JP2967757B2 - Semiconductor laser device and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device, and more particularly to a high-power semiconductor laser suitable for use in optical communication, optical measurement light sources, fiber amplifiers, solid-state laser excitation light sources, and information processing. The present invention relates to an apparatus and a method of manufacturing the same .

[0002]

2. Description of the Related Art Documents related to a semiconductor laser device include, for example, those described below. (1) JP-A-4-136824. (2) Kenichi Iga, Semiconductor Laser, Ohmsha, Oct. 25, 1994, pp. 242-247.

A semiconductor laser device having a Fabry-Perot type resonator has a long cavity, reduces the injection current density,
When the heat generation is suppressed and the reflectivity of the end face of the resonator is made asymmetric, a high optical output can be obtained when a high current is injected. Therefore, it is used for applications where the optical output is more important than the spectral shape.

Among them, a Fabry-Perot cavity semiconductor laser device using an InGaAsP / InP-based material is known as an OTDR (Opt) used for detecting a break point of a converter.
ical Time Domain Reflect
1.3) of light output of 150 mW or more for
Used as 1.55 μm band high power laser,
2. Description of the Related Art High-power lasers in the 1.48 μm band have attracted attention as light sources for pumping optical fiber amplifiers due to recent increases in capacity and length of optical fiber communication.

Conventionally, this type of high-power semiconductor laser device is disclosed in, for example, the above-mentioned document (2) (published October 25, 1994, “Semiconductor Laser”, pp. 242 to 247). Mesa stripes with active areas
The semiconductor laser device has a long cavity by increasing the size of the semiconductor laser device due to the single stripe structure of one linear waveguide, and the reflectance of the cavity end face is asymmetric.

FIG. 7 is a perspective view for explaining the configuration of a general high-power semiconductor laser device. As shown in FIG. 7, the waveguide has a long-resonator structure with a single stripe structure, and one end face has a low reflection film (AR film: Anti-Ref).
In other words, the other end face is a high reflection film (HR film: High Reflectivity).
on coating) 22, and the reflectance at both end surfaces is asymmetric.

A general method of manufacturing this semiconductor laser device is to form an n-type cladding layer 12 composed of InP, an active layer 13 composed of InGaAsP, and a p-type cladding layer composed of InP on an n-type InP substrate 11 by, for example, an organic method. The layers are stacked by metal vapor deposition (MOVPE).

Then, two parallel mesa grooves 23 are formed by wet etching in the resonator direction to form a single stripe structure having cladding layers 12 and 14 above and below the active layer 13.

Furthermore, LPE growth (Liquid Phase Epitaxi) in which no crystals grow on the upper surface of the narrow stripes
al growth), the current blocking layer 15 made of p-type InP except for the upper surface of the stripe,
current blocking layer 16 of n-type InP and p-type I
An embedded layer 17 made of nP and an ohmic contact layer 18 made of p-type InGaAs for making ohmic contact with an electrode are formed, and an embedded semiconductor laser resonator having a current blocking layer is formed.

Thereafter, a metal electrode 20 is formed on the n-type InP substrate 11, and a metal electrode 19 is formed on the p-type ohmic contact layer 18.

Subsequently, a high reflection film 22 is formed on one of the end faces formed by the cleavage method.

Further, for example, SiO 2 is provided on the other end face.
_The low reflection film 21 made of ₂ or SiN is formed, and the semiconductor laser device 500 is configured as described above.

Next, the operation principle will be described.

The carrier injected from the electrode 19 is supplied to the active layer 13 between the p-type clad layer 12 and the n-type clad layer 14 through the p-type ohmic contact layer 18 and the p-type buried layer 17 to amplify the laser beam. To form an active medium. The laser beam light generated in the active medium is guided while gaining the waveguide layer of the semiconductor laser device 500, and the light reaches one end face of the resonator. A high-reflection film 22 is formed on one end face of the resonator, whereby light is reflected and returned, and is guided again while gaining the waveguide. A low-reflection film 21 is formed on the other end surface, and a part of the light is emitted to the outside as a high-output laser beam light amplified from the low-reflection film 21 every round trip.

As described above, light is emitted from the semiconductor laser device 50.
If a single linear waveguide of 0 is folded back in a single stripe, the length of the waveguide layer having a gain is L with respect to the resonator length L of the semiconductor laser device 500.

