a thickness of 1.5 μm to 2 μm. Next, p-InGaAs is formed on the entire surface of the p-InP cladding layer 308.
The s-contact layer 310 is formed. Next, an insulating film mask 311 is formed on the entire surface of the p-InGaAs contact layer 310.

Next, as shown in FIG. 18, a portion of the insulating film mask 311 corresponding to the portion corresponding to the island-shaped mesa structure 305 buried earlier is removed by photolithography and etching. However, about 10 μm before the window area is left without being removed. For more information,
It becomes a pair of rectangular shapes parallel to the embedded island-shaped mesa structure 305. The interval between the two parts to be removed is about 2 μm to 4 μm.

Next, as shown in FIG. 19A, using the insulating film mask 311 as an etching mask, the contact layer 310 and a part of the p-InP cladding layer 308 are etched by dry etching. Next, selective etching is performed using an acetic acid-based etchant. At this time, the above-mentioned island-shaped mesa structure portion 305 is etched to form a ridge waveguide having an inverted mesa structure. This is called an inverted mesa ridge waveguide 312. FIG. 19B is a cross-sectional view of the island-shaped mesa structure 305 in the laser region 318. The width of the top of the inverted mesa ridge waveguide 312 is about 2 μm to 4 μm. At the time of selective etching, InGaAs formed by a quaternary mixed crystal composition
The P / InGaAsP multiple quantum well layer 341 is used as an etching stop layer. At this time, the window region 320 includes the InGaAsP / InGaAsP multiple quantum well layer 341.
Is not formed. Two grooves formed by etching on both sides of the inverted mesa ridge waveguide 312 are called double channels.

As described above, when the width of the island-shaped mesa structure portion 305 is set to about 20 μm by the design of the insulating film mask 307, the width 350 of the double channel becomes equal to the island-shaped mesa structure portion 3.
05 is smaller than 20 μm in width. The double channel is longer than the island-shaped mesa structure portion 305 by about 10 μm in the window region. Next, the insulating film mask 311 is removed.
Next, the laser region 318 and the modulator region 319 are electrically separated. Therefore, the p-InGaAs contact layer 3 having a width of about 20 μm to 100 μm
10 is removed.

Next, as shown in FIG. 20, the double channel is embedded with polyimide 313. Next, as shown in FIG. 2, a laser region p-side contact electrode 314 is formed by vapor deposition on the inverted mesa ridge waveguide 312 portion of the laser region 318, and the modulation region is formed on the inverted mesa ridge waveguide 312 portion of the modulation region 319. P-side contact electrode 315 is formed by evaporation,
An n-side contact electrode 316 is formed by vapor deposition on a portion corresponding to the lower side of the n-type InP substrate 301. Here, the p-side contact electrode uses AuZn laminated on AuZn, and the n-side electrode uses AuGeNi.

Next, the electrodes are alloyed by an annealing step, and are cleaved into devices of a desired size. Next, the window area 32
The low-reflection film 317 is coated on the end surface on the 0 side. Here, SiOx is used for the low reflection film. The length of each area after chip formation is 300 μm for the laser area 318.
Modulator region 319 is approximately 50 μm to 250 μm, and window region 320 is approximately 10 μm to 50 μm.
It is about μm.

The method of driving the modulator integrated semiconductor laser manufactured in the second embodiment is performed in the same manner as in the first embodiment. At this time, depending on the laser characteristics at the time of design and the structure of the modulator, the drive current is about 50 mA to 100 mA, and an optical output of 2 to 5 mW is obtained. Next, a modulated signal can be obtained by applying a reverse voltage of about 0.5 to -3 V to the modulator region 319. At this time, when the modulation voltage is as high as about 0.5 to -0.5 V, an optical output is obtained. When the modulation voltage is as low as -2.5 to -3V,
No light output is obtained.

Thus, the i-In for blocking the current
By forming the P block layer 308, the leakage current to the window region can be further reduced, the electric capacity is also reduced, and the deterioration of laser characteristics and modulation signal light can be suppressed.

The present invention is not limited to the above embodiment. For example, in the first embodiment, the modulator integrated DFB laser is formed by using the selective growth method.
It is also possible to use a butt joint in which a modulator region is created. Further, although InP is used as a block layer for containing current, the present invention is not limited to this, and any intrinsic semiconductor can be used.

In the first embodiment, the window region integrated laser is described using an InP-based material. However, any other material based on the same structure can be applied. In the first embodiment, the structure with the window region of the modulator integrated DFB laser has been described. However, a multifunctional device integrated laser formed with a ridge waveguide structure with a window region integrated with other functions is described. Is also applicable.

