JPH09331102A - Wavelength multiplexing light source whose laser outgoing end surface is inclined - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small wavelength multiplexing light source of high output whose condensing/integrating design is easy by devising a light-emitting end structure of a semiconductor laser array. SOLUTION: A wavelength multiplexing light source comprises a semiconductor laser array 11 and a channel wave guiding type confluence device 12. The light-emitting end surface of each laser 101-108 of the semiconductor laser array 11 is formed in a plane perpendicular to a substrate of the wavelength multiplexing light source, and further, relating to at least one of the semiconductor laser, it is inclined against its resonator axis. Beams of light from the respective lasers 101-108 of the semiconductor laser array 11 are emitted at specified angles, and made to join each other with the channel wave guiding type confluent device 12 which is formed of a material different from the semiconductor laser array 11, and then emitted from an output waveguide part 13.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an optical communication system,
In particular, the present invention relates to a wavelength division light source used in a wavelength division multiplexing communication system, a communication system using the same, and the like.

[0002]

2. Description of the Related Art A wavelength division multiplexing communication system (hereinafter referred to as WD
M system) is used in various fields because it can transmit a large amount of information at high speed by utilizing the wide band property of the light wavelength. A tunable laser is a key device that supports this WDM system. In particular, a wavelength multiplexing light source in which a plurality of wavelength tunable lasers are integrated is effective for improving the wavelength multiplexing and system flexibility. That is, it is a device capable of simultaneously controlling and transmitting light of a plurality of wavelengths.

In order to transmit the transmission light from the wavelength division multiplex light source to the optical fiber, there are roughly two methods. One is a form in which an array of optical fibers and an array of light sources are combined, and the merging of the fiber arrays is performed by a fiber star coupler. The other is to combine the lights emitted from the light source array and guide them to one optical fiber. The former method has an advantage that the coupling loss can be relatively low because the light is merged by the fiber star coupler, but there is a problem that the optical arrangement of the light source array and the optical fiber array is complicated and the size is increased. In the latter method, the light emitted from the light source array is collected at the time of coupling with the optical fiber, so that it is possible to avoid the complexity of the arrangement and the enlargement of the device. Therefore, for example, as seen in US Pat. No. 5,394,489, a waveguide type star coupler is formed on a substrate on which a distributed feedback semiconductor laser array is formed, and laser emission lights are combined. A wavelength division multiplex light source that outputs light from a single waveguide has been proposed.

[0004]

However, the wavelength multiplex light sources described in the above-mentioned US Pat. There was a problem that the length became long. Further, the utilization efficiency of the laser emission light including the excitation to the optical fiber is not high. Further, the reflected return light from the entrance end face of the merger causes the deterioration of the laser characteristics.

In view of these problems, the object of the present invention will be described below in correspondence with each claim.

The first to third objects of the present invention are to provide a wavelength multiplexing light source which is small in size, high in output, and easy in focusing / integrating design by devising a semiconductor laser array emitting end structure.

A fourth and fifth object of the present invention is to provide a wavelength division multiplex light source that is compact and capable of collecting light efficiently by devising a converging waveguide.

A sixth object of the present invention is to provide a wavelength multiplexing light source whose mode is stable during modulation by devising a semiconductor laser array.

A seventh object of the present invention is to provide a wavelength division multiplex light source whose oscillation line width is small during modulation by devising a semiconductor laser array.

An eighth object of the present invention is to provide a wavelength multiplexing light source having a large degree of freedom in wavelength multiplexing arrangement by devising a semiconductor laser array.

A ninth object of the present invention is to provide a wavelength division multiplex light source having a wide wavelength division range by devising a semiconductor laser array.

A tenth object of the present invention is to provide an opto-electric converter for optical transmission by polarization modulation.

An eleventh object of the present invention is to construct a system such as a wavelength division multiplexing local area network utilizing optical transmission by polarization modulation.