Due to such a structure, in order to obtain a large optical output, a measure is taken to increase the resonator length L of the semiconductor laser device to obtain a sufficient amplification gain. Increasing the resonator length L also has the advantage of lowering the injected current density, suppressing heat generation due to current injection, and lowering the thermal resistance, so that the generated heat can be quickly released to the heat absorber. .

For this reason, a semiconductor laser device requiring high output has a length of about 900 to 1200 μm, which is 200 μm, which is a resonator length of a normal semiconductor laser device.
At present, the length is three times or more than m to 300 μm.

As a countermeasure against such a long cavity, it is not a semiconductor laser, but as a countermeasure in a semiconductor amplifier, for example, Japanese Unexamined Patent Publication No.
No. 6824 proposes a configuration using a V-branch.

More specifically, the above-mentioned Japanese Patent Application Laid-open No.
Japanese Patent Application Laid-Open No. 4 (1999) -1995 discloses a first optical waveguide which is formed from one end face to the other end face in a semiconductor substrate and has a function of receiving supply of light from the one end face and amplifying the light, A reflecting means formed on the other end face of the semiconductor substrate for reflecting the light supplied to the first optical waveguide; and a reflecting means formed in the semiconductor base from one end face to the other end face thereof and reflected by the reflecting means. And a second optical waveguide having a function of receiving supplied light and amplifying this light. The reflectivity R1 of the one end face is preferably set to R1 ≦ 10 ^−4, and the reflectivity R2 of the reflection means formed on the other end face is set to R1 ≦ 10 ^−4.
Is set to 0.3 ≦ R2 ≦ 1.0, and the product R1 × R2 of the reflectance of the both end surfaces is set to R1 × R2 ≦ 10 ⁻⁴ .

The semiconductor laser amplifier proposed in Japanese Patent Application Laid-Open No. 4-136824 is formed in a semiconductor laser amplifier from one end face to another end face, and has first and second optical waveguides having a function of amplifying light. The length of the optical waveguide layer having a function of amplifying the light by reflecting the light guided through the first optical waveguide by the reflection means and guiding the light through the second optical waveguide. Can be about twice as long as the resonator length, and a large amplification gain can be obtained with a short resonator.

FIG. 8 is a perspective view showing a configuration of a semiconductor laser amplifier described as an embodiment in the above-mentioned Japanese Patent Application Laid-Open No. 4-136824. As shown in FIG. 8, on an n-type InP substrate 11, an active layer 13, a p-type InP cladding layer 14, and a p-type InGa
The AsP ohmic contact layer 18 is formed in a V-shape when viewed from above.

On the side of the active layer 13, the p-type cladding layer 14, and the p-type ohmic contact layer 18, a p-type InP burying layer 15 for narrowing current and light is formed. Semiconductor laser amplifier 50
1 is configured.

Electrodes 19 and 20 are formed on the front and back surfaces of the laser amplifier 501, respectively. These electrodes 19,
Due to the current injection from 20, the optical waveguide layer generates an optical amplification gain.

A low reflection film 21 is formed on one end surface of the laser amplifier 501, and a high reflection film 22 is formed on the other end surface. The reflectivity of the low-reflection film 21 at the end face of the optical waveguide layer is adjusted to the order of 10 ⁻⁴ or less, and the reflectivity of the high-reflection film 22 is set in the range of 0.3 to 1.0. Have been. By adjusting the product of these reflectances to be on the order of 10 ⁻⁴ or less, laser oscillation is suppressed, and the laser amplifier 501 operates as a traveling-wave laser amplifier.

However, in the case of this proposal, R1 × R2 ≦
Since the gain is 10 ^-4 , amplification gain can be obtained, but laser oscillation cannot be performed. Therefore, the semiconductor laser device does not operate.

[0026]

As described above,
Conventional high-power semiconductor laser devices capable of laser oscillation
At present, the resonator length is long.

The first problem with the long cavity length is that the heat generated when assembling the semiconductor laser device increases thermal stress due to the size of the semiconductor laser device. This problem will be described in detail below.

In general, a semiconductor laser device uses a heat absorber (heat sink) having a high thermal conductivity and a fusion material (solder) for a semiconductor laser resonator for the purpose of diffusing heat generated in an active layer region. At this time, a stress is applied to the semiconductor laser chip due to a difference in linear thermal expansion coefficient between the material of the chip and the materials of the heat sink and the fusion bonding material.

