JPS62150208A - Connecting method for polarization plane maintaining optical fiber - Google Patents

Abstract

PURPOSE:To connect polarization plane maintaining optical fibers by coupling their optical power only, to eliminate the necessity of any rotating mechanism for optical axis alignment of the fibers, and to facilitate the alignment of their inherent polarization axes, by cutting an integrated body, inside which the core of the optical fiber is held between its 1st and 2nd fixing jigs, into two blocks and placing the cut faces of the two blocks on the 3rd fixing jig. CONSTITUTION:An optical fiber holder 9 composed of the 1st and 2nd fixing jigs 9a and 9b is provided with V-grooves 11 which can hold the core 10 of a polarization plane maintaining optical fiber 16 and grooves 13 which can hold the sheath 12 of the optical fiber 16. Firstly, a polarization plane maintaining optical fiber is put between the 1st and 2nd fixing jigs 9a and 9b of the holder 9 and firmly stuck to the jigs 9a and 9b with an epoxy bonding agent, etc., and thus, a integrated body 14 is prepared. Then the integrated body 14 is cut along the broken line, etc., by means of a diamond cutter, etc., and the integrated body 14 is divided into the 1st and 2nd constituting bodies 14a and 14b. Then the cut faces of the constituting bodies 14a and 14b are polished. After polishing, the constituting bodies 14a and 14b are put on an inherent polarization axis aligning jig 15 which becomes the 3rd fixing jig having the same shapes as those of the body 14 at its more than one faces and slid on the jig 15 so as to obtain optical coupling between them.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for connecting polarization-maintaining optical fibers, and more particularly to a method for easily aligning the principal axes.

BACKGROUND OF THE INVENTION Polarization-maintaining optical fibers propagate light while maintaining the polarization in the direction of its principal axis, and are therefore capable of large-capacity signal transmission. FIG. 3 shows a conventional example of a method for connecting polarization-maintaining optical fibers. It is assumed that the light emitted from the light source 1 is linearly polarized by the polarizer 2, and that this linearly polarized light is incident on the polarization-maintaining fiber 3 in the direction of its intrinsic polarization axis.

When connecting the polarization-maintaining optical fiber 3 and the polarization-maintaining fiber 4, the intrinsic polarization axis 1. y and the intrinsic polarization axis x'+ of the input side end face 6b of the polarization-maintaining optical fiber 4! /' respectively x/x', ,! //, // or x/: J', J/x' to align the intrinsic polarization axes, and then optical powers are combined to perform fusion splicing. Conventionally, this intrinsic polarization axis alignment has been carried out at the end surface Sa as shown in, for example, Japanese Patent Application Laid-Open No. 69-38709.

6b by checking the characteristic polarization axis with a microscope or the like, or by rotating the input end of the polarization preserving optical fiber 4 as shown in FIG.
The extinction ratio was measured by rotating the lens, and the rotation with the highest extinction ratio was determined to be the position where the eigenpolarization axis was precisely aligned.

Problems to be Solved by the Invention In such a conventional method for connecting polarization-maintaining optical fibers, the polarization-maintaining optical fibers 3 and 4 are connected by a manipulator or the like.
In addition to moving the optical axis parallel to and perpendicular to the optical axis, a rotation mechanism is also required. Furthermore, in the conventional example shown in FIG. 3, it is necessary to measure the extinction ratio.

The present invention has been made in view of the above points, and an object of the present invention is to provide a method for connecting polarization-maintaining optical fibers that facilitates alignment of the intrinsic polarization axis, especially when inserting an optical element in the middle of the optical path of the polarization-maintaining optical fiber. The purpose is

Means for solving the problems and technical means of the present invention for solving the above problems are as follows:
A part of the polarization-maintaining optical fiber was scissored and fixed with a first fixing jig and a second fixing jig, and the integrated product was cut in a plane that was not parallel to the optical axis, and then cut into two parts. The cut surfaces of the polarization-maintaining optical fiber structures are connected by optically coupling them on a third fixing jig, which preferably has one or more surfaces identical in shape to the integrated structure, so that their natural polarization axes are aligned.

