JPH06342108A - Waveguide type optical module - Google Patents

Abstract

PURPOSE:To improve reliability by eliminating the influence of a distortion by a temp. change. CONSTITUTION:This waveguide type module is constituted by combining a waveguide element, glass fibers cord 12, etc., which are plural optical parts and housing these optical parts into a hollow metallic casing 17 for protection. The plural optical parts are adhered and fixed to each other by adhesives and only the waveguide element is fixed to the hollow metallic casing 17 to support the other parts on the casing 17 side. A silicone resin 19 having a low modulus of elasticity is packed into the excess space of the housing 17 to enclose and fix the respective parts. As a result, the influence of thermal expansion, etc., of the hollow metallic casing 17 with the temp. change extends only on the waveguide element and does not extend to the other parts. Consequently, the junctures between the respective optical parts are not affected at all and the connection loss by misalignment of the optical axes and angle breakage, etc., is minimized. The respective parts are enclosed by the silicone resin 19, by which the strength to withstand impact from the outside is greatly increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide type optical module capable of suppressing deterioration of optical characteristics to a minimum with respect to a rapid temperature change.

[0002]

2. Description of the Related Art An example of a waveguide type optical module having a plurality of optical components is a waveguide type optical multiplexer / demultiplexer. In this waveguide type optical multiplexer / demultiplexer, a single-core optical fiber, a plurality of optical fibers, and an optical waveguide element are separately formed into blocks,
They are connected to each other. Each block is normally aligned and fixed with an accuracy of several μm in order to maintain optical coupling.

Specifically, as shown in FIG. 5, the element wire 1A of the single-core optical fiber 1 on the incident side is inserted into and bonded to a metal block 2 for protection. The optical waveguide 3 is inserted in and adhered to the metal block 4, and the emission side fiber array 5 is inserted in and adhered to the metal block 6, respectively. Fiber array 5
A four-core tape fiber 7 is connected to.

The end faces of the metal blocks 2, 4 and 6 are respectively polished, and the metal blocks 2 and 6 are abutted on both sides of the metal block 4 of the optical waveguide 3 at the center to adjust the optical axis. The abutting portions of the blocks 2, 4 and 6 are welded with a YAG laser to integrally fix them.

[0005]

By the way, since the metal blocks 2, 4 and 6 for protecting the respective optical parts are made of metal, thermal expansion and contraction occur due to temperature changes. The optical fiber 1 inserted and adhered inside due to this expansion and contraction
Etc. will be distorted. Under the influence of this distortion, there is a problem in that the optical axis is adjusted, the optical axis is displaced, the angle is broken, etc., and the connection loss is increased.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a waveguide type optical module in which distortion due to temperature change is eliminated and reliability is improved.

[0007]

In order to solve the above problems, the present invention provides a waveguide type optical module in which a plurality of optical components are combined and housed in a protective hollow casing. It is characterized in that the optical components are adhered and fixed to each other with an adhesive, and one of the optical components is fixed to the hollow casing to support the plurality of optical components on the hollow casing side.

It is desirable that the surplus space of the hollow housing be filled with a resin having a low elastic modulus to wrap and fix the optical component.

[0009]

[Function] One of the optical components integrally bonded and fixed
Since it is fixed to the side of the hollow casing through the two, the influence of thermal expansion of the hollow casing due to temperature change affects only one optical component and does not extend to other components. As a result, there is no influence on the connection portion between the optical components, and the connection loss due to the deviation of the optical axis or the bending of the angle can be minimized.

Further, by filling the excess space of the hollow casing with a resin and wrapping and fixing the optical component, the strength against the impact from the outside is significantly increased.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In this embodiment as well, a waveguide type optical multiplexer / demultiplexer will be described as a waveguide type optical module, as in the prior art. FIG. 1 is a side sectional view showing a state where an optical unit is mounted in a hollow metal housing, and FIG. 2 is a plan view showing the optical unit.

Reference numeral 11 in FIG. 2 denotes a waveguide element, which divides one light into 16 pieces. Reference numeral 12 is an incident side single-core optical fiber through which light of a plurality of wavelengths passes. This single-core optical fiber 12
Is fixed to one side surface of the waveguide element 11 with an adhesive in a state where the fiber element wire 12A is aligned with the optical axis of the waveguide element 11.

An optical fiber array 13 is attached to the other side surface of the waveguide element 11, and is fixed by an adhesive in a state where the optical axes are aligned with the 16 optical axes. 1
Reference numeral 4 denotes a four-core tape fiber, and four four-core tape fibers 14 are connected to the optical fiber array 13, respectively.

The waveguide element 11 and the single-core optical fiber 1
2. Optical fiber array 13 and four-core tape fiber 14
The optical unit 16 is configured by. The optical unit 16 is housed in a protective case. Specifically, it is as shown in FIG. Reference numeral 17 in the drawing denotes a protective hollow metal housing, which is formed into a hollow cylindrical shape as a whole, and the optical unit 16 is housed and fixed therein. The optical unit 16 has a hollow metal housing 17 via a pedestal 18 so as not to be affected by thermal expansion and contraction of the hollow metal housing 17.
Has been fixed. The hollow metal housing 17 side of the pedestal 18 is directly bonded and fixed to the hollow metal housing 17 with an adhesive, and the optical unit 16 side is bonded and fixed only to the waveguide element 11 with an adhesive.

