JPH0527139A - Optical waveguide circuit module - Google Patents

Abstract

PURPOSE:To provide an optical waveguide circuit module which maintains high reliability for a long period even in high-temperature and high-humidity conditions. CONSTITUTION:An optical waveguide chip 1 and end parts of ribbons of four- coated optical fibers for optical input and output are held and fixed to an optical waveguide chip housing 2 and optical fiber end part housings 5 and 6 respectively, the optical waveguide chip housing 2 and optical fiber end part housings 5 and 6 are connected so that the optical axes of the ribbons 3 and 4 of four-coated optical fibers for optical input and output are aligned with the end surface of the optical waveguide chip 1, and they are all put in an external housing 10, which is sealed with jelly resin 20, thereby preventing the infiltration of water into adhesives between and in the respective casings.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a 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 reliability is 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 an end face of an optical waveguide chip. Adhesives are extremely frequently used materials in constructing these optical waveguide circuits, and are important factors that determine the reliability of parts.

2 and 3 show an example of a conventional optical waveguide circuit module, in which a silica-based optical waveguide chip 1 formed on a silicon substrate is held in an optical waveguide chip housing 2.
After fixing and holding and fixing the ends of the optical fibers for optical input and output, here the four-core tape fibers 3 and 4, in the optical fiber end casings 5 and 6, respectively, the end face of the optical waveguide chip 1 is fixed. The optical waveguide chip housing 2 and the optical fiber end housings 5 and 6 are connected via an ultraviolet curing adhesive 7 so that the optical axes of the four-core tape fibers 3 and 4 coincide with each other. ing.

The casings 2, 5 and 6 are each made of Pyrex glass and have a substantially U-shaped cross section.
a, 5a and 6a and fixing plates 2b, 5b and 6b also made of Pyrex glass, which are adhered and fixed by adhesives 2c, 5c and 6c, respectively.

[0005]

However, in the above-mentioned optical waveguide circuit module, the adhesive 7 absorbs moisture in the presence of water, especially under high temperature and high humidity conditions, and the adhesive force decreases over time, and therefore the light transmission is reduced. There is a problem in that the optical waveguide chip casing 2 and the optical fiber end casings 5 and 6 are separated from each other when the rate is reduced or, in the case of remarkable decrease. Also, the adhesive 2c, 5c
Similarly, since the adhesive strength of 6 and 6c decreases with time,
There was a problem of low reliability.

It is to be noted that a case has been proposed in which the optical waveguide chip casing 2 and the optical fiber end casings 5 and 6 are connected by YAG laser welding without using an adhesive agent. Since an adhesive is used in each of the casings 2, 5 and 6 as described above, there is a problem that high reliability cannot be obtained.

In view of the above conventional problems, it is an object of the present invention to provide an optical waveguide circuit module capable of ensuring high reliability for a long period of time even under high temperature and high humidity conditions.

[0008]

In order to achieve the above object, the present invention provides, as claim 1, an optical waveguide chip and an optical input / output device which is mounted on an end face of the optical waveguide chip so that their optical axes coincide with each other. In an optical waveguide circuit module including an optical fiber, while holding and fixing the ends of the optical waveguide chip and the optical fiber for optical input / output to the optical waveguide chip housing and the optical fiber end housing, respectively, The optical waveguide chip housing and the optical fiber end housing are connected so that the optical axes of the optical fibers for optical input and output are aligned with the end surface of the optical waveguide chip, and the entire housing is housed in an external housing.
The sealed optical waveguide circuit module, and the optical waveguide circuit according to claim 1, wherein a resin composition is filled between the optical waveguide chip casing and the optical fiber end casing and the outer casing. A module and, as Claim 3, an optical waveguide circuit module according to Claim 2, which uses a resin composition having a glass transition temperature equal to or lower than a lower limit of a use environment temperature.

[0009]

According to the first aspect of the present invention, not only the adhesive used between the optical waveguide chip housing and the optical fiber end housing, but also the moisture for the adhesive used inside each housing. It is possible to prevent the infiltration of the resin, and to prevent the decrease in the adhesive force. Further, according to claim 2, it is possible to more reliably prevent the intrusion of moisture, suppress the cost increase due to the sealing as compared with the case of performing the airtight sealing, and achieve the economicalization of parts. it can. As the resin composition used here, of course, a material having low water absorption is suitable. Further, according to claim 3, there is no possibility that stress due to the glass transition of the resin composition will be applied to each component in the external housing, and there is no risk of increasing loss or damage.