[0014]

The structure and operation of the wavelength multiplex light source of the present invention for achieving the above first to fifth objects are as follows. That is, in a wavelength division light source composed of a semiconductor laser array and a channel waveguide type multiplexer,
The emitting end faces of the respective lasers of the semiconductor laser array are formed in a plane perpendicular to the substrate of the wavelength division multiplex light source, and at least one semiconductor laser is inclined with respect to its resonator axis. The light from each laser of the semiconductor laser array is emitted at a predetermined angle, and the light is combined and emitted by a channel waveguide type combiner made of a material different from that of the semiconductor laser array (claim (Corresponding to item 1). The emission end face of the semiconductor laser forming the semiconductor laser array has a gradually increasing inclination angle from the center of the array toward the peripheral part of the array (corresponding to claim 2), or the emission end face of the semiconductor laser forming the semiconductor laser array. Is set to have a Brewster's angle with respect to the guided light of TE mode (corresponding to claim 3), and the channel waveguide type multiplexer has a linear branch waveguide extending from each laser and the branch. It is composed of a rake coupler having a merging portion where the waveguides are gathered (corresponding to claim 4), and the channel waveguide merging device is a straight trunk waveguide and a straight line that joins the trunk waveguide at each position. It may be composed of a branch type coupler having a branching waveguide (corresponding to claim 5).

Specifically, the emission ends of the individual lasers forming the semiconductor laser array are connected to the converging waveguide, and the emission end face is tilted with respect to the laser cavity axis, whereby the laser emission light is emitted. It is emitted obliquely, merges into one output waveguide, and is emitted. FIG. 2 schematically shows this principle. Since the emission end face 22 of the semiconductor laser 21 is obliquely cut, the emitted light is refracted and the light travels in parallel to the waveguide 23 provided at an angle. At this time, by controlling the inclination angle θ ₁ of the laser emission end face 22 for each position of each laser of the laser array, the emission angle θ _{2 of} light can be changed, and the light can be condensed efficiently at the confluencer. it can. The tilt angle θ _{2 with} respect to the laser resonator axis is expressed as follows, as is well known as Snell's law. θ ₂ = −θ ₁ + sin ⁻¹ (n ₁ / n ₂ sin θ ₁ ) (1) where n ₁ and n ₂ respectively represent the equivalent refractive index of the semiconductor laser 21 and the junction waveguide 23.

Therefore, as shown in FIG. 1, the inclination angle is gradually changed for each of the lasers 101 to 108 of the semiconductor laser array 11, and the emitted light is the output waveguide portion 13 of the channel waveguide type junction device 12. I am trying to converge to. As a result of the above configuration, the semiconductor laser array 11
Among them, the light emitted from the central portion 14 of the array is almost straight, and the light emitted from the peripheral portion 15 of the array is bent so that it is condensed by the Fresnel lens.
Then, all the light goes toward the output waveguide portion 13 through a rake-shaped or branched optical coupling as shown in FIG. In the present invention, the waveguide forming the junction has a different equivalent refractive index than the waveguide forming the semiconductor laser so that refraction occurs at the laser emission end face. In the configuration of FIG. 1, the outgoing light from each laser travels symmetrically about the central portion, but the method of setting the outgoing end face of each semiconductor laser is not limited to this.

The structure and operation of the wavelength multiplexing light source of the present invention for achieving the sixth to ninth objects are as follows. 6)
By constituting the semiconductor laser array with a distributed feedback type or distributed reflection type laser, it is possible to dynamically and stably oscillate (corresponding to claim 6). 7) The semiconductor laser array
By adopting a laser in which the polarization mode of the oscillated light is switched between the TE mode and the TM mode, an increase in the line width at the time of modulation can be suppressed (corresponding to claim 7). Since the laser whose emission end face is cut at the Brewster angle has polarization dependence, it also has the function of improving the polarization extinction ratio together with the polarizer provided at the output end of the combiner. 8) The oscillation wavelength of each laser of the semiconductor laser array is independently variably controlled, so that transmission of free wavelength channels becomes possible (corresponding to claim 8).
9) Since the semiconductor lasers forming the semiconductor laser array have different oscillation wavelengths from each other, wide-band wavelength division multiplexing communication can be performed (corresponding to claim 9).

