JPH0545531A - Optical waveguide circuit module - Google Patents

Abstract

PURPOSE:To offer the optical waveguide circuit module which is economical and has high reliability. CONSTITUTION:An optical waveguide chip 7 and 8-unit fiber ribbons 9 and 10 for light input and output which are fitted to the optical waveguide chip 7 having their optical axes aligned are sealed by the coating 15 of a resin composition together with a housing wherein they are stored and held to secure the mechanical strength and weatherability of connection parts between the optical waveguide chip 7 itself and 8-unit fiber ribbons 9 and 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an economical and highly reliable optical waveguide circuit module in which an optical waveguide chip and an optical fiber connected thereto are integrated.

[0002]

2. Description of the Related Art With the progress of optical communication technology in recent years, high economic efficiency and reliability are required for optical waveguide circuits such as optical branching elements and optical multiplexers. This type of optical waveguide circuit is generally constructed by connecting an optical fiber for optical input / output to the end face of an optical waveguide chip. In configuring these optical waveguide circuits, the connection between the optical waveguide chip and the optical fiber is the most important part that determines its reliability.

Conventionally, the entire optical waveguide chip including the vicinity of the connection portion with the optical fiber is housed in a mounting package to improve the mechanical strength and weather resistance of the optical waveguide circuit, especially the connection portion, and to improve reliability. It was common to increase.

FIG. 2 shows an example of a conventional optical waveguide circuit module, which is often adopted when there are only a few optical fibers to be connected to one end face of the optical waveguide chip. Indicates. In the figure, reference numeral 1 is a silica-based optical waveguide chip having a 1 × 2 splitter structure formed on a silicon substrate, and optical fibers 2, 3 and 4 for optical input and output have their optical axes aligned with their end faces. As described above, they are connected / fixed by the adhesive 5, and the whole of them are housed / sealed in the mounting package 6 made of plastic or metal.

As described above, in the optical waveguide circuit module in which the optical fiber is directly connected to the optical waveguide chip, in order to secure the mechanical strength and weather resistance of the optical waveguide chip itself and the connecting portion with the optical fiber, the mounting is performed. It was essential to put it in a package.

FIG. 3 shows another example of a conventional optical waveguide circuit module, in which a relatively large number of optical fibers, for example, 8-core or 16-core tape fibers, should be connected to one end face of an optical waveguide chip. Shows the form often adopted in. In the figure, 7 is a silica-based optical waveguide chip formed on a silicon substrate, and an optical waveguide chip housing 8 is provided.
It is held and fixed to. Further, 9 and 10 are 8-core tape fibers, the ends of which are the optical fiber end case 1
They are held and fixed to 1 and 12, respectively. In addition, the optical waveguide chip casing 8 and the optical fiber end casing 11,
12 is connected to the end face of the optical waveguide chip 7 via an ultraviolet-curing adhesive 13 so that the optical axes of the 8-core tape fibers 9 and 10 coincide with each other, and the whole of them is made of plastic or metal. It is housed and sealed in the mounting package 14.

The casings 8, 11 and 12 are each made of Pyrex glass and have a substantially rectangular U-shaped cross section.
a, 11a, 12a and fixing plates 8b, 11b, 12b also made of Pyrex glass, which are adhered and fixed by an adhesive (not shown).

As described above, in the optical waveguide circuit module in which the optical waveguide chip and the optical fiber are housed and held in the optical waveguide chip casing and the optical fiber end casing, respectively, and then connected, the mounting package is particularly used. It is possible to maintain the mechanical strength of the optical waveguide chip itself and the connection with the optical fiber without using it. However, when the adhesive used for forming each housing and connecting between each housing is placed in a high temperature and high humidity environment, the adhesive absorbs moisture and the adhesive strength decreases with time. In the circuit module as well, in order to ensure the weather resistance of each part of the housing and the connection part, it is essential to store it in a mounting package.

