JPS61239209A - Production of semiconductor laser and optical fiber coupling device - Google Patents

Abstract

PURPOSE:To improve the mass-productivity by sticking the first fixing member fixing a semiconductor laser and a lens and the second fixing member fixing a ferrule,where a fiber is stored, in such positions with a resin that the coupling efficiency is maximum and subjecting them to laser welding. CONSTITUTION:A semiconductor laser 2 and a lens holder 6 of a lens 5 are stuck to a package system to form the first fixing member. A ferrule 8 holding an optical fiber jacket 10 whose optical fiber strand 9 is exposed is adhered to a ferrule holder 7 with a resin 11 to form the second fixing member. The first and the second fixing members are adjusted finely in (x), (y), and (z) directions to attain positions of maximum coupling efficiency, and parts A and B are adhered with a resin, and they are stuck by laser welding. Thus, the degradation of the coupling efficiency during production is prevented to improve the mass-productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a device for coupling a semiconductor laser to an optical fiber.

2. Description of the Related Art In the past, various devices have been considered for coupling a semiconductor laser and an optical fiber, and FIG. 3 shows a vertical cross-sectional view of the structure of a typical device. In Fig. 3, 1 is a package stem, 2 is a semiconductor laser, 3 is a monitor light receiving element,
4 is an electrode, 6 is a ball lens, 6 is a lens holder, 7 is a ferrule holder, and 8 is a fer-! , 9 is an optical fiber wire,
1o is an optical fiber jacket. This structure is based on a concentric cylindrical shape centered on the optical axis. As a manufacturing method of this coupling device, first, the ball lens 6 is attached to the lens holder 6.
This lens-equipped holder is fitted and fixed into the package stem 1 to which the semiconductor laser 2 has been fixed in advance. The ball lens 5 is fixed to the lens holder 6 by resin adhesion.
By brazing, soldering, etc. Further, the lens holder 6 is fixed to the package stem 1 by resin adhesion, resistance welding, or the like. The optical axis deviation of the ball lens 6 causes an angular deviation of the g-condensed beam, which deteriorates the coupling efficiency, but the positional accuracy of the emission center of the semiconductor laser 2 is ±10.
If it is within 0 μm, package stem 1. The mechanical processing precision of the lens holder 6 sufficiently suppresses deterioration. On the other hand, the optical fiber wire 9 is fixed to the ferrule/L/8 with a resin adhesive, and is guided by the ferrule holder 7 with a clearance of about 2 μm. Fell here
/L/8 in the optical axis horizontal direction (two directions) and the optical axis vertical direction Cx, ! (direction) with a manipulator, and when the maximum coupling efficiency is achieved, completely fix the parts M and B in Figure 3 with resin adhesive, or temporarily fix them with resin adhesive and then fix them with resistance welding. (For example, Tachikawa, Saruwatari: 1988 IEICE Semiconductor and Materials Division National Conference 291).

Problems to be Solved by the Invention In such a conventional semiconductor laser/optical fiber coupling device, optical axis misalignment occurs due to the application of pressure, especially during resistance welding after fine adjustment of the ferrule 8 in the x, y, and z directions. It was necessary to adjust the pressure in the reservoir to reduce the welding strength and to maintain welding strength, and resistance welding was difficult unless a small amount of temporary fixing adhesive was applied. Furthermore, resistance welding was difficult to fix the ferrule holder 7 to the ferrule holder 7 due to its shape. Furthermore, in the case of resistance welding, each piece is sandwiched between jigs and welded under pressure, which is inferior in terms of mass production.On the other hand, fixing with resin bonding is a conventional method, but it has poor long-term reliability. There was a problem with that.

The present invention has been made in view of the above points, and an object of the present invention is to provide a semiconductor laser/optical fiber coupling device that is easy to manufacture, has little deterioration in coupling efficiency during manufacturing, and is excellent in mass productivity and long-term reliability. It is an object.

Means for Solving the Problems In order to solve the above problems, the present invention fixes the semiconductor laser and the lens using a first fixing jig, and fixes the optical fiber in parallel and perpendicular directions to the optical axis. A second fixing jig whose position can be adjusted is fixed to the first fixing jig with a resin adhesive at a position where the coupling efficiency is maximized, and further fixed by laser welding.

Function The present invention has the above-mentioned configuration, and since it is non-contact welding using a laser after the resin adhesive is fixed, no pressure is applied unlike resistance welding, and the welding heat input is much lower than other welding methods. Since the coupling efficiency is small, there is little deterioration in coupling efficiency during manufacturing, and since it is fixed to metal, it has excellent long-term reliability, and the use of numerical control tables etc. can improve mass production.

Embodiment FIG. 1 shows a method of manufacturing a semiconductor laser/optical fiber coupling device according to an embodiment of the present invention.

This will be explained with reference to FIG. Since the structure shown in FIG. 1 is almost the same as that shown in FIG. 3 as a conventional example, explanation of the common parts will be omitted. 11 is a resin adhesive, and α and β are laser welding beams. Package stem 1. Semiconductor laser 29 ball lens 5. The lens holders 6 are fixed to each other, and the optical fiber strand 9 is fixed to the fer/L' 8. Fer-/l
/8 is guided by the ferrule holder 7 with a clearance of about 2 μm, and is held at the position of maximum coupling efficiency by finely adjusting it in the x, y, and Z directions using a manipulator to hold the fer-)vB. At this point, parts A and B are fixed with a resin adhesive. After the resin adhesive has solidified, it is fixed by laser welding. As long as the resin adhesive does not absorb the laser welding beam, it may be applied to the entire circumference, and welding is performed through the resin adhesive.