The configuration and operation of the apparatus and system of the present invention for achieving the above tenth and eleventh objects are as follows. 10) Using the long multiplex light source as a transmitter and the wavelength tunable optical filter and the light receiving element as a receiver, these can be combined into a single optical-electrical conversion device used in a wavelength multiplex local area network or the like ( (Corresponding to claim 10). 9) Using the above photoelectric conversion device,
A wavelength division multiplexing optical transmission system can be constructed by performing polarization modulation of a transmitting device, converting polarization modulated light into intensity modulated light for transmission, and receiving light of a desired wavelength by a receiving device (claim 11). Correspondence).

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment A first embodiment according to the present invention will be described with reference to FIG. 1
Reference numeral 1 denotes a laser array of distributed feedback type lasers 101 to 108 of 8 arrays each having a two-electrode configuration. Reference numeral 12 denotes a channel waveguide type merger having a rake configuration. Also,
Reference numeral 13 is an output waveguide section. FIG. 3 shows a cross section in the waveguide direction of FIG.

The wavelength multiplexing light source of this embodiment will be described with reference to these two figures. The layer structure of the semiconductor laser array is n
A 0.5 μm thick n-InP buffer layer 303 in which a grating 302 having a period of 240 nm is formed on an InP substrate 301, and a 0.15 μm thick n-InGaAsP (bandgap wavelength λg = 1.17 μm) optical guide layer 30.
4, 0.08 μm thick i-InGaAsP (λg = 1.
51 μm) Active layer 305, 0.4 μm thick p-InGa
AsP (λg = 1.17 μm) light guide layer 306, 1.
8 μm thick p-InP clad layer 307, p-InGa
It has a form in which As contact layers 308 are laminated. In the laser resonator, a ridge having a waveguide width of 3 μm is formed,
Both sides in the lateral direction are filled with a high resistance InP layer.
The distance between the lasers 101 to 108 in the lateral direction is 250 μm, and the length in the cavity direction is 700 μm.

Next, the end surface of the semiconductor laser array 11 on the confluencer side is removed by etching up to the n-InP substrate 301 obliquely as viewed from above by a lithography method using a photomask. Polyimide PIX is used as the cladding 311 for the channel waveguide type junction 12 on the removed surface.
(Hitachi Chemical Co., Ltd.) was applied and baked, and then a polyimide UR5100FX (manufactured by Toray) was applied as the core 312. Then, the UR5100FX is exposed using a photomask.
After development, a pattern of a rake-shaped channel waveguide type merger 12 as shown in FIG. 1 was formed. Similarly, firing is performed, PIX is applied as the upper clad 313, and firing is performed to manufacture the channel waveguide junction 12. In the semiconductor laser region, up to the contact layer 308 in the electrode isolation region is removed to divide the resonator into two, and Au / Zn / Au which is a p-electrode.
A layer 309 is formed, an AuGe / Au layer 310 of an electrode is formed on the substrate side, and these are alloyed.

Lasers 101-of the semiconductor laser array 11
Reference numeral 108 controls the current injected into each of the two electrodes, so that the oscillation wavelength can be varied over 2 nm. FIG.
As shown in FIG. 5, the light emitted from each of the lasers 101 to 108 is refracted at the obliquely formed end face and propagates to the polyimide waveguide, and then is coupled to the output waveguide portion 13 through the merging portion 16. At that time, since the exit end surface is distributedly inclined,
The emitted lights of the lasers 101 to 108 are naturally condensed as shown in FIG. The inclination angle θ ₁ of the emitting end face 22 of the semiconductor laser is 101, 10 is 20 degrees, 102, 10
7 is 16 degrees, 103, 106 is 10.5 degrees, 104, 1
05 is 4 degrees, and the length from the semiconductor laser array 11 to the confluence 16 is 1.6 mm. Output waveguide section 13
The length of 400 μm of the channel waveguide type junction 12
Has a length of about 2 mm. Since the waveguide does not need to be bent in the region near the laser emission end face, the element length is short, and
DFB does not return to the resonator because the end face is tilted
It also has the effect of stabilizing the oscillation. The condensed light is emitted through the output waveguide section 13. Therefore, according to this wavelength multiplexing light source, it is possible to simultaneously carry signals on eight wavelengths and transmit them onto the optical fiber.