[0009]

As described above, in the conventional optical waveguide circuit module, the cost of components is increased by the amount of the mounting package, and the number of steps of mounting work is increased, so that the economical efficiency is sacrificed. There was a problem.

In view of the above conventional problems, it is an object of the present invention to provide an economical and highly reliable optical waveguide circuit module.

[0011]

In order to achieve the above object, the present invention provides claim 1 as an optical waveguide chip and an optical fiber for optical input / output which is mounted on the optical waveguide chip so that their optical axes coincide with each other. In an optical waveguide circuit module comprising: an optical waveguide circuit module in which the entire optical waveguide chip including the vicinity of a connection portion with an optical fiber is coated and sealed with a resin composition, and a coating is provided as claim 2. The layer is composed of at least two layers, the lowermost layer is composed of a resin composition whose glass transition temperature is lower than the lower limit of the operating environment temperature, and the uppermost layer is a resin composition whose glass transition temperature is higher than the upper limit of the operating environment temperature. The constructed optical waveguide circuit module according to claim 1 is proposed.

[0012]

According to the first aspect of the present invention, by providing the coating layer of the resin composition, the mechanical strength of the optical waveguide chip itself and the connecting portion with the optical fiber is secured without using a mounting package. In addition, it is possible to prevent the infiltration of water into the adhesive, which is a major cause of the deterioration of the reliability of the connection portion, and it is possible to improve the resistance to moisture and heat and improve the reliability. Further, according to claim 2, a portion of the coating layer, which is in contact with the optical waveguide chip, the optical fiber or the connecting portion thereof, is made of a resin composition which is sufficiently soft at the ambient temperature of use,
Further, since the outside is made of a resin composition that is sufficiently hard at the ambient temperature of use, mechanical strength can be secured without applying stress to each component or its connecting portion.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first optical waveguide circuit module of the present invention.
In the figure, the same components as those in the conventional example of FIG. 3 are represented by the same reference numerals. That is, 7 is an optical waveguide chip, 8 is an optical waveguide chip housing, 9 and 10 are 8-core tape fibers, 11 and 12 are optical fiber end housings, 13 is an adhesive, and 15 is a coating layer.

The optical waveguide chip 7, the optical waveguide chip housing 8, the 8-core tape fibers 9 and 10 and the optical fiber end housings 11 and 12 are assembled in the same manner as in the conventional example, and are bonded by an adhesive 13. It is adhered and fixed to form the basic module A.

The coating layer 15 is formed by integrally forming the resin composition over the entire surface of the above-mentioned basic module A and sealing the resin composition. Here, since the basic module A has relatively high mechanical strength, the coating layer 15 is a resin composition whose main purpose is to ensure weather resistance, specifically, to prevent the intrusion of water, for example, a small water absorption. It has a single-layer structure made of rubber-like silicone resin. The coating layer 15 is formed by immersing the entire basic module A in the solution of the silicone resin and drying it.

FIG. 4 shows the results of measuring the change in loss increase when the optical waveguide circuit modules of this embodiment and the conventional example of FIG. 3 are left in a high temperature and high humidity environment of 70 ° C. and 90%. In the figure, 16 indicates the characteristic of this embodiment, and 17 indicates the characteristic of the conventional example.

As shown in FIG. 4, in the conventional example, the leaving time is 10
It is understood that the loss increases sharply when the time exceeds 0 hours, but in the present example, the increase in the loss can be suppressed to 0.2 dB or less up to 750 hours. From this, it is understood that the optical waveguide circuit module of the present embodiment can significantly improve the moisture resistance characteristics of the component.

A heat cycle test was conducted on the optical waveguide circuit module of this example.
The loss variation was as small as 0.1 dB or less over the temperature range of 80 ° C., confirming the effect of providing the coating layer made of the resin composition.

The coating layer of this embodiment has a single-layer structure composed only of the resin composition whose main purpose is to secure weather resistance as described above, but a multilayer structure as shown in a second embodiment described later. Also good.

