JPH0728089B2 - Optical component manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] At the time of manufacturing an optical component, heat cycle annealing is performed after each step of fixing each component constituting the optical component or at a position with the strictest tolerance. As a result, internal strain caused by mechanical and thermal causes at the time of fixing can be efficiently removed, and a highly reliable optical component with little characteristic fluctuation after completion can be obtained.

[Industrial application field]

The present invention relates to a method of manufacturing an optical component, and more particularly to a method of manufacturing an optical component that can maintain the accuracy of each fixed component in an optical coupling system of the optical component stably for a long period of time.

Optical parts (light emission of LD, APD, etc., light receiving device, optical switch,
Demand for optical branching / coupling devices (such as optical couplers) is increasing as components for optical system configuration with the development of optical communication, and it is required to mass-produce highly reliable optical components. . In addition, the optical components mounted in the optical repeater required in the optical submarine communication system are required to have a particularly long life and are required to have the same or higher reliability as the conventional electrical components for the coaxial system. For this reason, it is necessary to develop a method for manufacturing an optical component having high reliability, particularly, a method for manufacturing an optical component that can maintain the accuracy of each fixed part in an optical coupling system stably over a long period of time. is necessary.

In this case, optical components, unlike electrical components, require precision on the order of submicrons for adjustment and fixing in the assembly of the optical coupling system, and in order to maintain such precision and increase reliability,
Special consideration is required for the manufacturing method.

[Conventional technology]

When manufacturing an optical component, generally used is a method of assembling by fixing each part constituting the optical component with a method such as screwing, soldering, laser welding or the like.

The finished products that have undergone the individual steps are usually subjected to high-temperature storage screening at a higher temperature than in actual use to select those of good quality (small deterioration in light output).

[Problems to be Solved by the Invention] When assembling an optical component, when each component is fixed, internal strain due to mechanical and thermal causes remains each time.

Since such intrinsic strain is released during high-temperature storage screening performed on the finished product and in the subsequent usage environment, the relaxation of the strain causes changes in shape and dimensions, and the optical axis in the optical coupling system is changed. There is a problem that deviation occurs and characteristic deterioration occurs.

In general, optical parts tend to change with time even on the low temperature side. Therefore, the effect of improving the reliability of optical parts can be improved only by the screening method by leaving them at high temperature, which is generally used in the past. Little. Further, the high temperature storage test has a drawback that the acceleration rate is small and the screening requires a long time.

Furthermore, the screening method using a completed product has a drawback that the product yield is low.

[Means for solving problems]

In order to solve the problems of the prior art as described above, the present invention is provided with each means as shown in the principle configuration shown in FIG.

After performing the process of fixing each piece, heat cycle annealing with the highest acceleration is performed on the optical component.

The above procedure is incorporated into the assembly process.

Reference (Mitomi et al., "A device for screening of solder-fixed optical components" IEICE Technical Report R84-33 (October 1984)) [Operation] When assembling optical components by joining and fixing multiple parts, each part Since the heat cycle annealing is performed after the fixing process of the piece is completed, the strain caused by the mechanical and thermal causes caused by the fixing process is removed. Moreover, the creep of the fixed part (primary creep) is also effectively removed.

Further, since the optical axis shift in the previous process can be recovered by adjusting the subsequent process, the product yield is improved as compared with the conventional method using only the completed product screening. The variation of the shape and dimension based on the residual strain is likely to occur in the initial stage after the completion of the manufacturing of the finished product. However, in the method of the present invention, the heat cycle annealing is performed after the completion of the piece fixing step. Can be reliably removed.

〔Example〕

FIG. 2 shows an example of the structure of an LD module to which the present invention is applied. In the figure, 1 is an LD chip, which is mounted on a substrate 2 made of metal.
Reference numeral 3 denotes a first lens holding member made of metal, which fixes the first lens 4 made of a glass ball into a circular hole at the center of the upper portion by press fitting or the like, and adheres to the substrate 2 around the lower portion thereof,
It is fixed by soldering. 5 is a glass window 5 '
And a second lens holding cylinder 6 made of metal, in which a second lens 7 made of a glass ball is attached to a central through hole, and a lower part of the periphery of the same is sealed. It is fixed to the upper portion of the cap 5 by soldering or the like. Reference numeral 8 denotes an optical fiber holding cylinder made of metal, in which a fiber sheath 9 made of metal is inserted into a through hole in the center, and the lower periphery thereof is adhered and soldered to the upper part of the second lens holding cylinder 6. It is fixed by etc. The fiber sheath 9 has an optical fiber 10 in its center hole.
And the periphery of the upper part is fixed to the upper part of the optical fiber holding tube 8 by soldering or the like.
Reference numeral 12 denotes an LD drive terminal that supplies a drive current for operating the LD chip 1. In FIG. 2, the mark * represents the above-mentioned fixing portion. It should be noted that the joining and fixing of the respective parts in these respective parts are not limited to soldering or the like,
It goes without saying that other joining methods such as laser welding may be used.