In this embodiment, the active layer is formed with a quaternary mixed crystal composition and used as an etching stop layer. However, an etching stop layer is formed below the active layer, and the active layer is etched. It is possible to remove it.

In this embodiment, the groove of the double channel is buried with polyimide. However, other than the polyimide, any photosensitive dielectric may be used.

[0042]

By forming the window structure as described above in detail, it is possible to further reduce the leak current and suppress the fluctuation of the laser wavelength by the residual reflectance at the end face. Further, the electric capacity is also reduced, so that the deterioration of the modulation operation characteristics can be suppressed. In addition, by introducing the current blocking layer, the leak current can be further reduced, the electric capacity can be reduced, and the deterioration of the operation characteristics can be suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an element of a first embodiment.

FIG. 2 is a perspective view showing an element of a second embodiment.

FIG. 3 is a diagram showing a conventional element structure.

FIG. 4 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 5 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 6 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 7 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 8 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 9 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 10 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 11 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 12 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 13 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 14 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 15 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 16 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 17 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 18 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 19 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

FIG. 20 is a manufacturing process diagram of a semiconductor laser having a light modulation function according to the present invention.

[Explanation of symbols]

101, 201, 301 InP substrate 102, 202, 302 Grating 103, 303 Selective growth mask 106, 108, 208, 306, 309 p-InP
Cladding layer 308 i-InP block layer 107, 110, 307, 311 Insulating film mask 109, 310 p-InGaAs contact layer 113, 211, 314 P-side contact electrode for laser region 114, 210, 315 P-side contact electrode for modulation region 115, 212, 316 n-side contact electrode 117, 214, 318 Laser region 118, 215, 319 Modulation region 119, 216, 320 Window region 141, 341 InGaAsP / InGaAsP multiple quantum well layer 111, 312 Inverted mesa ridge waveguide 204 Active layer 112, 313 polyimide 140, 340 InGaAsP buried layer 105, 305 Island-shaped mesa structure 205 Waveguide 150, 350 Double channel width 401 Absorption layer 402 Active layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H079 AA02 AA13 BA01 CA05 DA16 EA03 EA21 EA27 HA15 JA07 KA18 5F073 AA23 AA64 AA74 AA83 AA87 AA89 CA12 CB02 DA05 DA23 DA24 EA03 EA28

Claims (10)