Further, with the optical unit 16 housed in the hollow metal housing 17, the elastic modulus is 0.1 in the surplus space.
The silicon resin 19 of kg / mm ² is filled.

In the waveguide type optical multiplexer / demultiplexer having the above-described structure, when the temperature changes, the hollow metal housing 17 thermally expands or contracts. However, the expansion and contraction influences the hollow metal housing 17 differently. It is absorbed with the silicone resin 19. Further, there is almost no influence via the pedestal 18, and a slight influence is limited to the waveguide element 11. As a result, the connection portion between the waveguide element 11 and the single-core optical fiber 12 and the connection portion between the waveguide element 11 and the optical fiber array 13 are not affected by expansion and contraction, and the optical axis shift, the angle bending, etc. Suppress the occurrence.

As a result, the connection loss can be minimized, and the reliability of the device can be greatly improved.

Further, the hollow metal casing 17 is filled with a silicone resin 19 so that the optical unit 16 is filled with the silicone resin 19.
Since it is wrapped in and firmly supported, the strength of the waveguide type optical module against external impact can be greatly improved.

Next, FIG. 3 shows the results of examining the temperature characteristics of the waveguide type optical module having the above structure. The test was performed by placing a waveguide type optical module in a thermostat and changing the temperature at regular intervals. The temperature change is as shown in FIG.
1 step is 20 minutes, and 25 ° C constant is 1 step, 2
One step temperature change from 5 ℃ to -20 ℃, -20 ℃
1 step for constant, 1 step for temperature change from -20 to 65 ° C, 1 step for 65 ° C constant, 25 from 65 ° C
The temperature characteristic of the waveguide type optical module was examined by setting the temperature change to ° C as one step and performing the above two cycles as one cycle. The results are shown in FIGS. 3 (b) and 3 (c). In the conventional waveguide type optical module shown in FIG. 3B, the loss fluctuation width due to temperature change is large, whereas in the waveguide type optical module of the present embodiment shown in FIG. 3C, the loss variation is large. It can be seen that the fluctuation range is within ± 0.1 dB.

Next, FIG. 4 shows a change in the loss variation characteristic due to a difference in elastic modulus of the resin with which the hollow metal casing 17 is filled. As can be seen from this result, the loss fluctuation range is smaller as the elastic modulus is lower. Therefore, the resin with which the hollow metal housing 17 is filled is a resin having a low elastic modulus such as silicon resin.

In the above-mentioned embodiment, the waveguide type optical multiplexer / demultiplexer has been described as an example of the waveguide type optical module, but the present invention is not limited to this, and protection by thermal expansion and contraction by combining a plurality of optical components. If it is a waveguide type optical module configured to be housed in a hollow housing for use, the same operation and effect as described above can be obtained.

Further, in the above-mentioned embodiment, the structure in which the optical unit 16 is protected by the hollow metal housing 17 which is a metal protection member has been described. When used, the same operation and effect as described above can be obtained by adopting the constitution of the present invention.

[0023]

As described in detail above, according to the waveguide type optical module of the present invention, a plurality of optical components are bonded and fixed to each other with an adhesive, and one of the optical components is fixed to the hollow casing. By doing so, multiple optical components are supported on the side of the hollow housing, so there is little effect from thermal expansion and contraction, connection loss can be minimized, and device reliability is greatly improved. You can

Further, by filling the excess space of the hollow casing with a resin having a low elastic modulus and wrapping and fixing the optical component, the strength of the waveguide type optical module against an external impact can be greatly improved.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a waveguide type optical module according to the present invention.

FIG. 2 is a plan view showing an optical unit of the waveguide type optical module of FIG.

FIG. 3 is a graph showing temperature characteristics of a waveguide type optical module.

FIG. 4 is a graph showing changes in loss fluctuation characteristics depending on the difference in elastic modulus of the resin with which the hollow metal housing is filled.

FIG. 5 is a side sectional view showing a conventional waveguide type optical module.

[Explanation of symbols]

 11 Waveguide element 12 Single-core optical fiber 13 Optical fiber array 16 Optical unit 17 Hollow metal housing 18 Pedestal 19 Silicon resin.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinobu Kurosawa 5-1-1 Hidaka-cho, Hitachi-shi, Ibaraki Hitachi Cable Co., Ltd.

Claims (2)

[Claims] 1. A waveguide type optical module in which a plurality of optical components are combined and housed in a protective hollow casing, wherein the plurality of optical components are adhered and fixed to each other with an adhesive, A waveguide-type optical module, wherein one is fixed to the hollow housing to support a plurality of optical components on the hollow housing side. 2. The waveguide type optical module according to claim 1, wherein the excess space of the hollow casing is filled with a resin having a low elastic modulus, and the optical component is wrapped and fixed. module.