JPH04121770U - Waveguide type semiconductor laser module - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a waveguide semiconductor laser module that has a simple structure, can be integrated in a small size, provides stable isolation, and has good light propagation efficiency. [Structure] Equipped with an optical waveguide 31 branched multiple times in a Y-shape from the output side toward the input side, semiconductor lasers 11, 12,
13 and 14 were installed. The returned light is attenuated by 1/2 each time it passes through the Y branch. Therefore, the semiconductor laser 1
The return light returning to 1, 12, 13, and 14 is greatly attenuated,
It has little effect on its properties.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention relates to a waveguide semiconductor laser module with optical isolator function. It is something to do.

0002

[Prior art]

Conventionally, semiconductor lasers have been used as light sources for optical communications; When the returning light enters the semiconductor laser, it causes interference resonance inside the semiconductor laser and generates noise. , the S/N ratio of the signal deteriorates. For this reason, an optical isolator is installed just before the light source. , the return light returning to the light source is removed.

0003 This type of optical isolator usually has two parts on both sides of a bulk Faraday rotator. Bulk polarizers are used which are rotated by 45 degrees with respect to each other. death However, it is difficult to miniaturize and integrate this type of optical isolator.

0004 Figure 4 shows a waveguide type optical isolator that eliminates the above drawbacks and achieves miniaturization and integration. An oblique view showing a semiconductor laser module 80 having a structure in which a laser diode and a semiconductor laser are integrated. This is a perspective view.

[0005] As shown in the figure, this semiconductor laser module 80 is a G.I. G. G. Board 83 A thin film waveguide 84 made of YIG is deposited on the thin film waveguide 84, and a thin film of A is deposited on the thin film waveguide 84. An Al vapor deposited film 85a, thin plate magnets 86a and 87a, and an Al vapor deposited film 88a are provided. It is constructed by attaching a semiconductor laser 81 to the side surface of the thin film waveguide 84. ing. Note that the two thin plate magnets 86a and 87a have different magnetic field application directions, The magnetic field application direction of the thin plate magnet 86a is horizontal, and the magnetic field application direction of the thin plate magnet 87a is vertical. With the above configuration, the thin film conductor provided with the Al vapor deposited film 85a can be formed. The part of the wave path 84 becomes a polarizer 85, and a thin plate magnet 86a and a thin plate magnet 87a are installed. The thin film waveguide 84 has a Faraday rotating part 86 and a cotton mouton part, respectively. The part of the thin film waveguide 84 that becomes the rotating part 87 and is provided with the Al vapor deposited film 88a is the analyzer 8. It becomes 8.

[0006] Then, the light emitted from the semiconductor laser 81 passes through the thin film waveguide 84 and becomes an arrow. The light is emitted in the direction shown by mark D. On the other hand, the returning light incident in the direction of arrow E is Photon 88, cotton mouton rotating section 87, Faraday rotating section 86, polarizer 85 Since it is removed during passing, it does not enter the semiconductor laser 81. In this case Utilizes both the Laday effect (non-reciprocal) and the Cotton Mouton effect (reciprocal) .

[0007]

[Problem that the idea aims to solve]

However, even in the semiconductor laser module 80 having the above structure, the following There was a problem.

[0008] Various functions such as Faraday rotating part 86 and cotton mouton rotating part 87 are required. Since the structure is complex, manufacturing costs are high.

[0009] Since a garnet-based Faraday rotator is used, the rotation angle is wavelength dependent. , It is temperature dependent and stable isolation cannot be obtained.

0010 The thin film waveguide 84 made of YIG has poor light transmission efficiency, so the light propagation efficiency is low. It gets worse. In addition, coupling optics are required to couple fibers with slab waveguides. It is necessary to add more systems.

[0011] The present invention was developed in view of the above points, and has a simple structure and is easy to integrate. A waveguide semi-conductor that provides stable isolation and good light propagation efficiency. An object of the present invention is to provide a conductor laser module.

0012

[Means to solve the problem] In order to solve the above problems, the present invention has a Y-shaped structure from the output side to the input side. It is equipped with an optical waveguide 31 branched multiple times, and the inner part of the optical waveguide end face on the input side is Attach semiconductor lasers 11, 12, 13, 14 to any of multiple locations to form a waveguide. A type semiconductor laser module 1 was constructed.