Function According to the above-described connection method of the present invention, an integrated product in which the core wires are sandwiched by the first fixing jig and the second fixing jig is cut, and the same surface of the integrated product cut into two is cut into a third. The inherent polarization axes of the two polarization-maintaining optical fibers match just by placing them on the fixing jig, and the connection can be made simply by combining the optical power.
No rotation mechanism is required for optical axis alignment, making it easy to align the intrinsic polarization axis.

Embodiment FIGS. 1 and 2 are process diagrams of an embodiment for explaining the method for connecting polarization-maintaining optical fibers of the present invention. 1st
In the figure, a first fixing jig 9a, a second fixing jig 9b
The optical fiber holder 9 consists of a V-groove 11 that can hold the polarization-preserving optical fiber core 1o and a groove 13 that can hold the polarization-preserving optical fiber coating 12. Each fixing jig is made of a material such as glass, ceramic, or silicon substrate. It is equipped with The coating of a polarization preserving optical fiber coated with nylon, polyamide, etc. can be removed using concentrated sulfuric acid, and only a portion of the core wire 10 can be exposed.

First, attach the polarization preserving optical fiber to the optical fiber holder 9.
This is then fixed with scissors and epoxy adhesive, etc., to form an integrated product 14 as shown in FIG. 2a. Next, cut along the broken line part with a diamond cutter or the like, and cut the integrated part 14e No. 1.2.
g2 (DHi body 14a, 14b is divided into sections and the cross section is optically polished. Next, as shown in Fig. 2, the integrated body 14
The structure is divided into two parts 14&.

14b is placed on a unique polarization axis alignment jig 15 serving as a third fixing jig, which has the same shape on one side or more as the integrated object 14, and is slid to perform optical coupling. In this state, it is only necessary to couple the two divided polarization maintaining optical fibers. The unique polarization axis alignment jig 15 may be made of a flat plate material other than Lm shown in FIG. 2, or may be of a concave shape and provided with a slight clearance from the integrated object. It is still best to use glass, ceramic, stainless steel, etc. as the material.

Although the cross sections of the structures 14a and 14b obtained by dividing the integrated body 14 into two may be directly connected to each other, this method requires an optical element such as a Pockels element, etc. in the middle of the polarization maintaining optical fiber 16.
This is effective when inserting a Faraday element, a half mirror, etc., and the structure 14a.

It is preferable to fix a collimating lens to the cross section of 14b and insert an optical element between them. The unique polarization axis alignment jig 16 is
By dividing the jig into two parts and rotating the jig itself with mechanical precision, it is possible to align the unique polarization axis to any desired angle. The present invention can also be applied to black A-A, which has a collimating lens and one Faraday element between polarization-maintaining optical fibers set at 46°C.Effects of the InventionAs described above, according to the method of the present invention, the unique axis alignment method can be achieved. This method is particularly effective when inserting an optical element in the optical path of a polarization-maintaining optical fiber, and can realize a method for connecting polarization-maintaining optical fibers suitable for mass production.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view of an integrated optical fiber holder and polarization-maintaining optical fiber used in a method for connecting polarization-maintaining optical fibers according to an embodiment of the present invention, and Fig. 2 is a process step for explaining the connection method. The perspective view and FIG. 3 are configuration diagrams for explaining the conventional connection method. 9... Optical fiber holder, 9a, sb...
...Fixing jig, 1o...Polarization preserving optical fiber core, 11...V groove, 12...Polarization preserving optical fiber coating, 13... groove, 14
...Integrated object, 142L. 14b... Structure, 16... Unique polarization axis alignment jig. Name of agent: Patent attorney Toshio Nakao and 1 other person9-
1 Hikari-7 Finogu A-J Leg- % --- Rei I's Trouble L: ff3 A qb ---'l) Z's ・ Figure 2 (a+) 76 Noon Figure 3

Claims (2)

[Claims] (1) A part of the core wire of the polarization-maintaining optical fiber is fixed by scissoring with a first fixing jig and a second fixing jig, and the first,
The integrated body consisting of the second fixture and the core wire is cut along a plane that is not parallel to the optical axis to form two polarization-maintaining optical fiber structures, and these optical fiber structures are placed on a third fixture. A method of connecting polarization-maintaining optical fibers that performs optical coupling by placing (2) The method for connecting polarization-maintaining optical fibers according to claim 1, wherein the third fixing jig is divided into two.