FIG. 5 shows a second embodiment of the present invention. In the figure, the same components as those of the conventional example of FIG. That is, 1 is an optical waveguide chip, 2, 3 and 4 are optical fibers, 5 is an adhesive, and 18 is a coating layer.
The optical waveguide chip 1 and the optical fibers 2, 3 and 4 are assembled in the same manner as in the conventional example, and adhered and fixed by the adhesive 5 to form the basic module C.

The coating layer 18 is formed by integrally forming the resin composition over the entire surface of the basic module C and sealing it. Here, since the basic module C has relatively weak mechanical strength, the coating layer 18 is required to have weather resistance and mechanical strength. Coating layer 1 to ensure mechanical strength
Although it is necessary to make 8 hard enough, on the other hand, it is required that the stress from the coating layer 18 is not applied to the optical waveguide chip, the optical fiber, or their connecting portion.
Therefore, the coating layer 18 has a two-layer structure including a first coating layer 18a that is sufficiently soft at the operating environment temperature and a second coating layer 18b that is sufficiently hard at the operating environment temperature.

The first coating layer 18a is disposed inside the entire coating layer 18, that is, in a portion in contact with an optical waveguide chip, an optical fiber or a connecting portion thereof,
The second coating layer 18b is arranged on the outside thereof.
As the resin composition forming the first and second coating layers 18a and 18b, the present optical waveguide circuit module is -1.
Assuming that it is used in the temperature range of 0 ° C to 80 ° C,
The first coating layer 18a has a glass transition temperature (Tg
) Is a rubber-like silicone resin whose temperature is −10 ° C. or lower,
Further, an epoxy resin having a glass transition temperature of 100 ° C. or higher is used for the second coating layer 18b. All of these resin compositions have a low water absorption.

The coating layer 18 is formed by
The entire basic module C is dipped in the solution of the silicone resin and dried to form a first coating layer 18a, and the first coating layer 18a is further formed.
The basic module C having formed therein is dipped in the solution of the epoxy resin and dried to form the second coating layer 18b.

FIG. 6 shows the result of measuring the change in loss increase when the optical waveguide circuit modules of this embodiment and the conventional example of FIG. 2 are left in a high temperature and high humidity environment of 70 ° C. and 90%. In the figure, 19 indicates the characteristic of the present embodiment, and 20 indicates the characteristic of the conventional example.

As shown in FIG. 6, in the conventional example, the leaving time is 40
It is understood that although the loss increases sharply when the time is exceeded, the increase of the loss can be suppressed to 0.2 dB or less up to 500 hours in this embodiment. From this, it is understood that the optical waveguide circuit module of the present embodiment can significantly improve the moisture resistance characteristics of the component.

A heat cycle test was conducted on the optical waveguide circuit module of this example.
The loss variation was as small as 0.1 dB or less over the temperature range of 80 ° C., and the effect of using a substance having a low glass transition temperature as the lower layer having a two-layer structure was confirmed.

As described above, the coating layer of this embodiment has a two-layer structure composed of two kinds of resin compositions whose main purpose is to secure mechanical strength and weather resistance.
It may have a multi-layered structure of three or more layers. In this case, as the resin composition constituting the intermediate layer, its glass transition temperature is
It is desirable to use a material that is between the glass transition temperature of the resin composition forming the lowermost layer and the glass transition temperature of the resin composition forming the uppermost layer.

FIG. 7 shows a third embodiment of the present invention, in which 21 is an optical waveguide chip, 22, 23 and 24 are optical fibers, 25 is an interference film filter, and 26 and 27 are adhesives. 28 is a coating layer.

The optical waveguide chip 1 is of a quartz type formed on a silicon substrate, and has guide grooves 21a, 21b, 21c for inserting an optical fiber and a guide groove 21d for inserting a filter. The guide grooves 21a, 21
The ends of the optical fibers 22, 23, and 24 are inserted into b and 21c, respectively, and adhered and fixed by an adhesive 26, and the interference film filter 25 is inserted into the guide groove 21d and adhered by an adhesive 27. It is fixed and constitutes a basic module E having a wavelength multiplexing / demultiplexing function.

