JPH0894875A - Waveguide type optical module - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a waveguide type optical module capable of reducing stress applied to an optical component and obtaining good optical characteristics against temperature fluctuation. In a waveguide type optical module constructed by surrounding an optical component including a waveguide element connected to an optical fiber with a surrounding member, the surrounding member has a coefficient of linear expansion equivalent to that of other members. Formed of a material having a lower linear expansion coefficient than

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, and more particularly to a waveguide type optical module improved to obtain good optical characteristics against temperature fluctuations.

[0002]

2. Description of the Related Art With recent advances in optical communication technology, there is an increasing demand for a waveguide type optical module including an optical branching device, an optical multiplexer and the like. Along with this, high reliability and economical efficiency are required for the waveguide type optical module.

Conventionally, an example of this type of waveguide type optical module will be described with reference to FIG. In the waveguide type optical module of FIG. 2, the incident side fiber array 3 to which the incident side single-core optical fiber 1 is connected and the incident light is divided into four by using a Y branch.
The incident side of the waveguide element 5 which is divided and emitted is fixed by UV adhesive in a state where the optical axes are aligned, and the emission side of the waveguide element 5 and the four-core tape fiber 2 on the emission side are connected. The emission side fiber array 4 is fixed with a UV adhesive in a state where the optical axes are aligned with each other, thereby forming an optical unit.
In the case of the optical unit configured as described above, when used in a high temperature and high humidity atmosphere, the adhesive absorbs moisture to reduce the bonding strength between the optical fiber and the optical waveguide,
The optical unit is housed in a mounting package 6 made of plastic or metal and having a recess therein, and the bottom surface of the optical unit and the mounting package 6 are adhesively fixed, and then adhesively fixed and integrated by an adhesive from above and below. It was tightly sealed.

Further, instead of the mounting package, the optical unit is housed in a housing made of a metal material, and further filled with a jelly-like resin and sealed.
No. 139, the optical waveguide module disclosed in Japanese Patent Laid-Open No. 5-45531, or a part of the waveguide element, in which the surface of the optical unit is coated with a rubber-like silicone resin having a low water absorption rate. Only connected directly to the metal housing, see JP-A-63-205617
There was an optical waveguide module disclosed in the publication.

[0005]

According to the conventional optical waveguide module, the metal block or resin as a constituent element causes remarkable thermal expansion and contraction due to temperature change, and the remarkable thermal expansion and contraction causes This has given rise to the problem that stress is applied to the parts and the destruction and loss fluctuation of the optical parts become large.

In view of the above, an object of the present invention is to provide a waveguide type optical module which solves the above-mentioned problems by reducing the stress applied to optical parts and obtaining good optical characteristics against temperature fluctuations. To provide.

[0007]

A waveguide type optical module provided by the present invention is a waveguide type optical module constructed by surrounding an optical component including a waveguide element connected to an optical fiber with a surrounding member. The surrounding member is formed of a material having a linear expansion coefficient equal to or lower than that of other members.

It is desirable that the material of the surrounding member made of the material having the low linear expansion coefficient does not transform when the temperature is changed.

[0009]

According to the waveguide type optical module of the present invention, the waveguide type optical module is formed of a material having a coefficient of linear expansion equivalent to that of other members or a coefficient of linear expansion lower than that of other members. Since the thermal expansion and the thermal contraction are equal to or lower than those of other members, it is possible to prevent the deformation, increase in loss, and destruction of the waveguide element due to the remarkable thermal expansion and thermal contraction of the surrounding member. .

If the surrounding material made of a material having a low coefficient of linear expansion does not undergo a transformation when the temperature is changed, the thermal expansion of the surrounding member, even if the temperature fluctuation range becomes large,
Thermal shrinkage is kept low with a constant width.

