JPH0667030A - Structure for absorbing volume expansion in case of optical waveguide device - Google Patents

Abstract

PURPOSE:To suppress the rise of the pressure of inert gas in a case due to heat, to protect the sealed part of the case and to maintain the airtightness of the case. CONSTITUTION:A hole 8 is stepwise pierced in the central par of the bottom of a lower case member 3, this hole 8 is covered with a flexible plate 9 of phosphor bronze, etc., and a sealing member 10 is fixed into the gap between the lower case member 3 and the flexible plate 9 in contact with each other. An adhesive 11 is further filled into the gap between the flexible plate 9 and the sealing member 10 in contact with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a volume expansion absorbing structure in a case of an optical waveguide device used for optical communication.

[0002]

2. Description of the Related Art An optical waveguide device has a rectangular parallelepiped case, an inert gas is filled in the case, and an optical waveguide substrate having a flat optical waveguide formed on a base provided inside the case is arranged. It is constructed and set up. In the conventional optical waveguide device, no means for absorbing the volume expansion in the case due to heat is provided.

[0003]

In the prior art, the inert gas in the case is volume-expanded by heat, which causes pressure to be applied to the case and the bush or the seal portion such as the bush and the optical fiber, so that the seal portion is not formed. There is a problem that the airtightness in the case may not be maintained due to destruction.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to suppress the pressure increase of the inert gas in the case due to heat, and It is intended to provide a volume expansion absorption structure in a case of an optical waveguide device capable of maintaining airtightness.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an optical system for splitting one optical signal into a plurality of optical signals, or conversely combining a plurality of optical signals as one optical signal. In the volume expansion absorption structure in the case of the waveguide device,
A flexible plate is installed on one surface of the case instead of the case member.

A cylinder communicating with the outside air may be formed in the case, and a piston for shutting off the outside air from the inside of the case may be slidably fitted in the cylinder.

[0007]

[Function] Even if the pressure of the inert gas in the case rises due to heat to expand the volume, the volume in the case expands due to the expansion of the flexible plate to the outside air side or the sliding of the piston to the outside air side. The pressure inside the case does not rise.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a plan sectional view of a volume expansion and absorption structure in a case of an optical waveguide device according to claim 1, FIG. 2 is a side sectional view of the same, and FIG. 3 is a volume expansion and absorption structure in a case of an optical waveguide device according to claim 2. Fig. 4 is a horizontal sectional view, and Fig. 4 is a rear view.
FIG. 5 is an enlarged cross-sectional view of an essential part of FIG. 3, and FIG. 6 is a plan cross-sectional view of an optical waveguide device to which the volume expansion absorption structure in the case of the optical waveguide device according to the present invention is applied.

The optical waveguide device 1 includes an upper case member 2
And a lower case member 3 to form a rectangular parallelepiped case 4,
A flat optical waveguide 7 formed on an optical waveguide substrate 6 for dividing one optical signal into four optical signals is arranged on a base 5 provided inside a case 4 in which an inert gas is sealed. Has been done. The optical waveguide 7 is formed on the optical waveguide substrate 6 as a region having a higher refractive index than the surroundings by the ion exchange method.

According to a volume expansion absorbing structure for a case of an optical waveguide device according to a first aspect, as shown in FIGS. 1 and 2, a part of the central portion of the bottom surface of the lower case member 3 is opened stepwise, and the opening is formed. 8 is covered with a flexible plate 9 such as phosphor bronze, a seal member 10 is fitted in a contact portion between the lower case member 3 and the flexible plate 9, and an adhesive agent 11 is filled in a contact portion between the flexible plate 9 and the seal member 10. Is configured.

With the above structure, even if the pressure of the inert gas in the case 4 rises due to heat to expand the volume, the expansion of the flexible plate 9 to the outside air causes the volume in the case 4 to expand. The pressure inside the case 4 does not rise.

In the volume expansion absorbing structure for a case of an optical waveguide device according to a second aspect, as shown in FIGS. 3 and 4, the inside of the case 4 communicates with the outside air at the corners of the bottom and side surfaces of the lower case member 3. Cylinder 15 for forming
5, a piston 16 that shuts off the outside air from the inside of the case 4 is slidably fitted. As shown in FIG. 5, the cylinder 15 is made of a metal tube, and the piston 16 is made of a piston rod 17 and a seal packing 18.