When current is applied while the stress generated during the assembly is applied to the semiconductor laser crystal, dislocations are introduced from a weak portion of the crystal surface, and the dislocations extend after reaching the active layer. There is a problem that characteristic deterioration occurs due to this.

Further, in extreme cases, heating during assembly,
Cooling causes strong stress, which may cause damage to the semiconductor laser device. In particular, when the difference in linear thermal expansion coefficient between the semiconductor laser crystal and the heat sink material is significant and the semiconductor laser device is larger, this effect becomes significant.

The second problem is poor productivity.

The reason is that, as described in the prior art, in the case of a high-power semiconductor laser device having a single stripe structure, it is necessary to increase the cavity length of the semiconductor laser device, so that the semiconductor laser chip becomes large. Become. For this reason,
The yield of chips per wafer is reduced, leading to an increase in cost.

Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to reduce the length of a resonator in a high-power semiconductor laser device.
Another object of the present invention is to provide a semiconductor laser device capable of preventing characteristic deterioration and damage due to heating, cooling, and the like during assembly.

Another object of the present invention is to provide a semiconductor laser device which can reduce the size of the semiconductor laser device, increase the yield of chips per wafer, reduce the cost, and thereby improve the productivity, and a method of manufacturing the same. It is in.

[0035]

In order to achieve the above object, a semiconductor laser device according to the present invention is a high power semiconductor laser device oscillated by current injection, wherein at least one Y-branch waveguide has a gain. waveguide, is composed of two curved waveguides and two straight waveguides, wherein
A first high reflection film is provided on the end surface of the Y-branch waveguide before branching.
The other end face has a low-reflection film consisting of a dielectric single-layer film.
And a second region formed of a dielectric multilayer film.
A second region on which a highly reflective film is formed .
Area is in contact with a linear waveguide that emits light,
The second region is in contact with a linear waveguide that makes light reflection,
It is characterized by the following.

According to the manufacturing method of the present invention, the waveguide having a gain is constituted by at least one Y-branch waveguide, two curved waveguides and two straight waveguides, and formed by a cleavage method.
Of the end faces obtained, the end face before branching of the Y branch waveguide is
A first highly reflective film, and the other end face is a dielectric single-layer film
A first region in which a low reflection film made of
Second high reflection film formed by forming a dielectric multilayer film on a projection film
And a second region in which is formed, wherein the first region has
A linear waveguide that emits light is in contact with the second region;
Is a semiconductor laser with a straight waveguide that reflects light
A method for manufacturing a device, comprising:
Forming a low-reflection film made of a single-layer film;
Masking the region, forming a dielectric multilayer film in the second region;
And forming .

In the present invention , one of the Y branch waveguides is used.
Having a diffraction grating on a straight waveguide connected to the other branch,
A low-reflection film consisting of a dielectric multilayer film is provided on the end surface on the light emission side.
The configuration may be changed .

[0038]

Embodiments of the present invention will be described below. In a preferred embodiment of the semiconductor laser device according to the present invention, the waveguide having a gain includes at least one Y-branch waveguide, a curved line, and a straight waveguide, and the light emitting end face includes a low reflection film; For the other end faces, a reflection mechanism made of a dielectric multilayer film or Bragg reflection by a diffraction grating is used.

More specifically, in the embodiment of the present invention, a low-reflection film is provided on one branch side at the end surface on the light emission side, and a reflection mechanism is provided on the other branch side so as to face the light emission side end surface. A high reflection film on the other end face.

In the embodiment of the present invention, on the end face on the light emission side, a low reflection film for light emission is provided on one branch side, and a high reflection film is provided on the other branch side. I do.

In the embodiment of the present invention, a diffraction grating is provided on one branch of the Y-branch waveguide, and only a low reflection film is provided on the end face on the light emission side.

In the semiconductor laser device of the present invention configured as described above, in the embodiment, the length of the waveguide having the gain having the function of amplifying light is about twice the length of the resonator. And a large amplification gain can be obtained with a short resonator length.

Therefore, the semiconductor laser device can be miniaturized, and the thermal stress generated due to the difference in linear thermal expansion coefficient between the respective materials due to heating and cooling at the time of assembling into a heat sink can be reduced. Characteristic deterioration and breakage can be suppressed.

Further, since the size of the semiconductor laser device can be reduced, the productivity is improved.