[Claims] A semiconductor laser with a modulator in which a laser region, a modulator region, and a window region of only a cladding layer without an absorption layer are formed on the same substrate at an end surface of the modulator region in the light emission direction. 2. The semiconductor laser with a modulator according to claim 1, wherein both sides of the ridge waveguide portion formed in the laser region and the modulation region are formed of a dielectric. 2. A semiconductor laser with a modulator, wherein a laser region, a modulator region, and a window region of only a cladding layer without an absorption layer are formed on the same substrate at an end face of the modulator region in the light emission direction. Wherein both sides of a ridge waveguide portion formed in the laser region and the modulation region are formed of a dielectric, and the cladding layer of the window region is formed of an intrinsic semiconductor. Semiconductor laser with a modulator. 3. A semiconductor laser with a modulator, wherein a laser region, a modulator region, and a window region of only a cladding layer without an absorption layer are formed on the same substrate at an end face in the light emitting direction of the modulator region. Forming a mesa structure portion having an active layer and an absorption layer in the laser region and the modulator region on the substrate; and cladding at least an extension of the mesa structure portion to the window region. A step of forming a layer, a step of sequentially forming a cladding layer and a contact layer on at least the mesa structure portion, and a rectangular shape for forming a ridge waveguide portion on a portion corresponding to the mesa structure portion on the contact layer. Forming an insulating film mask on the
Using the insulating mask as an etching mask to remove the cladding layer and the contact layer by etching to form the ridge waveguide portion. 4. A semiconductor laser with a modulator, wherein a laser region, a modulator region, and a window region of only a cladding layer without an absorption layer are formed on the same substrate at an end face of the modulator region in the light emission direction. Forming a mesa structure having an active layer and an absorption layer in the laser region and the modulator region on the substrate; and forming an intrinsic semiconductor at least in an extension of the mesa structure to the window region. A step of forming a layer, a step of sequentially forming a cladding layer and a contact layer on at least the mesa structure, and forming a ridge waveguide portion on a portion corresponding to the mesa structure by forming a rectangle on the contact layer. Forming an insulating film mask in the shape, using the insulating mask as an etching mask,
Forming the ridge waveguide portion by removing the contact layer and the clad layer by etching. 5. A semiconductor laser with a modulator, wherein a laser region, a modulator region, and a window region of only a cladding layer without an absorption layer are formed on the same substrate at an end face of the modulator region in the light emission direction. Forming a mesa structure having an active layer and an absorption layer in the laser region and the modulator region on the substrate; and forming a cladding layer in the laser region, the modulator region, and the window region. Forming a cladding layer and a contact layer sequentially on the mesa structure portion; and forming a ridge waveguide portion on a portion corresponding to the mesa structure portion to form a rectangular shape on the contact layer. Forming an insulating film mask, and using the insulating mask as an etching mask, removing the contact layer and the cladding layer by etching to form the ridge waveguide portion. Method for producing a modulator integrated semiconductor laser and having the steps of, a. 6. A semiconductor laser with a modulator in which a laser region, a modulator region, and a window region of only a cladding layer without an absorption layer are formed on the same substrate at an end face of the modulator region in the light emission direction. Forming a mesa structure having an active layer and an absorption layer in the laser region and the modulator region on the substrate; and forming an intrinsic semiconductor in the laser region, the modulator region, and the window region. Forming a layer;
Forming a cladding layer and a contact layer sequentially on the mesa structure portion, and forming a rectangular insulating mask on the contact layer to form a ridge waveguide portion on a portion corresponding to the mesa structure portion. And a step of forming the ridge waveguide portion by removing the contact layer and the clad layer by etching using the insulating mask as an etching mask to form the ridge waveguide portion. Manufacturing method. 7. A semiconductor laser with a modulator, wherein a laser region, a modulator region, and a window region of only a cladding layer without an absorption layer are formed on the same substrate at an end face of the modulator region in the light emission direction. Forming a mesa structure portion having an active layer and an absorption layer in the laser region and the modulator region on the substrate; and cladding at least an extension of the mesa structure portion to the window region. A step of forming a layer, a step of sequentially forming a cladding layer and a contact layer on at least the mesa structure portion, and a rectangular shape for forming a ridge waveguide portion on a portion corresponding to the mesa structure portion on the contact layer. Forming an insulating film mask on the
Using the insulating mask as an etching mask, using the active layer as an etching stop layer, and etching away the cladding layer and the contact layer to form the ridge waveguide portion. A method for manufacturing a semiconductor laser with a modulator. 8. A semiconductor laser with a modulator in which a laser region, a modulator region, and a window region of only a cladding layer without an absorption layer are formed on the same substrate at an end face of the modulator region in the light emission direction. Forming a mesa structure having an active layer and an absorption layer in the laser region and the modulator region on the substrate; and forming an intrinsic semiconductor at least in an extension of the mesa structure to the window region. A step of forming a layer, a step of sequentially forming a cladding layer and a contact layer on at least the mesa structure, and forming a ridge waveguide portion on a portion corresponding to the mesa structure by forming a rectangle on the contact layer. Forming an insulating film mask in the shape, using the insulating mask as an etching mask,
Forming the ridge waveguide by removing the contact layer and the cladding layer by etching using the active layer as an etching stop layer. . 9. A semiconductor laser with a modulator, wherein a laser region, a modulator region, and a window region of only a cladding layer without an absorption layer are formed on the same substrate at an end face of the modulator region in the light emission direction. Forming a mesa structure having an active layer and an absorption layer in the laser region and the modulator region on the substrate; and forming a cladding layer in the laser region, the modulator region, and the window region. Forming a cladding layer and a contact layer sequentially on the mesa structure portion; and forming a ridge waveguide portion on a portion corresponding to the mesa structure portion to form a rectangular shape on the contact layer. Forming an insulating film mask, and using the insulating mask as an etching mask, using the active layer as an etching stop layer, and etching the contact layer and the cladding layer. Method for producing a modulator integrated semiconductor laser and having a step of forming the ridge waveguide section is removed by quenching. 10. A semiconductor laser with a modulator in which a laser region, a modulator region, and a window region of only a cladding layer without an absorption layer are formed on the same substrate at an end face of the modulator region in the light emission direction. Forming a mesa structure having an active layer and an absorption layer in the laser region and the modulator region on the substrate; and forming an intrinsic semiconductor in the laser region, the modulator region, and the window region. Forming a layer, sequentially forming a cladding layer and a contact layer on the mesa structure portion, and forming a ridge waveguide portion on a portion corresponding to the mesa structure portion to form a rectangular shape on the contact layer. Forming an insulating film mask on the contact layer and the cladding layer using the active layer as an etching stop layer using the insulating mask as an etching mask. Method for producing a modulator integrated semiconductor laser and having a step of forming the ridge waveguide portion is removed by etching.