JP2001133664A - Semiconductor laser module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor laser module which hardly causes breakdown of a semiconductor laser element or an optical fiber and offers a high coupling efficiency. SOLUTION: A semiconductor laser element 1 is mounted on a heat sink 11 and is fixed on a carrier 7 by solder, and the carrier 7 is fixed to a cooling side substrate of an electronic cooler 10, which controls the temperature to stabilize the optical output and the wavelength of the semiconductor laser element 1 by solder, and the electronic cooler 10 is fixed to the inside bottom of a module package 4 by solder. A photodiode 8 which monitors the optical output of the semiconductor laser element 1 and a lens 3 which condenses emitted light of the semiconductor laser element 1 are mounted on the carrier 7, and an optical fiber 2, having a taper part 21, is so adjusted that it is coupled efficiently with light from the lens 3, and the optical fiber 2 is fixed above the carrier 7 by a fiber holder 22. A space between the module package 4 and the optical fiber 2 is filled with a solder having low-melting point or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser module, and more particularly, to a 980 nm band semiconductor laser module structure.

[0002]

2. Description of the Related Art A 980 nm band semiconductor laser device has an elliptical radiation pattern having a vertical radiation angle of 20 to 40 degrees and a horizontal radiation angle of 5 to 15 degrees, and a mode field diameter close to a perfect circle. Excess loss occurs in the optical coupling with the optical fiber.

As a means for solving this problem, there is a method in which a cylindrical lens is used to focus light only in the vertical direction to make the beam shape close to a circle. However, in this configuration, since the light is not condensed in the horizontal direction, it cannot solve the improvement of the coupling efficiency. As another means, there is a beam shaping lens and an elliptical fiber shape.
There is a problem that fiber processing is not easy.

As a configuration for improving these problems and improving the coupling efficiency, there is a means for processing the end face of the fiber into a tapered shape. According to this, processing of the fiber can be easily performed by means such as polishing. Also, since the semiconductor laser element and the fiber can be brought close to each other,
The non-concentration in the horizontal direction is negligible.

That is, in the above-described semiconductor laser module, as shown in FIG. 4, the semiconductor laser element 1 is mounted on a heat sink 11 and fixed on a carrier 7 by soldering.

[0006] The carrier 7 is an electronic cooler 1 for controlling the temperature in order to stabilize the light output and wavelength of the semiconductor laser device 1.
0 is fixed to the cooling side substrate by soldering. Electronic cooler 10
Are fixed to the inner bottom surface of the module package 4 by soldering.

A photodiode (PD: Photo) for monitoring the optical output of the semiconductor laser device 1 is provided on the carrier 7.
The optical fiber 2 is fixed on the carrier 7 via the fiber holder 22 so that the tapered portion 21 approaches the semiconductor laser device 1. The gap between the module package 4 and the optical fiber 2 is filled with a low melting point solder or the like for hermetic sealing.

This conventional optical system, as shown in FIG.
Semiconductor laser device 1 and optical fiber 2 having tapered portion 21
It is composed only of In FIG. 5, light emitted from a semiconductor laser element 1 is focused on an optical fiber 2,
The light output is taken out. At this time, the distance between the semiconductor laser device 1 and the optical fiber 2 at the optimum coupling position is L2.

[0009]

However, in the above-described configuration, the distance between the optical fiber and the semiconductor laser element at the time of optimal coupling is very short, several tens of μm. There is a high risk of damaging the semiconductor laser device.

Accordingly, an object of the present invention is to provide a semiconductor laser module which solves the above problems, makes it difficult for semiconductor laser elements and optical fibers to be damaged, and can obtain high coupling efficiency. is there.

[0011]

A semiconductor laser module according to the present invention is a semiconductor laser module including an optical fiber having a tapered end face and a semiconductor laser element optically coupled to the optical fiber. And a lens inserted between the semiconductor laser element and the optical fiber with a space between the semiconductor laser element and the optical fiber.

That is, the semiconductor laser module of the present invention uses a lens for the optical system and an optical fiber having a tapered lens surface on the end face, thereby preventing the semiconductor laser element and the optical fiber from being damaged. It is characterized in that coupling efficiency can be obtained.