[0045]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

Embodiment 1 A first embodiment of the present invention will be described. FIG. 1 is a perspective view showing a configuration of a first embodiment of the present invention, and FIG. 2 is a view showing a plane cut along a plane A indicated by an arrow in FIG. 1 and 2, 11 is an n-type InP substrate, 12 is an n-type InP cladding layer, 13 is an active layer having a multiple quantum well structure, and 14 is p-type.
Type InP cladding layer, 15 is a p-type InP current blocking layer, 16 is an n-type InP current blocking layer, 17 is a p-type InP
P buried layer, 18 is a p-type ohmic contact layer, 1
Reference numeral 9 denotes a p-type ohmic electrode, 20 denotes an n-type electrode, 21 denotes a low reflection film (AR film), 22 denotes a high reflection film (HR film), 23 denotes a mesa stripe, and 24 denotes a waveguide having a gain. .

Referring to FIGS. 1 and 2, the manufacturing method according to the first embodiment of the present invention will be described below. (001)
In order to form a curved waveguide portion, a branch waveguide portion, and a tapered waveguide portion on an n-type InP substrate 11 having a plane orientation, a growth inhibition portion is patterned with an oxide film using a mask.

Next, an n-type InP cladding layer 12, an active layer 13 composed of multiple quantum wells (MQW), and a p-type InP cladding layer 14 are selectively grown by metal organic vapor deposition (MOVPE). Are laminated to form a mesa stripe 23 having a Y-branch waveguide portion as shown in FIGS.

In the multiple quantum well structure, InGaAsP having a composition wavelength of 1.50 μm at the time of lattice matching and having a compressive strain of 0.45% introduced therein is used as a well layer and has a thickness of 3.85 n.
m, and the number of well layers was 5. The barrier layer is made of InGaAsP having a composition wavelength of 1.20 μm and has a thickness of 7 nm, and the guide layer is made of InGaAsP having a composition wavelength of 1.13 μm and having a thickness of 330 nm.
ement heterostructure (separation type confinement structure).

FIG. 3 is an enlarged plan view showing the region 50 of FIG. Referring to FIG. 3, the Y-branch waveguide unit includes:
Straight waveguide section 34, curved waveguide section 33, branch section 3
2 and a tapered waveguide 31. The growth blocking mask width W was adjusted at each portion during selective growth so that gains depending on the thickness of the well of the active layer become equal.

Referring to FIG. 3, in the present embodiment, the branch angle 2θ of the Y branch is 2.5 °, the length from the end face to the branch is 30 μm, and the tapered waveguide 31 has a high reflection film side. To reach the end face of. For the coupling between the Y-branch waveguide and the straight waveguide portion 34, the radius of curvature of the curved waveguide 32 was set such that the interval 35 between the exit surfaces on the branch side of the Y-branch was 100 μm.

The width of the semiconductor laser device 100 is 300 μm.
m, and the length in the resonator direction was 650 μm.

The manufacturing process will be described with reference to FIGS. 1 and 2 again. Next, in order to obtain a current block structure, an oxide film is formed on the above-mentioned stripe by a self-alignment process, and a p-type InP The block layer 15 and the n-type InP current block layer 16 are grown and laminated on a portion excluding the upper part of the mesa stripe 23.

After removing the oxide film, the entire surface is covered with p-type I
An nP buried layer 17 and a p-type InGaAsP ohmic contact layer 18 are stacked to form a selectively grown buried structure.

Thereafter, a metal electrode 19 is formed on the p-type ohmic contact layer 18 on which the metal electrode 20 is formed on the n-type InP substrate 11.

Further, a high-reflection film 22 is formed on the end surface of the Y-branch waveguide before branching on the end surface formed by the cleavage method. The high reflection film 22 is made of SiO ₂ / amorphous Si / SiO ₂ / amorphous Si / SiO ₂
By using the phase structure, a reflectance of 90% or more can be obtained.

The other end face is entirely made of SiN
After applying a λ / 4 film made of (silicon nitride), using a mask as shown in FIG.
Amorphous Si / SiN / Amorphous Si / SiN
To form an AR film of the low reflection film 21 having a reflectance of 4% or less on one side of the end face (left side of the end face in front of FIG. 1).
Then, the other side has a five-layer structure of SiN / amorphous Si / SiN / amorphous Si / SiN, and the HR film of the high reflection film 22 having a reflectivity of 90% is formed (right side of the front end face in FIG. 1).