Second Embodiment Next, an example in which the semiconductor laser array has a configuration capable of switching polarization will be described. By controlling the injection current to the two electrodes, the polarization mode of oscillation can be switched. Then, the output is passed through a polarization selecting element such as a polarizer to obtain amplitude-modulated light. Compared with the normal direct amplitude modulation method, there is a feature that modulation can be performed with a small amplitude current. Further, since the amount of carrier fluctuation in the laser is small, it is possible to suppress the line width expansion during modulation. Therefore, it is necessary to make the TE and TM mode threshold gains of light near the oscillation wavelength approximately the same.

In a commonly known quantum well semiconductor laser, the cavity gain is large for the TE mode and TM
Although it becomes smaller than the mode, in the present embodiment, the resonator gain that the TM mode receives in the distributed feedback laser resonator is made equal to the resonator gain that the TE mode receives in the distributed feedback laser resonator, and in the TM mode, Makes it easy to oscillate. One is that the Bragg wavelength is set near the gain peak of the TM mode on the shorter wavelength side than the gain peak of the TE mode. Furthermore, the point is that a strained quantum well is introduced into the active layer.

In the above structure, the equivalent refractive index of the resonator is changed non-uniformly by injecting non-uniform current into the plurality of electrodes, and either the TE mode or the TM mode, whichever has a lower threshold gain, is biased. It oscillates in wave mode.

The configuration and operation of this embodiment will be described with reference to FIG. On the n-InP substrate 401, a 0.15 μm thick n-InGaAsP (λg = 1.17 μm) optical guide layer 402 and an active layer 403 are laminated. The strained quantum well serving as the active layer 403 is a 5-quantum well in which the well layer is i-In _0.53 Ga _0.47 As (thickness 6 nm) and the barrier layer is i-In _0.28 Ga _0.72 As (thickness 10 nm). . Furthermore,
0.1 μm thick p-InGaAsP (λg = 1.17 μm
m) The light guide layer 404 is formed, and the grating 405 having a period of 240 nm is formed on the light guide layer 404. On top of this, p-InP clad layer 406, p-InGaA
The s contact layer 407 is laminated.

In the lateral direction, a high mesa having a waveguide width of 3 μm is formed, and both sides are filled with a high resistance InP layer. The grating 405 is a quarter wavelength shift 40.
8 is formed at the center of the one-sided electrode. Subsequently, the contact layer 407 is removed to provide an electrode separation region, an Au / Cr layer 409 that is a p-electrode is formed on the upper portion, and an AuGe / Au layer 410 that is an electrode is formed on the substrate side. It has become. The length of each p-electrode area is 300μ
m, 300 μm. From this state, each p electrode 409
Polarization mode switching between TE ← → TM was realized by controlling the amount of current injection into.

Subsequently, the laser end face is formed on the InP substrate 311.
By etching and removing, a polyimide waveguide coupler was formed in the same manner as in the first embodiment. FIG. 5 is a view of the wavelength multiplexing light source according to the present embodiment as viewed from above. All the laser emitting end faces 53 of the semiconductor laser array 51 are etched to a Brewster angle of 24.5 degrees. Each waveguide of the polyimide waveguide coupler 52 goes toward the output waveguide section 54, and the coupling with the output waveguide section 54 is as shown in FIG.
The branches are merging in sequence so that they are attached to the trunk.