[0010]

1 and 4 show a first embodiment of an optical waveguide circuit module of the present invention. In the drawings, the same components as those of the conventional example are designated by the same reference numerals. That is, 1 is an optical waveguide chip, 2 is an optical waveguide chip housing, 3 and 4 are 4-core tape fibers, 5 and 6 are optical fiber end housings, 7 is an adhesive,
Reference numeral 10 is an external housing, 20 is a resin composition, and here is a jelly-like resin.

The optical waveguide chip 1, the optical waveguide chip housing 2, the four-core tape fibers 3 and 4 and the optical fiber end housings 5 and 6 are assembled in the same manner as in the conventional example, and an adhesive 7 is used. It is adhered and fixed to form the basic module A.

The outer casing 10 comprises two units 11 and 12 having a similar shape.
Denoted at 2 are recesses 11a and 12 capable of accommodating the above-mentioned basic module A with some allowance when combined with each other.
a and notch 1 for taking out the four-core tape fibers 3 and 4
1b and 12b. The units 11 and 12 are made of metal, for example, stainless steel in consideration of moisture resistance.

The jelly-like resin 20 is for filling and sealing the inside of the outer casing 10, that is, the space between the recesses 11a and 12a and the basic module A, and has a low water absorption and a glass transition. An olefinic jelly resin having a temperature of -10 ° C is used.

The basic module A is housed and sealed inside the units 11 and 12 of the outer casing 10 via a jelly-like resin 20. Unit 11 and unit 12
Are connected by an adhesive 13, and at this time, the gap between the notch and the four-core tape fibers 3, 4 is also filled by the adhesive 13. A bisphenol epoxy resin is used as the adhesive 13.

Here, the reason why the jelly-like resin 20 having a glass transition temperature of −10 ° C. is used is that parts such as the optical waveguide chip 2 or the optical waveguide chip housing 2 and the optical fiber end housing 5 are used due to thermal expansion. This is to prevent stress from being applied to the connection part with the first and the sixth connection parts.

That is, the optical waveguide circuit module is used in various environments, but there is no particular limitation on the thermal properties of the resin composition at this temperature at room temperature or higher. However, when used in an environment at a temperature lower than room temperature, the optical waveguide chip 2 has a difference in linear expansion coefficient between silicon and glass, which form a component, and the linear expansion coefficient of the resin composition.
In some cases, stress may be applied to the connection parts and the like to increase the loss. To avoid this, the glass transition temperature (T
Assuming that the material having g), specifically, the present module is used in the temperature range of 0 to 60 ° C., the jelly-like resin 20 having a glass transition temperature of −10 ° C. was used as described above. The resin composition has a clear glass transition temperature Tg.
If not, the softening temperature is applied instead.

FIG. 5 shows the results of measuring the change in loss increase when the optical waveguide circuit modules of this example and the conventional example were left in a high temperature and high humidity environment of 70 ° C. and 90%. , 31 show the characteristics of this embodiment, and 32 shows the characteristics of the conventional example.

From FIG. 5, the leaving time is 10 in the conventional example.
It is understood that the loss increases sharply after 0 hour, but in the present embodiment, the increase in loss is suppressed to 0.2 dB or less up to 750 hours. From this, it can be seen that the optical waveguide circuit module of this embodiment can significantly improve the moisture resistance 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 + 70 ° C., and the effect of using the jelly resin as the sealing material was confirmed.

Further, in the first embodiment, the external housing 10
As the basic module to be housed and sealed in, the optical waveguide chip casing and the optical fiber end casing are connected by an adhesive, but those connected by YGA welding may be used.

FIG. 6 shows the same measurement results as in FIG. 5 in the case of using a basic module in which the optical waveguide chip housing and the optical fiber end housing are connected by YGA welding. Shows the characteristics when it is housed and sealed in an external housing as in the first embodiment, and 34 shows the characteristics when there is no external housing as in the conventional example.

From FIG. 6, in the conventional example, the leaving time is 50
It can be seen that the loss gradually increases after 0 hours. It is considered that this is because the adhesive for fixing the optical fiber in the housing for the end portion of the optical fiber deteriorated due to humidity. On the other hand, in this embodiment, 1000
It can be seen that the loss does not increase even if left for a long time in a high humidity and high temperature environment, and extremely high reliability is obtained.