Specifically, the semiconductor laser module of the present invention has a 980 nm band semiconductor laser device, an optical fiber having a tapered portion (lens portion) whose tip is processed into a tapered shape, and light emitted from the semiconductor laser device. And a lens arranged so that the image magnification is about 1.

Light emitted from the semiconductor laser device is condensed by a lens and optically coupled to an optical fiber. The distance between the optical fiber and the semiconductor laser element when there is no lens is about several tens of μm, but in the configuration with the lens, the distance between the semiconductor laser element and the lens and the lens It is possible to increase the distance between the fiber and the optical fiber.

With the above configuration, in a 980 nm band semiconductor laser module, a module having high coupling efficiency can be obtained without damaging the semiconductor laser element or the optical fiber during adjustment.

[0016]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a semiconductor laser module structure according to one embodiment of the present invention. In FIG. 1, a semiconductor laser device 1 is mounted on a heat sink 11 and fixed on a carrier 7 by soldering.

The carrier 7 is an electronic cooler 1 for controlling the temperature in order to stabilize the light output and wavelength of the semiconductor laser device 1.
0 is fixed to the cooling side substrate by soldering. Electronic cooler 10
Are fixed to the inner bottom surface of the module package 4 by soldering.

A photodiode (PD: Photo) for monitoring the optical output of the semiconductor laser device 1 is provided on the carrier 7.
(Diode) 8 and a lens 3 for condensing light emitted from the semiconductor laser device 1. The lens 3 has an image magnification of about 1, or is arranged so as to be 1. That is, the lens 3 is inserted with a space between the semiconductor laser element 1 and the optical fiber 2 so as to separate the semiconductor laser element 1 from the optical fiber 2.

The optical fiber 2 having the tapered portion 21 is adjusted so as to couple with light from the lens 3 with high efficiency, and is fixed on the carrier 7 via the fiber holder 22. The gap between the module package 4 and the optical fiber 2 is filled with low melting point solder or the like for hermetic sealing.

FIG. 2 is a view showing an optical system of a semiconductor laser module structure according to one embodiment of the present invention. In FIG. 2, light emitted from the semiconductor laser device 1 has a certain distance L1.
Is condensed through the lens 3 arranged while maintaining the distance L
Focus on 1

Since the lens 3 has an image magnification of about 1 or is disposed so as to be 1, the focal point is set at the lens 3.
Can be regarded as a light emitting point of the semiconductor laser element in the case where there is no light, and the light is focused on the optical fiber 2, so that an optical output can be taken out. At this time, the distance required between the semiconductor laser element 1 and the optical fiber 2 is L2, so the distance between the lens 3 and the optical fiber 2 at the optimum coupling position is L1 +
L2.

As shown in FIG. 5, the distance between the semiconductor laser device 1 and the optical fiber 2 at the optimum coupling position in the conventional optical system is L2. The fiber 2 can be separated from the conventional fiber by the distance L1, and a module having a high coupling efficiency can be obtained without damaging the semiconductor laser element 1 or the optical fiber 2 during adjustment.

As described above, the lens 3 is inserted between the semiconductor laser device 1 and the optical fiber 2 so as to keep the space between the semiconductor laser device 1 and the optical fiber 2 apart. And the optical fiber 2 is hardly damaged.

When the lens 3 is not provided, the semiconductor laser element 1 and the optical fiber 2 are very close to several μm to several tens μm. Can be spread out. Further, since the lens 3 is inserted, the semiconductor laser device 1 and the optical fiber 2 do not collide with each other.

FIG. 3 is a view showing a semiconductor laser module structure according to another embodiment of the present invention. In FIG. 3, in a semiconductor laser module structure according to another embodiment of the present invention, a semiconductor laser element 1 and a photodiode 8 fixed on a heat sink 11 are mounted in a subpackage 31 hermetically sealed with a lens 3. Have been.