Of the light emitted from the semiconductor laser array 51, the light oscillated in the TE mode is transmitted to the re-polyimide waveguide coupler 52 having a high transmittance at an emission angle close to the Brewster angle, as shown in FIG. It shifts and is emitted from the output waveguide section 54. However, the emitted light switched to the TM mode has a high reflectance at the end face 53, and the light does not move to the simple polyimide waveguide coupler 52. Since this reflected light is reflected obliquely with respect to the cavity axis, there is no adverse effect on the laser. The TM mode light that has been transferred also has a polarizer 55 provided at the output end.
The light, which is blocked by and is polarization-modulated, is converted into amplitude modulation.

Third Embodiment An embodiment in which optical transmission is performed using the wavelength division multiplexing light source 60 according to the present invention will be described with reference to FIG. Reference numeral 61 denotes a semiconductor laser array in which the oscillation wavelength and the extinction ratio are stably controlled and the polarization is modulated according to the present invention. In this semiconductor laser array 61, the wavelength can be changed within a range of 2 nm with a wavelength interval of about 10 GHz (about 0.08 nm). Further, in polarization modulation, a dynamic wavelength variation called chirping which is a problem in a normal direct intensity modulation method is 2 GHz (about 0.0
Since it is very small (16 nm) or less, crosstalk is not given to an adjacent channel even if wavelength-multiplexed are arranged at 10 GHz intervals. Therefore, when this semiconductor laser array is used, wavelength multiplexing of 2 / 0.016, that is, 100 channels or more is possible. The light emitted from the semiconductor laser array 61 is excited into the optical fiber 63 through the channel waveguide combiner 62.

The wavelength multiplexing light source 60 and the wavelength demultiplexing receiver 6
An optical communication system composed of 4 and 4 will be described. The light emitted from the wavelength division multiplexing light source 60 is transmitted to the network through the fiber star coupler 69. The optical signal transmitted through the optical fiber 63 is subjected to selective demultiplexing of the light of a desired wavelength channel by the optical filter 65 in the wavelength demultiplexing receiver 64, and signal detection by the photodetector 66.
Here, the optical filter 65 having the same structure as the distributed feedback laser is used with the current biased below the threshold value. By changing the current ratio of the two electrodes of the optical filter 65, the transmission gain is kept constant at 20 dB and the transmission wavelength is set to 2 n.
You can change m. Also, this filter 65 10
The transmission width of dB down is 0.03 nm and is 0.08 n
It has sufficient characteristics for wavelength multiplexing at an interval of m.
An optical filter having a similar wavelength transmission width, for example, a Mach-Zehnder type or Fabry-Perot type wavelength filter or a demultiplexer using a grating may be used.

As a network of an optical communication system, a star type is shown in FIG. 6, and a large number of terminals and centers can be installed by connecting optical nodes to the network. The network may be a ring type, a bus type, or a combination of a plurality of types.

Fourth Embodiment FIG. 7 shows an example in which a distributed reflection type semiconductor laser is used as a laser array.
It will be explained by. The layer structure of the semiconductor laser array is n
-On the InP substrate 701, 0.2 μm thick n-In _0.79
Ga _0.21 As _0.45 P _0.55 Lower optical guide layer 702, i-In _0.59 Ga _0.41 As _{0.87 with a} thickness of 0.05 μm to be an active layer
After growing P _0.13 703, the active layer 703 is partially removed,
A 0.2 μm thick p-In _0.79 Ga _0.21 As _0.45 P _0.55 upper optical guide layer 704 is formed. Then, a distributed reflection grating 705 having a period of 237 nm is formed on the upper light guide layer 704 in the region where the active layer is removed. Furthermore, a p-InP clad layer 706 and a p-In _0.59 Ga layer are formed thereon.
_{A 0.41} As _0.9 P _0.1 contact layer 707 is laminated.

In the lateral direction, a ridge having a width of 3 μm in the active layer 703 is formed and embedded with a SiN _x layer. The formation of the electrodes 708 and 709 is the same as in the first embodiment. As described above, the semiconductor laser array 71 including the distributed Bragg reflector laser was manufactured.