If the resin adhesive absorbs the laser welding beam, apply it at appropriate intervals and weld the parts where there is no resin adhesive.

YAG laser (λ=1.06am
) is better than CO21z-the (λ= 10.6 μm)
There is less reflection on the metal surface compared to , making it easier to weld. For example, in the case of stainless steel, the reflectance is FJeo% for λ-1.06 μm, and that for λ = 10.6 μm is FI
At 90%, YAG laser is more suitable.

Considering reflectance, coefficient of thermal expansion that causes deterioration of coupling efficiency due to temperature changes, ease of processing, rust, etc., fixing jigs such as lens holder 6 and ferrule holder 7 should be made of stainless steel. Are suitable.

As for resin adhesives, for example, ultraviolet curable adhesives can control the degree of hardening depending on the amount of ultraviolet rays, and can be used for final curing while correcting optical axis deviation caused by resin contraction due to curing using a manipulator. This is advantageous when coupling a semiconductor laser to a single-mode optical fiber that requires severe coupling conditions.

The welded part of the ferrule holder 7 is made of stainless steel (5US303) with a thickness of o and 4 mm, and an ordinary ultraviolet curable adhesive is applied to the entire circumference as a resin adhesive.
(The tensile strength is 950 kg when welding with the lens holder 6 at 8 points equally spaced using an r laser is 950 kg. Here, the pulsed YAG laser is used, and the pulse intensity is 5 m5 ec.

Repetition: 10 pp8, Lens: f5Qmm, 1xE
This is done using approximately 45 energy per 17 tons. Mechanical strength can be further increased by seam welding the entire circumference.

Welding of the ferrule holder 7 and the ferrule holder 7 was performed in the same way, and when a single mode optical fiber with a core diameter of 10 μm was coupled, the coupling efficiency was approximately -s, sdB, and the output fluctuation was 0 to 0.
It is about ±0.5 dB at 50°C.

If there is a gap between the contact surfaces of the ferrule holder 7 and the lens holder 6, welding will not be possible, so in order to ensure reliable welding, a protrusion as shown in Figure 1 is provided on the ferrule 8, and first the maximum coupling efficiency is achieved. After fixing only the A part in two directions at the position with resin adhesive, welding it in advance, press the protrusion against the lens holder 6 with a spring, and fix it with the resin adhesive with the ferrule holder 7 completely attached. It's good to do it. Further, FIG. 2 is a longitudinal sectional view showing the direction of the laser welding beam depending on the thickness of the ferrule holder 7. It depends on the energy of the laser welding beam, but if it is thin,
Alternatively, if the energy is high, it is possible to weld as in e), but if the material is thick or it is difficult to weld using method (&), welding can be performed as in (b). Generally, method (b) is strong, but any method may be used as long as the required strength can be obtained. The black part is the welded part.

After being fixed with resin adhesive, it can be removed from the manipulator and laser welded, so mass production can be improved by using a numerical control table or the like. When the energy of the laser welding beam is high, even though the resin adhesive is used, distortion may occur due to welding, reducing the coupling efficiency. However, by simultaneously welding two or four diagonal lines on the circumference, deterioration in coupling efficiency can be suppressed.

Effects of the Invention As described above, according to the present invention, it is possible to realize a semiconductor laser/optical fiber coupling device that is easy to manufacture, has little deterioration in coupling efficiency during manufacturing, and is excellent in mass productivity and long-term reliability. .

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a semiconductor laser/optical fiber coupling device for explaining the manufacturing method of the semiconductor laser/optical fiber coupling device in one embodiment of the present invention, and FIG. 2 is a longitudinal cross-section of a laser welded portion by the same method. The plan view and FIG. 3 are longitudinal sectional views of a semiconductor laser/optical fiber coupling device for explaining a conventional manufacturing method. 2... Semiconductor laser, 5... Ball lens, 6... Lens holder, 7... Ferrule holder, 8... Ferrule, 9・・・・・・
・Optical fiber wire, 11...Resin adhesive. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 5-11 Engineering East Building Figure 2 CQ-) (b)

Claims (5)

[Claims] (1) a semiconductor laser, an optical fiber, and a lens that focuses the light emitted from the semiconductor laser onto the optical fiber;
a first fixing member that fixes the semiconductor laser and the lens; and a second fixing member that fixes the optical fiber to the first fixing member so that the position of the optical fiber can be adjusted in parallel and perpendicular directions with respect to the optical axis. a fixing member, the second fixing member is connected to the first fixing member;
A method for manufacturing a semiconductor laser/optical fiber coupling device, which comprises fixing the semiconductor laser to the fixing member using a resin adhesive at a position where the coupling efficiency is maximum, and further fixing by laser welding. (2) The semiconductor laser and light according to claim 1, wherein the resin adhesive has a low absorption of laser light for laser welding, and the laser welding is performed through the resin adhesive. A method of manufacturing a fiber coupling device. (3) The method for manufacturing a semiconductor laser/optical fiber coupling device according to claim 1 or 2, wherein the resin adhesive is an ultraviolet curable adhesive. (4) The method for manufacturing a semiconductor laser/optical fiber coupling device according to claim 1, 2, or 3, wherein the laser welding is YAG laser welding. (5) Claims 1, 2, and 3, characterized in that the first and second fixing members are made of stainless steel.
A method for manufacturing a semiconductor laser/optical fiber coupling device according to item 1 or 4.