The coating layer 28 is formed by integrally forming the resin composition over the entire surface of the basic module E and sealing the resin composition. Here, the coating layer 28 is for the purpose of ensuring mechanical strength and weather resistance.
It has a two-layer structure similar to that of the second embodiment.

As in the case of the first or second embodiment, the change in loss increase amount when the optical waveguide circuit module was left in a high temperature and high humidity environment of 70 ° C. and 90% was measured.
It was found that the increase in loss could be suppressed to 0.2 dB or less by 00 hours and high reliability could be obtained.

In the above description, the silicone resin and the epoxy resin are used as the resin composition, but the resin composition is not limited to these, and various resin compositions such as fluororubber, urethane resin, acrylic resin, etc. Can be applied.

[0033]

As described above, according to the optical waveguide circuit module of the first aspect of the present invention, the entire optical waveguide chip including the vicinity of the connecting portion with the optical fiber is coated with the resin composition and sealed. Without using a mounting package, it is possible to secure the mechanical strength and weather resistance of the optical waveguide chip itself and the connection portion with the optical fiber, and therefore, without increasing the component cost and the number of steps of mounting work. It is possible to provide an economical and highly reliable optical waveguide circuit module.

Further, according to the optical waveguide circuit module of claim 2 of the present invention, the coating layer is composed of at least two layers, and the lowermost layer is composed of a resin composition whose glass transition temperature is lower than the lower limit of the ambient temperature for use. However, since the uppermost layer is made of a resin composition whose glass transition temperature is higher than the upper limit of the operating environment temperature, the optical waveguide chip or the optical fiber or the connecting portion thereof is not stressed, and the optical strength is high. A wave circuit module can be realized.

[Brief description of drawings]

1A and 1B are configuration diagrams showing a first embodiment of an optical waveguide circuit module of the present invention, in which FIG. 1A is a perspective view and FIG. 1B is an arrow BB in FIG. 1A. Cross-section view

FIG. 2 is a configuration diagram showing an example of a conventional optical waveguide circuit module.

FIG. 3 is a configuration diagram showing another example of a conventional optical waveguide circuit module.

FIG. 4 is a graph showing measurement results of humidity resistance characteristics of the first example and the conventional example of FIG.

5A and 5B are configuration diagrams showing a second embodiment of the optical waveguide circuit module of the present invention, wherein FIG. 5A is a perspective view and FIG. 5B is a line D-D arrow in FIG. 5A. Cross-section view

FIG. 6 is a graph showing measurement results of moisture resistance characteristics of the second example and the conventional example of FIG.

7A and 7B are configuration diagrams showing a third embodiment of the optical waveguide circuit module of the present invention, FIG. 7A is a perspective view before coating, and FIG. 7B is a perspective view after coating.

[Explanation of symbols]

1, 7, 21 ... Optical waveguide chip, 2, 3, 4, 22, 2
3, 24 ... Optical fiber, 5, 13, 26, 27 ... Adhesive agent, 8 ... Optical waveguide chip housing, 9, 10 ... 8-core tape fiber, 11, 12 ... Optical fiber end housing, 15,
18, 28 ... Coating layer, 25 ... Interference membrane filter.

Claims (2)

[Claims] 1. An optical waveguide circuit module comprising an optical waveguide chip and an optical fiber for optical input / output, which is attached to the optical waveguide chip so that the optical axes thereof coincide with each other, including a portion near a connecting portion with the optical fiber. An optical waveguide circuit module, wherein the entire optical waveguide chip is coated with a resin composition and sealed. 2. The coating layer is composed of at least two layers, the lowermost layer is composed of a resin composition whose glass transition temperature is lower than the lower limit of the operating environment temperature, and the uppermost layer has a glass transition temperature of the upper limit of the operating environment temperature. The optical waveguide circuit module according to claim 1, wherein the optical waveguide circuit module is composed of a higher resin composition.