Subsequently, the emission end face on the side of the channel waveguide type junction 72 was obliquely removed by etching to form a rake type junction 72 composed of polyimide waveguides 311, 312, 313 having a core thickness of 3 μm.

In this embodiment, since the distributed Bragg reflector type laser is applied, the wavelength tunable range is about 4 nm, which is twice as wide as the distributed feedback type. Further, since the channel waveguide combiner 72 has no polarization dependency, the light emitted from the laser array 71 is polarization discriminated by a polarizing plate externally attached to the output waveguide to obtain amplitude-modulated signal light. To be

[0037] An example of the fifth embodiment the semiconductor laser wavelength multiplexing light source was different from each other each oscillation wavelength of the array in FIG. Distributed feedback laser 801
˜808, since the oscillation wavelength is almost proportional to the grating period, the central wavelength of each distributed feedback laser is changed to 2n by changing the period in the vicinity of 240 nm by 0.3 nm.
I changed it by m. Since the wavelength spacing of wavelength division multiplexing is set wide, it is suitable for a system that uses the transmission side as a fixed wavelength. Since the wavelength spacing is relatively wide, around 2 nm,
In addition to the optical filter shown in the third embodiment, the optical receiver may be composed of a demultiplexer composed of a grating or an interference multilayer film.

In each of the above-described embodiments, the ridge formation and the burying with the high resistance layer have been described as examples, but the current constriction and the light confinement utilizing the reverse bias of the pn junction may be used. Is also good. Also, the optical confinement structure in the plane of the waveguide is not limited to the buried hetero structure, and any structure that confine light in the lateral direction may be used.

[0039]

As described above, the respective effects of the present invention (corresponding to claims 1 to 10) are as follows.

According to 1) -5), in the wavelength multiplexing light source, the emitting end face of at least one laser is inclined with respect to the optical axis of the semiconductor laser in a plane perpendicular to the optical transmitter substrate. Optical coupling to the channel waveguide type merger is smooth, and the size is compact and the degree of freedom in condensing design (the arrangement of lasers can be freely designed by giving the angle of the emitting end face) is large and the wavelength division is high. A wavelength division multiplex light source for multiplex transmission can be provided. Further, since the emitting end surface is inclined, reflected return light can be suppressed. According to 6), the semiconductor laser array in the above 1) -5) is configured by a distributed feedback laser or distributed reflection laser, which has an effect of enabling dynamically stable oscillation. According to 7), the semiconductor laser array is a laser in which the polarization mode of the oscillated light is switched between the TE mode and the TM mode, so that the line width at the time of modulation of the wavelength multiplex light source described in 1) to 6) above. It has the effect of suppressing the increase. According to 8), the oscillation wavelength of the semiconductor laser array is independently variably controlled, so that it is possible to provide the wavelength multiplex light source described in 1) to 7) above, which is capable of freely transmitting wavelength channels. According to 9), since the semiconductor lasers forming the semiconductor laser array have different oscillation wavelengths from each other, it is possible to provide the wavelength division multiplex light source described in 1) to 7) above, which is capable of broadband wavelength division multiplexing communication.

Further, according to 10), it is possible to provide an opto-electric conversion device for constructing a wavelength division multiplexing local area network or the like utilizing optical transmission by polarization modulation. According to 11), it is possible to construct a transmission system such as a wavelength division multiplexing local area network using optical transmission by polarization modulation.

[Brief description of drawings]

FIG. 1 is a plan view showing a light source for wavelength division multiplex transmission or the like according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation principle of the wavelength division multiplexing light source of the present invention.

FIG. 3 is a sectional view in the waveguide direction of the first embodiment of the present invention.

FIG. 4 is a sectional view in the waveguide direction of a second embodiment of the present invention.

FIG. 5 is a plan view of a second embodiment of the present invention.