Next, the operation of this embodiment will be described with reference to FIG. The carrier supplied from the electrode 19 is injected into the active layer 13 through the ohmic contact layer 18, the p-type buried layer 17, and the p-type cladding layer 14 to form an active medium. The laser beam generated in the active medium is applied to a high reflection film 22 provided on one end face of the semiconductor element 100.
, Most of which is fed back into the active medium, and the Y-branch waveguide section causes the other end face to have a low reflection film side 2.
1 and the high reflection film side 22. Most of the light that has entered the high reflection film 22 on the other end face returns to the active medium again and is amplified again.

As described above, the amplification is repeated while the light reciprocates in the waveguide having the gain constituted by the Y-branch waveguide, the curved waveguide, and the linear waveguide. Part of the amplified light is emitted to the outside from the low reflection film 21 side.

It should be noted that, as in the prior art described with reference to FIG. 8, when the reflectance on the branched side is only AR, when the reflectance Rf on the AR side is small, The oscillation threshold current increases because the gain required for laser oscillation increases, and oscillation does not occur. However, in the present invention, since the HR film is provided at one end of the waveguide after branching, the reflectance of AR is increased. Even when Rf is 0.1% or less, it can be seen that the oscillation threshold value is small and oscillation occurs because the reflectance HR on the HR side is high.

When the semiconductor laser device of the first embodiment of the present invention having such a structure was experimentally evaluated, it was found that, at room temperature CW and large current injection, an element having a resonator length of 1200 μm in a linear waveguide was used. In comparison, 1 at 500 mA
The output was almost the same as 50 mW. In addition, due to the miniaturization, the stress at the time of assembling has been reduced by half, and the yield has been improved about twice.

Embodiment 2 Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a perspective view of the semiconductor laser device of the second embodiment. FIG. 6 is a top view of a plane cut along a plane A defined by an arrow in FIG.
5 and 6, the same elements as those in FIGS. 1 and 2 are denoted by the same reference numerals.

As shown in FIG. 5, in the second embodiment of the present invention, by forming the diffraction grating 60 on one of the waveguides having the gain after branching, the reflection end face after branching becomes A
Even in the case of R, the light is fed back to the waveguide having the gain again, so that there is an advantage (advantage) that the end face reflection film after branching may be only the AR film 21.

Further, since the wavelength is selected at the diffraction grating 60, there is an advantage that a spectrum having good monochromaticity can be obtained.

The manufacturing method is as follows: (001) n-type In
On the P substrate 11, a diffraction grating is formed only on one of the branched portions.

Next, in order to form a curved waveguide portion, a branch waveguide portion, and a tapered waveguide portion, a growth suppressing portion is patterned with an oxide film using a mask.

Next, the n-type InGaAsP guide layer 25 is formed by selective growth using metal organic vapor deposition (MOVPE).
An active layer 13 comprising a multiple quantum well (MQW), and p
By laminating the type InP cladding layer 14, a Y-branch mesa stripe having a diffraction grating on one side is formed.

The multiple quantum well structure is composed of InGaAs having a composition wavelength of 1.55 μm at the time of lattice matching by MOVPE selective growth.
A layer having a thickness of 4.1 nm with a compressive strain of 1.0% introduced into sP is used as a well layer, and the number of well layers is four. The barrier is InG having a thickness of 10.0 nm and a composition wavelength of 1.20 μm.
aAsP.

The length of the Y-branch waveguide section is the same as that of the first embodiment. The width of the semiconductor laser device was 300 μm, and the length in the cavity direction was 450 μm.

Further, the current block structure and the electrode structure
The structure is the same as that of the embodiment. A high reflection film 22 is formed on the end face of the resonator before branching of the Y-branch waveguide. The high reflection film 22 is made of SiO ₂ / amorphous Si / S
By using a five-layer structure of iO ₂ / amorphous SiO ₂ / SiO _2, the reflectance is obtained more than 90%. On the other end surface, a λ / 4 film made entirely of SiN is formed to form an AR film of the low reflection film 21 of 4% or less.