[0011]

FIG. 1 shows an embodiment of the optical waveguide type optical module of the present invention. The optical waveguide type optical module of the present embodiment includes an incident side fiber array 3 to which the incident side single-core optical fiber 1 is connected, and an incident side light array 4 using Y branching.
The incident side of the waveguide element 5 which is divided and emitted is fixed by UV adhesive in a state where the optical axes are aligned, and the emission side of the waveguide element 5 and the four-core tape fiber 2 on the emission side are connected. An optical unit is constructed by fixing the exit side fiber array 4 and the optical axis with UV adhesive.
In this optical unit, when used in a high temperature and high humidity atmosphere, the adhesive absorbs moisture and the bonding strength of the bonding portion between the optical fiber and the optical waveguide is reduced. Therefore, the pedestal 7 is adhered to the bottom surface of the waveguide element 5, the optical unit is housed inside the enclosing member 6 composed of a housing, the pedestal 7 portion and the enclosing member 6 are adhesively fixed, and both ends of the enclosing member 6 are attached. Is packaged by hermetically sealing it with a lid 8 and is reinforced by an elastic body 10 such as a rubber tube to prevent the optical fiber from being broken.

In the optical waveguide type optical module having the above structure, the pedestal 7 is made of the same material as the waveguide element 5 in order to make its linear expansion coefficient substantially equal to that of the waveguide element 5, and is mounted. The surrounding member 6 which is a package for a material is a material having a low linear expansion coefficient, for example, Invar (Fe-36.
5Ni, linear expansion coefficient α = 1.2 × 10 ⁻⁶ ) is used.

In FIG. 3, the material of the surrounding member 6 is super invar (Fe32Ni, 5Co, linear expansion coefficient α = ±).
0.1 × 10 ⁻⁶ ), Invar (Fe-36.5Ni, linear expansion coefficient α = 1.2 × 10 ⁻⁶ ), SUS (18-8M)
o, the measurement data of the temperature characteristics when the linear expansion coefficient α = 16.2 × 10 ⁻⁶ ) is used. From FIG. 3, it can be seen that the loss fluctuation range is small, that is, Super Invar, Invar, and SU.
It can be seen that the order is S.

FIG. 4 shows measured dimensions of the surrounding member 6 when the temperature of the surrounding member 6 is lowered to -40.degree. From FIG. 4, it can be seen that the material of superimba transforms at around −40 ° C. and expands rapidly. It is considered that this is because cobalt is contained in the components of Super Inba.

In view of the above characteristics, it can be said that the envelope member 6 is optimally composed of Invar, which is compositionally stable and has a low linear expansion coefficient.

[0016]

According to the waveguide type optical module of the present invention as described above, the enclosing member to be a package for the optical component including the waveguide element is made of a material having a low linear expansion coefficient. Further, the thermal expansion and thermal contraction of the surrounding member become extremely small, the stress on the optical component is reduced, and it is possible to prevent damage and increase in loss caused by the deformation of the optical component.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of a waveguide type optical module according to the present invention.

FIG. 2 is an exploded perspective view showing an example of a conventional waveguide type optical module.

3A and 3B are explanatory diagrams showing measurement results of temperature characteristics in the waveguide type optical module shown in FIG. 1 by changing materials.

FIG. 4 is an explanatory view showing the temperature characteristic measurement results of the surrounding member in the waveguide type optical module shown in FIG. 1 with different materials.

[Explanation of symbols]

 1 single-core optical fiber on the incident side 2 4-fiber tape fiber on the emitting side 3 fiber array on the incident side 4 fiber array on the emitting side 5 waveguide element 6 enclosing member 7 pedestal 8 lid 10 elastic body (rubber tube)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinobu Kurosawa 5-1, 1-1 Hidaka-cho, Hitachi-shi, Ibaraki Hitachi Cable Co., Ltd. Optro System Research Laboratories (72) Inventor Ryuta Takahashi Hidaka-cho, Hitachi-shi, Ibaraki 5-1-1, Hitachi Cable Co., Ltd., Optro System Research Center

Claims (2)

[Claims] 1. A waveguide type optical module constructed by surrounding an optical component including a waveguide element connected to an optical fiber with a surrounding member, and the surrounding member has a linear expansion coefficient equivalent to that of other members. A waveguide type optical module characterized by being formed of a material having a linear expansion coefficient lower than that. 2. The waveguide type optical module according to claim 1, wherein the surrounding member made of a material having a low linear expansion coefficient does not transform when the temperature is changed.