[0013]

[Effect]

The light emitted from the semiconductor lasers 11, 12, 13, and 14 enters the optical waveguide 31. The light enters the end face on the power side and is guided with almost no attenuation at multiple Y-branches. The light is emitted from the end face of the waveguide 31 on the emission side. On the other hand, among the emitted light, end face reflection, scattering, etc. The return light that returns to the output side end face is reduced by 1/2 every time it passes through the Y branch. It is attenuated by one. Therefore, the return light that returns to the semiconductor lasers 11, 12, 13, and 14 is is attenuated and has little effect on its characteristics.

[0014]

【Example】

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings. FIG. 1 is a diagram showing one embodiment of a waveguide type semiconductor laser module according to the present invention. Yes, the same figure (a) is a plan view, the same figure (b) is a front view, the same figure (c) is a left side view, the same figure (d) is an enlarged view of the vicinity of the semiconductor laser 11 shown in (b) of the same figure. It is shown in the same figure. The waveguide type semiconductor laser module 1 includes an optical waveguide provided with an optical waveguide 31. Four semiconductor lasers 11, 12, 13, and 14 are fixed to the left side of the substrate 33. has been completed. Each component will be explained below.

The optical waveguide substrate 33 is made of Si, and a buffer layer 35 containing SiO ₂ or a refractive index controlling additive is formed on its entire upper surface. An optical waveguide (core) 31 is provided on a predetermined portion of the upper surface of the buffer layer 35, and a cladding layer 37 is further formed over the entire upper surface of the buffer layer 35 so as to cover the optical waveguide 31. Here, the optical waveguide 31 is made of a high refractive index material such as SiO ₂ glass containing at least one type of high refractive index control additive such as Ti, Ge, P, B, Al, Na, etc., and also has a cladding layer. 37 is made of a low refractive index material such as SiO ₂ containing a refractive index controlling additive.

[0016] Here, the optical waveguide 31 has one output port 39 and four input ports 41, 42. , 43, 44 and two return light ports 45, 46, and the output port 39 is an input port. Input ports 41, 42, 4 are branched four times in a Y-shape toward the power side. 3, 44 and return light ports 45, 46. That is, output port 39 is branched by the first Y branch part 50-1, and each branched optical waveguide is again branched by the Y branch part 50-1. The optical waveguides are branched by the branching parts 50-2 and 50-3, and one of the branched optical waveguides is The optical waveguide is branched again by the Y branch portions 50-4 and 50-5, and further the part of the branched optical waveguide is Each one is branched again by Y branch parts 50-6 and 7, and input ports 41 and 4 It has reached 2,43,44. In addition, the Y branch portions 50-2, 3, 4, and 5 branch out. The other optical waveguide is assembled into two return light ports 45 and 46, and its tip is exposed on the left side surface of the optical waveguide substrate 33. Note that the cross-sectional shape of this optical waveguide 31 The shape is rectangular.

[0017] Here, each Y branch part 50 has a wide width, which is a characteristic of a Y branch type star coupler. It has band characteristics. Further, the branching angle θ of each Y branch 50 is It is preferable that the angle is within 3 degrees so that scattering loss and absorption loss in the portion 50 are small.

[0018] On the other hand, the four semiconductor lasers 11, 12, 13, and 14 each have four input ports. A support that also serves as a heat sink is provided at a position facing the It is fixed on a holder 15. These semiconductor lasers 11, 12, 13, 14 are Those with the same wavelength may be used, or those with different wavelengths may be used. Furthermore, each If laser beams with different wavelengths are used, each laser beam will not be coherent. Can be configured as multiple laser modules.

[0019] Next, to explain the operation of this waveguide type semiconductor laser module 1, for example, For example, the light emitted from the semiconductor laser 11 and incident on the input port 41 is divided into four Y components. The wave is guided with almost no attenuation at the branch portions 50-6, 4, and 2, and the wave is transmitted to the output port 39. reach and emit. For example, connect an optical fiber to the end face of this output port 39. For example, the laser light propagates within an optical fiber.

[0020] On the other hand, among the emitted light, the return that returns to the output port 39 due to end face reflection, scattering, etc. The emitted light is divided equally into 1/2 at the first Y branch section 50-1, and each The signal proceeds to Y branch portions 50-2 and 50-3, where it is equally divided into 1/2. and input port 41, 42, 43, and 44 are further provided with Y branch portions 50-4, 5, 6, and 7, respectively. Only the light equally distributed to 1/2 enters twice. Therefore, which semiconductor Only the return light attenuated to 1/16 returns to the lasers 11, 12, 13, and 14; The characteristics of the conductor lasers 11, 12, 13, and 14 are hardly affected. Further return The returned light collected in the optical ports 45 and 46 is emitted to the outside.