FIG. 7 shows a second embodiment of the present invention, in which a heat shrinkable tube is used as an external housing for accommodating and sealing the basic module. That is,
In the figure, 40 is an external housing made of a heat shrink tube,
The basic module A has an inner diameter that can be accommodated with a certain amount of room, and the ends 41 and 42 corresponding to the four-core tape fibers 3 and 4 are shrunk by applying heat from the outside to accommodate and seal the basic module A. It seems to do. The same jelly-like resin as described above is filled and sealed between the external housing 40 and the basic module A. The gap between the outer casing 40 and the four-core tape fibers 3 and 4 is sealed with a sealing material 43 similar to the adhesive 13. As the heat shrinkable tube, for example, fluorine resin, polyolefin rubber, neoprene rubber or the like is used.

When the measurement described with reference to FIGS. 5 and 6 was carried out for this example, it was confirmed that almost the same moisture resistance characteristics as in the case of the first example were obtained.

Although the olefinic jelly resin is used as the sealant in each of the above-mentioned embodiments, the present invention is not limited to this, and various resin compositions can be applied.
Specifically, oil-based resin compositions such as silicone oil, rubber-like resin compositions such as silicone rubber and fluororubber, gel-like resin compositions such as silicone gel and acrylic gel, epoxy resin and synthetic rubber as the main components. Examples of adhesives are

[0026]

As described above, according to the first aspect of the present invention, the optical waveguide chip and the optical fiber for optical input / output mounted on the end face of the optical waveguide chip so that their optical axes coincide with each other. In the provided optical waveguide circuit module, while holding and fixing the optical waveguide chip and the end portion of the optical fiber for optical input / output to the optical waveguide chip casing and the optical fiber end portion casing, respectively, Since the housing and the housing for the optical fiber end portion are connected to the end face of the optical waveguide chip so that the optical axes of the optical fibers for optical input and output match, and the whole of them is housed and sealed in the external housing, Not only the adhesive used between the optical waveguide chip housing and the optical fiber end housing, but also the water used in the inside of each housing can be prevented from entering the adhesive, and the adhesive strength can be prevented from decreasing. It is possible The reliability can be greatly improved.

Further, according to the second aspect of the present invention, since the resin composition is filled between the casing for the optical waveguide chip and the casing for the optical fiber end portion and the outer casing, the moisture resistance can be improved and the component can be improved. Can be made economical.

Further, according to claim 3 of the present invention, since the resin composition whose glass transition temperature is lower than or equal to the lower limit of the operating environment temperature is used, the stress due to the glass transition of the resin composition is applied to each component in the external housing. Therefore, there is no risk of increasing loss or damage, and thus reliability can be further improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of an optical waveguide circuit module of the present invention.

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

FIG. 3 is an exploded perspective view of the optical waveguide circuit module shown in FIG.

FIG. 4 is an exploded perspective view of the optical waveguide circuit module shown in FIG.

FIG. 5 is a graph showing measurement results of moisture resistance characteristics when the optical waveguide chip casing and the optical fiber end casing are connected with an adhesive.

FIG. 6 is a graph showing measurement results of moisture resistance characteristics when the optical waveguide chip housing and the optical fiber end housing are connected by YAG welding.

FIG. 7 is a configuration diagram showing a second embodiment of an optical waveguide circuit module of the present invention.

[Explanation of symbols]

1 ... Optical waveguide chip, 2 ... Optical waveguide chip housing, 3,
4 ... 4-core tape fiber, 5, 6 ... Optical fiber end case, 7 ... Adhesive agent, 10, 40 ... External case, 20 ... Jelly resin.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tetsuo Yoshizawa             1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation

Claims (3)

[Claims] 1. An optical waveguide circuit module comprising an optical waveguide chip and an optical fiber for optical input / output, which is attached to an end face of the optical waveguide chip so that its optical axes coincide with each other. While holding and fixing the ends of the optical fibers for use in the optical waveguide chip casing and the optical fiber end casing, respectively, the optical waveguide chip casing and the optical fiber end casing are
An optical waveguide circuit module, characterized in that an end face of an optical waveguide chip is connected so that an optical axis of an optical fiber for optical input / output coincides with each other, and the whole is housed / sealed in an external housing. 2. The optical waveguide circuit module according to claim 1, wherein a resin composition is filled between the casing for the optical waveguide chip and the casing for the optical fiber end portion and the outer casing. 3. A resin composition having a glass transition temperature lower than or equal to the lower limit of the operating environment temperature is used.
The optical waveguide circuit module described.