The semiconductor laser device according to the second embodiment of the present invention having such a structure was evaluated experimentally. As a result, at room temperature CW, the lasing threshold was 20 mA and the slope efficiency was 0.2.
An optical output of 60 mW was obtained at a drive current of 5 W / A and about 270 mA. The spectrum at the time of 60 mA output is S
The spectrum was good in monochromaticity with an MSR of 30 dB or more. In addition, the yield of chips per wafer has increased about twice.

[0072]

As described above, according to the present invention, the following effects can be obtained.

(1) The first effect of the present invention is that the length of the active medium can be longer than the length of the semiconductor laser device.

In the conventional semiconductor laser device, the length of the waveguide having a gain contributing to amplification is the same as the length of the resonator of the semiconductor laser device. However, according to the present invention, the length of the resonator of the semiconductor laser device is reduced. A waveguide length having about twice the gain can be obtained, and the semiconductor laser device can be downsized.

As a result, according to the present invention, stress due to heat can be reduced during assembly, and element deterioration and chip breakage due to this stress can be suppressed.

The reason is that, in the present invention, the contact area between the chip and the heat sink can be reduced. Therefore, according to the present invention, thermal stress can be reduced even when there is a slight difference in linear thermal expansion coefficient between materials.

(2) A second effect of the present invention is that productivity can be improved and a low-cost semiconductor laser can be provided.

The reason is that, in the present invention, the chip size (chip area) is reduced, so that the volume of one chip is reduced and the chip yield per wafer is increased.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a semiconductor laser device according to a first embodiment of the present invention.

FIG. 2 is a top view of a plane cut along a plane A in FIG. 1;

FIG. 3 is an enlarged plan view of a region 50 of FIG. 2;

FIG. 4 is a view for explaining the first embodiment of the present invention, showing a mask for realizing both an AR film and an HR film on one end face.

FIG. 5 is a perspective view showing a configuration of a semiconductor laser device according to a second embodiment of the present invention.

FIG. 6 is a top view of a plane cut along plane A in FIG. 5;

FIG. 7 is a perspective view showing an example of the configuration of a conventional semiconductor laser device.

FIG. 8 is a perspective view showing another configuration of a conventional semiconductor laser device.

[Explanation of symbols]

 Reference Signs List 11 n-type InP substrate 12 n-type InP cladding layer 13 active layer having a multiple quantum well structure 14 p-type InP cladding layer 15 p-type InP current blocking layer 16 n-type InP current blocking layer 17 p-type InP buried layer 18 p-type ohmic Contact layer 19 p-type ohmic electrode 20 n-type electrode 21 high reflection film (HR film) 22 low reflection film (AR film) 23 mesa stripe 24 waveguide having gain 25 n-type InGaAsP guide layer 31 tapered waveguide portion 32 branch conduction Waveguide part 33 Curved waveguide part 34 Straight waveguide part 35 Distance between straight waveguides

Claims (3)

(57) [Claims] 1. A high-power semiconductor laser device oscillating by current injection, wherein a waveguide having a gain is constituted by at least one Y-branch waveguide, two curved waveguides, and two linear waveguides, A first high reflection film is provided on the end surface of the Y-branch waveguide before branching.
Provided, made of a dielectric material monolayer film on the other end surface low reflection
A first region in which a film is formed, and a first region formed of a dielectric multilayer film.
A second region on which two highly reflective films are formed , wherein the first region is in contact with a linear waveguide for emitting light.
In addition, a straight waveguide that reflects light is in contact with the second region.
And it has a semiconductor laser device, characterized in that. 2. The method according to claim 1, wherein the second high reflection film is provided on the low reflection film.
2. The semiconductor laser device according to claim 1, wherein a dielectric multilayer film is formed on the semiconductor laser device. 3. A waveguide having a gain, comprising at least one Y-branch waveguide, two curved waveguides, and two straight waveguides, wherein said end face is formed by a cleavage method.
A first high reflection film is provided on the end surface of the Y-branch waveguide before branching.
The other end face has a low-reflection film consisting of a dielectric single-layer film.
A first region in which is formed, and a dielectric on the low reflection film.
A second high reflection film formed by forming a multilayer film;
A straight line that emits light in the first region.
The waveguide is in contact with the second region, and the second region has light reflection.
In the manufacturing method of the semiconductor laser device where the straight waveguide is in contact
A low-reflection film made of a dielectric single-layer film is provided on the light-emitting-side end face.
Forming and masking the first region and forming a dielectric in the second region.
The method of manufacturing a semiconductor laser device which comprises forming a body multilayer film.