The optical fiber 2 is fixed to the subpackage 31 via a fiber holder 32 by YAG welding (welding with a yag laser) or the like. At this time, the lens 3 is fixed between the subpackage 31 and the fiber holder 32.

The subpackage 31 to which the optical fiber 2 is fixed is fixed to the cooling-side substrate of the electronic cooler 10 by soldering. The electronic cooler 10 is fixed to the inner bottom surface of the module package 4 by soldering. The method of fixing the optical fiber 2 is not limited to the above method, and may be directly fixed to the carrier 7 as in the embodiment of the present invention.

When the lens 3 is not provided, the gap between the semiconductor laser device 1 and the optical fiber 2 is small, so that the optical fiber 2 and the module package 4 are sealed. In this case, it is necessary to metallize the optical fiber 2 in order to seal it with solder. In addition, residual stress is generated in the optical fiber 2 during cooling and fixing, which may cause a problem in reliability.

On the other hand, in the semiconductor laser module structure according to another embodiment of the present invention, by inserting the lens 3, the distance between the semiconductor laser element 1 and the lens 3 and between the lens 3 and the optical fiber 2 is increased. Is increased, the hermetic sealing can be performed using the lens 3. Therefore,
The hermetic sealing of the semiconductor laser device 1 can be easily performed.

In one embodiment of the present invention and another embodiment, the electronic cooler 10 is used. However, if a stable optical output and wavelength can be obtained, the electronic cooler 10 is not used as the non-cooled type. May be.

In the above description, the case where one lens 3 is used has been described. However, two or more lens systems such as a collimator lens having an image magnification of about 1 may be used as the lens 3. It is not limited to these. In the case where two or more lens systems are used, airtightness can be achieved in the entire module package by arranging other lenses except the first lens outside the module package.

[0032]

As described above, according to the present invention, in a semiconductor laser module including an optical fiber whose end face is processed into a tapered shape and a semiconductor laser element optically coupled to the optical fiber, a lens is formed of a semiconductor laser. By inserting the laser device and the optical fiber so as to separate them from each other and with a space between each of the semiconductor laser device and the optical fiber, damage to the semiconductor laser device and the optical fiber can be suppressed, and There is an effect that coupling efficiency can be obtained.

[Brief description of the drawings]

FIG. 1 is a view showing a semiconductor laser module structure according to one embodiment of the present invention.

FIG. 2 is a diagram showing an optical system of a semiconductor laser module structure according to one embodiment of the present invention.

FIG. 3 is a view showing a semiconductor laser module structure according to another embodiment of the present invention.

FIG. 4 is a diagram showing a semiconductor laser module structure according to a conventional example.

FIG. 5 is a diagram showing an optical system of a conventional semiconductor laser module structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser element 2 Optical fiber 3 Lens 4 Module package 7 Carrier 8 Photodiode 10 Electronic cooler 11 Heat sink 21 Tapered part 22, 32 Fiber holder 31 Subpackage

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04B 10/135 10/13 10/12

Claims (8)

[Claims] 1. A semiconductor laser module comprising: an optical fiber having an end face tapered, and a semiconductor laser device optically coupled to the optical fiber, wherein the semiconductor laser device and the optical fiber are connected to each other. A semiconductor laser module comprising a lens inserted at a distance from the semiconductor laser element and the optical fiber with a space interposed therebetween. 2. The semiconductor laser module according to claim 1, wherein said lens has an image magnification of approximately 1. 3. The semiconductor laser module according to claim 1, wherein said lens is arranged so that an image magnification becomes substantially 1. 4. The semiconductor laser according to claim 3, wherein said lens is disposed between said semiconductor laser element and said optical fiber with an interval of at least a focal length thereof. module. 5. The semiconductor laser module according to claim 1, further comprising a subpackage containing said semiconductor laser element and hermetically sealed with said lens. 6. The semiconductor laser module according to claim 5, further comprising a fiber folder fixed to said subpackage and holding said optical fiber. 7. The semiconductor laser module according to claim 1, wherein said lens comprises one lens. 8. The semiconductor laser module according to claim 1, wherein the lens comprises a plurality of lenses.