[0021] Here, if we ignore the end face reflection and the loss in the waveguide, the attenuation of the returned light is Pt (dB) is expressed by the following formula. n Pt=10・Log(1/2) However, n: the number of Y branch parts 50 to pass through

[0022] Here, if 10 stages of Y branch sections 50 are provided, the return light will reach the Y branch section 50 10 times. , the attenuation amount Pt is approximately -30.1 dB.

[0023] FIG. 2 shows a waveguide type semiconductor laser module 1' according to another embodiment of the present invention. FIG. As shown in the figure, it is branched at Y branch parts 50-2, 3, 4, and 5. The optical waveguide 31 that does not return to the semiconductor lasers 11, 12, 13, and 14 is cut in the middle. You may. Further, a light absorbing member 60 may be attached in front of the cut surface.

[0024] One embodiment of the waveguide semiconductor laser module according to the present invention has been described in detail above. However, the present invention can be modified in various ways as described below.

[0025] [1] In the above embodiment, the cross-sectional shape of the optical waveguide 31 is rectangular. The surface shape may be any other shape (for example, semicircular).

[0026] [2] FIG. 3 is a schematic enlarged view of a main part showing an optical waveguide 31 having another structure. Shown in the same figure As shown in FIG. The optical waveguide 31 may be sequentially branched from the inclined optical waveguide 31.

[0027] [3] In the above embodiment, four semiconductor lasers were attached to the input side, but The present invention is not limited to this, and the number can be changed as necessary.

[0028] [4] In Fig. 1, a light receiving photodetector is installed at the light emitting part of ports 45 and 46. Once installed, it can also be used as a light receiving section for two-way communication. In this case, for two-way communication Can be used as a module.

[0029] [5] FIG. 5 is a schematic enlarged view of the main part showing the shape of the Y branch part of another structure. In the same figure As shown, the shape of the Y branch narrows the width of the optical waveguide through which the incident light enters, and reduces the width of the returning light. The shape of the Y-branch may be asymmetrical, such as by widening the width of the optical waveguide through which the . With this configuration, most of the returned light will be guided toward the wide optical waveguide, and the incident light will be directed toward the wide optical waveguide. It will be difficult to return to.

[0030]

[Effect of the idea]

As explained in detail above, the waveguide semiconductor laser module according to the present invention According to , it has the following excellent effects.

[0031] A semiconductor laser model that has an optical isolator function using only a semiconductor laser and an optical waveguide. Since the module can be configured, the number of parts can be reduced, and it can also be made smaller and more integrated. I can figure it out.

[0032] Since the structure is simple, mass production is possible and costs can be reduced.

[0033] There is no wavelength dependence or temperature dependence, and stable isolation can be obtained.

[0034] No magnets are required, making it possible to achieve smaller size and lower cost.

[0035] By installing semiconductor lasers that emit laser beams of different wavelengths, Light sources of different wavelengths can be easily combined. Also used as a two-way communication module can.

[0036] The required isolation can be easily set by the number of Y branches.

[0037] Laser light emitted from a semiconductor laser propagates directly within the optical waveguide. , good light propagation efficiency.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of a waveguide type semiconductor laser module according to the present invention, in which FIG. 1(a) is a plan view, FIG. 1(b) is a front view, and FIG. 1(c) is a left side view. Figure, same figure (d)
2 is an enlarged view of the vicinity of the semiconductor laser 11 shown in FIG. 3(b).

FIG. 2 is a plan view showing a waveguide type semiconductor laser module 1' according to another embodiment of the present invention.

FIG. 3 is a schematic enlarged view of a main part showing an optical waveguide 31 having another structure.

FIG. 4 is a perspective view showing a conventional semiconductor laser module 80.

FIG. 5 is a schematic enlarged view of the main part showing the shape of the Y branch part of another structure.

[Explanation of symbols]

1 Waveguide type semiconductor laser module 11, 12, 13, 14 Semiconductor laser 31 Optical waveguide

Continuing from the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location // H01L 33/00 M 8934-4M

Claims (1)

[Scope of utility model registration request] Claim 1: An optical waveguide that is branched multiple times in a Y-shape from an output side toward an input side, and a semiconductor laser or a semiconductor laser is installed at any plurality of the plurality of end faces of the optical waveguide on the input side. A waveguide type semiconductor laser module characterized by having a photodetector attached thereto.