With the above construction, even if the pressure of the inert gas in the case 4 rises due to heat to expand the volume, the volume inside the case 4 expands due to the sliding of the piston 16 toward the outside air. The pressure inside the case 4 does not rise.

FIG. 6 shows an optical waveguide device 1 to which the present invention is applied, in which an input optical fiber cable 20 is provided inside a case 4 via a bush 21 provided at a boundary between the upper case member 2 and the lower case member 3. And is fixed to the base 5 by the support 22 and the presser 23 and the support 24 and the presser 25 which are fixed to the base 5. Further, the optical fiber 26 exposed by stripping off the coating of the input optical fiber cable 20 is fixed by a pedestal 27 fixed to the base 5 and a presser 28, and the tip end surface of the optical fiber 26 corresponds to one of the optical waveguides 7. After being mechanically connected to the end faces, they are adhesively fixed with an adhesive 29.

Also, four optical fiber cables 30 for output are inserted into the case 4 through the bushes 21 like the optical fiber cable 20 for input, and each optical fiber cable 30 is attached to the base 5. Fixed cradle 2
It is fixed with 2 and the presser foot 23. Further, the optical fiber 31 exposed by peeling off the coating of the optical fiber cable 30 is fixed by a pedestal 32 fixed to the base 5 and a presser 33, and the front end surface of the optical fiber 31 is mechanically attached to the other end surface of the optical waveguide 7. After being electrically connected, they are adhesively fixed with an adhesive 29.

In the optical waveguide device 1 configured as described above, even if the pressure of the inert gas in the case 4 rises due to heat to expand the volume, the flexible plate 9 extends to the outside air side and the piston 16 Of the case 4 to the outside air side expands the volume in the case 4 and the pressure in the case 4 does not rise. Therefore, no pressure is applied to the case 4 and the bush 21, or the seal portion such as the bush 21 and the optical fiber cables 20 and 30. However, there is no case where the seal portion is broken and the airtightness inside the case 4 is not maintained.

[0017]

As described above, according to the present invention, even if the pressure of the inert gas in the case rises due to heat to expand the volume, the expansion of the flexible plate to the outside air side and the outside air side of the piston are performed. Since the volume inside the case expands due to sliding to, the pressure inside the case does not rise, so unnecessary pressure is not applied to the seal part such as the case and bush or the bush and optical fiber cable, and the seal part is not adversely affected. The airtightness inside the case is maintained.

[Brief description of drawings]

FIG. 1 is a plan sectional view of a volume expansion absorbing structure in a case of an optical waveguide device according to claim 1.

FIG. 2 is a side sectional view of the volume expansion absorbing structure in the case of the optical waveguide device according to claim 1.

FIG. 3 is a plan sectional view of a volume expansion absorbing structure in a case of the optical waveguide device according to claim 2;

FIG. 4 is a rear view of the volume expansion absorbing structure in the case of the optical waveguide device according to claim 2;

5 is an enlarged cross-sectional view of a main part of FIG.

FIG. 6 is a plan sectional view of an optical waveguide device to which a volume expansion absorbing structure in a case of the optical waveguide device according to the present invention is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical waveguide device, 2 ... Upper case member, 3 ... Lower case member, 4 ... Case, 9 ... Flexible plate,
15 ... Cylinder, 16 ... Piston.

Claims (2)

[Claims] 1. A volume expansion absorption structure in a case of an optical waveguide device for dividing one optical signal into a plurality of optical signals, or conversely coupling a plurality of optical signals as one optical signal, wherein: A volume expansion absorption structure in a case of an optical waveguide device, characterized in that a flexible plate is installed on one surface instead of a case member. 2. An in-case volume expansion absorption structure of an optical waveguide device for dividing one optical signal into a plurality of optical signals, and conversely coupling a plurality of optical signals as one optical signal, in the case To form a cylinder that communicates with the outside air,
A volume expansion absorption structure in a case of an optical waveguide device, characterized in that a piston for shutting off the outside air from the inside of the case is slidably fitted in the cylinder.