FIG. 6 is a block diagram illustrating an optical communication system using a wavelength division multiplexing light source according to the present invention.

FIG. 7 is a sectional view in the waveguide direction of a fourth embodiment of the present invention.

FIG. 8 is a plan view of a fifth embodiment of the present invention.

[Explanation of symbols]

11, 51, 61, 71: semiconductor laser array 12, 52, 62, 72: channel waveguide type merger 13, 54: output waveguide portion 14: laser array central portion 15: laser array peripheral portion 16: merged portion 21, 101- 108, 801 to 808: Semiconductor lasers 22, 53: Laser emitting end face 23: Combiner waveguide 55: Polarizer 60: Wavelength multiple light source 63: Optical fiber 64: Wavelength demultiplexing receiver 65: Optical filter 66: Photodetector 69: Fiber star coupler 301, 401, 701: Substrate 302, 405, 705: Grating for laser 303: Buffer layer 304, 306, 402, 404, 702, 704: Optical guide layer 305, 403, 703: Active layer 307, 406, 706: Cladding layers 308, 407, 707: Contact layers 309, 31 , 409,410,708,709: electrodes 311,313: waveguide clad 312: a waveguide core 408,313: λ / 4 shift portion

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[Procedure amendment]

[Submission date] August 28, 1996

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

[Figure 5]

[Fig. 2]

[Figure 3]

FIG. 4

FIG. 6

FIG. 7

[Figure 8]

Claims (11)

[Claims] 1. A wavelength multiplex light source composed of a semiconductor laser array and a channel waveguide type converging device, wherein each laser emitting end face of the semiconductor laser array is formed in a plane perpendicular to a substrate of the wavelength multiplex light source. In addition, since at least one semiconductor laser is tilted with respect to its resonator axis, light from each laser of the semiconductor laser array is emitted at a predetermined angle and is formed of a material different from that of the semiconductor laser array. The channel waveguide type merger
A wavelength division light source characterized by being emitted. 2. The wavelength-division multiplex light source according to claim 1, wherein an emission end face of a semiconductor laser forming the semiconductor laser array has an inclination angle gradually increasing from an array central portion toward an array peripheral portion. 3. The wavelength multiplex according to claim 1, wherein the emission end face of the semiconductor lasers constituting the semiconductor laser array is set to have a Brewster angle with respect to the TE mode guided light. light source. 4. The channel waveguide type combiner comprises a rake coupler having a linear branch waveguide extending from each laser and a merge section where the branch waveguides are gathered. Item 5. The wavelength multiplexing light source according to item 1, 2 or 3. 5. The channel waveguide type combiner comprises a branch type coupler having a straight trunk waveguide and straight branch waveguides that join the trunk waveguide at respective points. The wavelength-multiplexed light source according to claim 1, 2 or 3. 6. The wavelength multiplexing light source according to claim 1, wherein the semiconductor laser array has a configuration in which distributed feedback or distributed reflection lasers are arranged in parallel. 7. The wavelength division multiplex light source according to claim 1, wherein each laser of the semiconductor laser array has a polarization mode of oscillation light switched between a TE mode and a TM mode. 8. The wavelength-division multiplex light source according to claim 1, wherein the semiconductor lasers constituting the semiconductor laser array are independently variably controlled in oscillation wavelength. 9. The wavelength division multiplex light source according to claim 1, wherein the semiconductor lasers forming the semiconductor laser array have different oscillation wavelengths from each other. 10. An optical device comprising the wavelength-multiplexed light source according to any one of claims 1 to 9 as a transmitter, and a wavelength-tunable optical filter and a light-receiving element as a receiver, which are combined into one. An electrical conversion device. 11. The optical-electrical converter according to claim 10, wherein polarization modulation of each laser of a semiconductor laser array of a wavelength multiplex light source is performed, polarization modulated light is converted into intensity modulated light, which is transmitted and received. A wavelength division multiplexing optical transmission system characterized in that a device receives light of a desired wavelength.