FIG. 3 shows one embodiment of the present invention (an example in which heat cycle annealing is performed for each fixing), and illustrates the process of manufacturing the LD module shown in FIG. That is, after mounting the LD chip 1 on the substrate 2, the following steps are performed.

(1) First lens holding member 3 to which the first lens 4 is attached
Is fixed to the substrate 2 (step S1).

(2) Perform heat cycle annealing (Step S
2).

(3) The airtight sealing cap 5 is fixed to the substrate 2 (step S3).

(4) Perform heat cycle annealing (Step S
Four).

(5) The second lens holding cylinder 6 having the second lens 7 mounted thereon is fixed to the airtight sealing cap 5 (step S5).

(6) Perform heat cycle annealing (Step S
6).

(7) The optical fiber holding barrel 8 is fixed to the second lens holding barrel 6 (step S7).

(8) Heat cycle annealing (step S
8).

(9) The fiber sheath 9 having the optical fiber 10 inserted therein is fixed to the optical fiber holding tube 8 (step S9).

(10) A heat cycle for screening a completed product is performed (step S10).

(11) Characteristic inspection is performed (step S11).

(12) The quality of the optical component is determined (step S12).

In the method for manufacturing an optical component of the present invention, after removing the internal strain by performing heat cycle annealing at each end of the step of fixing each piece in this manner, the process proceeds to the step of fixing the next piece. Has become. An example of heat cycle annealing in the manufacturing process will be described below.

(Example of Heat Cycle Annealing) FIG. 4 and FIG. 5 show an example of the heat cycle annealing conditions in the present invention.

In FIG. 4, a indicates the temperature range of the heat cycle annealing of the present invention, which is wider on the low temperature side and on the high temperature side than the heat cycle for screening shown in b, whereby sufficient strain removal is achieved. It is experimentally confirmed that the effect of However, it goes without saying that the set temperatures on the high temperature side and the low temperature side take into consideration the temperature at which the optical fiber is not damaged. c indicates the operating temperature range for the LD module.

Fig. 5 shows an example of a temperature cycle, in which the temperature is raised from a low temperature to a high temperature over a predetermined time and then kept in that state for a predetermined time.
Next, it is shown that a cycle of lowering the temperature to a low temperature again for a predetermined time, maintaining the state for a predetermined time, and raising the temperature again is repeated. The number of temperature cycles is experimentally determined, and may be, for example, several tens of times.

By performing the heat cycle annealing in each of the piece fixing steps in this manner, residual internal strain is prevented, and characteristic deterioration due to strain relaxation in the finished product does not occur.

〔The invention's effect〕

As described above, according to the present invention, since the heat cycle annealing is performed for each execution of the step of fixing each component forming the optical component or for the most severe tolerance, the intrinsic strain generated in each component fixing step is Each time it is removed, no strain remains when the assembly is completed, and the creep of the fixed part is also removed. Therefore, according to the method of the present invention, (1) an optical component having high reliability can be realized.

(2) Various variations due to the manufacturing process are reduced, and the quality is stable.

(3) The yield at the time of screening a finished product is improved.

And so on.

[Brief description of drawings]

FIG. 1 is a flow chart showing the basic configuration of the present invention, FIG. 2 is a diagram showing an example of the structure of an optical component (LD module) to which the present invention is applied, and FIG. 3 is an LD of an embodiment of the present invention. FIG. 4 is a flowchart showing a module manufacturing process, FIG. 4 is a diagram showing an example of a temperature range of heat cycle annealing, and FIG. 5 is a diagram showing an example of a temperature cycle. 1 ... LD chip 2 ... Substrate 3 ... First lens holding member 4 ... First lens 5 ... Security sealing cap 5 '... Glass window 6 ... Second lens holding tube 7 ... Second lens 8 …… Optical fiber holding tube 9 …… Fiber sheath 10 …… Optical fiber 12 …… LD drive terminal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Mitomi 3-9-11 Midoricho, Musashino-shi, Tokyo Inside Nippon Telegraph and Telephone Corporation Electronic Engineering Research Laboratory (72) Kenji Kono 3-Chome Midoricho, Musashino-shi, Tokyo 9-11, Nippon Telegraph and Telephone Corporation, Electronic Engineering Laboratory

Claims (2)

[Claims] 1. In an optical component manufacturing process in which a plurality of pieces are joined and fixed to assemble an optical component, the step comprises a plurality of steps for fixing each piece, and the tolerance is the strictest after each step of fixing each piece. A method of manufacturing an optical component, comprising performing heat cycle annealing on a portion and then moving to the next step to assemble the optical component. 2. The temperature range of the heat cycle annealing is wider on each of the lower temperature side and the higher temperature side than the temperature range of the heat cycle for screening at the completion of the optical component. A method of manufacturing an optical component according to item 1.