JP2580922Y2 - Optical fiber fixing structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber fixing structure used for an optical system such as an optical fiber communication or an optical measuring instrument.

[0002]

2. Description of the Related Art Conventionally, as a technique for fixing an optical fiber, a method using an adhesive and a method using an alloy solder of lead and tin are generally known.

FIG. 2 is a longitudinal sectional view of an optical fiber fixing structure when an alloy solder of lead and tin is used. Optical fiber 11
Is fixed by inserting it into a hollow metal holding member 12 having a metal film 14 provided on the inner surface, and then filling a gap between the two members with an alloy solder 13 of lead and tin. In this case, the metal film 15 is formed on the side surface of the optical fiber 11 by a method such as evaporation.
Is provided.

On the other hand, when the structure is fixed with an adhesive, an adhesive is used instead of the alloy solder 13. In this case, the metal film 14 on the inner surface of the holding member 12 and the optical fiber 11
The metal film 15 on the side surface is unnecessary.

[0005]

In the conventional optical fiber fixing structure described above, when an adhesive is used,
Since adhesives generally have high hygroscopicity, they tend to be deformed or have a reduced adhesive strength under high humidity conditions. In addition, since the glass transition temperature is low, the maximum use temperature of an optical component using an adhesive is restricted. In addition, there is a problem in that the outgassing causes contamination of the optical surface in the vicinity, and thus there is a problem that long-term reliability is lacking.

In the case of using an alloy solder of lead and tin, which is widely used in general, see the literature (Mitomi et al., "A Consideration on a Screening Method for Solder-Fixed Optical Circuit Components", Transactions of the Institute of Electronics and Communication Engineers, March 1986. , VoL.J69-C, No.
3, pp. 297-303), since the alloy solder is a metal having a relatively low melting point, the solder is distorted with time especially when a load such as gravity is constantly applied to the solder joint. Creep phenomenon easily occurs.
Therefore, when the optical fiber is fixed with this alloy solder,
Since the position of the optical fiber changes with time, there is a problem that long-term stability of the optical system cannot be ensured. In addition, when there is a change in ambient temperature due to a change in environmental temperature or heat generated by an electronic circuit, a tensile and compressive stress is repeatedly applied to the solder joint. There is also a problem that the cracks are generated in the solder due to the mechanical fatigue, the position of the optical fiber is displaced, and the optical axis is shifted.

[0007]

An optical fiber fixing structure according to the present invention comprises: a hollow holding member comprising a cylindrical metal pipe and a ceramic pipe inscribed in the metal pipe;
An optical fiber inserted into the hollow holding member; and a low-melting glass used for a gap between the holding member and the optical fiber and joining the holding member and the optical fiber.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing one embodiment of an optical fiber fixing structure according to the present invention.

In this embodiment, a hollow holding member 2, an optical fiber 1 inserted into a hollow portion of the holding member 2, and a low-pitch member which is used in a gap between the holding member 2 and the optical fiber 1 and joins the two. And melting point glass 3. That is, the optical fiber 1 made of quartz glass has a tip portion processed into a tapered spherical shape, and after being inserted into a pipe-shaped holding member 2, the optical fiber 1 is made of low melting glass 3 containing lead glass as a main component. It is fixed by filling the gap between the fiber 1 and the holding member 2. Note that the configuration of the holding member 2 used in the present embodiment is such that a ceramic pipe 202 inscribed in a metal pipe 201 is fixed by a brazing material 203.

As described above, in the present embodiment, the low melting point glass 3 is used as a means for fixing the optical fiber 1. In the low melting point glass 3, the crystal structure after solidification is different from that of solder, and no creep phenomenon occurs. Therefore, the optical axis does not shift due to the displacement of the optical fiber 1.

[0012]

As described above, the present invention has the following effects by using a low-melting glass as a method for fixing an optical fiber. That is, since the low-melting glass has a different crystal structure from that of the solder material and does not cause a creep phenomenon, the optical axis of the optical fiber can be prevented from shifting with time. Therefore, there is an effect that the reliability of the optical component using the optical fiber can be improved. When the holding member has a structure in which a ceramic pipe is inscribed in a metal pipe, it has an effect of absorbing thermal strain generated when the optical fiber and the holding member are fixed with low-melting glass.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of an optical fiber fixing structure according to the present invention.

FIG. 2 is a longitudinal sectional view showing an example of a conventional optical fiber fixing structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1,11 Optical fiber 2,12 Holding member 3 Low melting glass 13 Alloy solder 14,15 Metal film 201 Metal pipe 202 Ceramic pipe 203 Brazing material

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02B 6/00 341 G02B 6/24 G02B 6/26 G02B 6/36

Claims (1)

(57) [Scope of request for utility model registration] A hollow holding member comprising a cylindrical metal pipe and a ceramic pipe inscribed in the metal pipe; an optical fiber inserted into the hollow holding member; An optical fiber fixing structure, comprising: a low-melting glass that is used in a gap and joins the holding member and the optical fiber.