JP2001228358A - Manufacturing method of optical fiber ferrule assembly equipped with angle index for indicating polarization plane direction of optical fiber, assembly component and assembling tool to be used therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical fiber ferrule assembly equipped with an angle index for indicating polarization plane direction of optical fibers, component parts used for the method, and an assembling tool to be used in the method. SOLUTION: The ferrule assembly manufactured by the invented method is provided with a polarization-plane-holding optical fiber, an optical fiber ferrule 1 for receiving the optical fiber and fixedly holding it with the tip end face exposed, and an angle index member 2; the assembly itself is rotatable with respect to the ferrule, containing the angle index member 2 that is fixed at a specific angular position to the polarization plane of the optical fiber. The angle index member 2 is combined to a tentative assembly of an optical fiber ferrule to which the optical fiber is fixed; in a state where either the member or the assembly is fixed, the tip end face of the optical fiber is observed in an expanded fashion so that, from its shape, the polarization plane direction is determined; and, the angle index is rotated relatively so that it is at a specific angle to the polarization plane direction, the angle index and the optical fiber are then fixed each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical fiber ferrule assembly provided with an angle index for indicating the polarization plane direction of an optical fiber in a fiber assembly using a stress imparting member such as a PANDA optical fiber. And a jig used in the method.

[0002]

2. Description of the Related Art In the fields of optical measurement and optical communication, a polarization plane maintaining optical fiber capable of transmitting while maintaining the polarization plane direction of the optical fiber is known. Polarization-maintaining optical fibers are widely used in the field of coherent communication where the state of polarization is a problem, and in the field where the characteristics of optical devices and the like depend on the polarization state of input / output light.

A polarization maintaining optical fiber can be realized by using a birefringent fiber. The structure of the polarization maintaining optical fiber using the birefringent fiber is classified into two types: a stress applying type optical fiber and a core shape deformed from a circle like an ellipse. At present, PANDA fiber (Polarization-maintaining AND Absorption-reduc
Since this is the case, the structure will be briefly described with reference to FIG. This PANDA fiber 100
Stress applying members 103A, 10A in the cladding 102
3B is glass of a material having a higher coefficient of thermal expansion than the surrounding silica glass. When the fiber is drawn at a high temperature and becomes a fiber and cools, the contraction of the stress applying member is larger than that of the surroundings, so that the core 101 is pulled in the Y direction, and accordingly, a compressive stress is generated in the X direction. As a result, the refractive index of the core 101 is different between the X direction and the Y direction due to the photoelastic effect, and the propagation constant of the propagating polarization mode is different. Various other methods have been studied depending on the method of applying stress, but at present, the following two types other than the PANDA type are in practical use. The bowtie shape, in which the stress applying member has a sector shape, was developed in the UK. Also, an elliptical jacket (a stress applying member provided around the clad) has been developed and put to practical use in Japan. Although a core with a deformable structure was studied, it has not been put to practical use.

In connection between such polarization-maintaining optical fibers and connection between the polarization-maintaining optical fibers and other devices, it is necessary that the mutual polarization planes be matched with high precision. For this purpose, the work of individually adjusting and connecting is performed. A pair of ferrules supporting an optical fiber to be coupled are inserted into a sleeve, opposed to each other, a light source is connected to one side, and an optical power meter is connected to the other side. The above method can be realized by using the configuration shown in JP-A-61-228404.

[0005]

As described above, an accurate index for indicating the polarization plane is provided to the ferrule of the polarization maintaining optical fiber without adjusting the alignment of the individual polarization planes. For example, based on the index, ferrule and ferrule, ferrule and light source,
If the ferrule is combined with a device having polarization characteristics, individual adjustments should not be required at all. SUMMARY OF THE INVENTION An object of the present invention is to provide a polarization-maintaining optical fiber ferrule or an index portion on a ferrule alone to which an optical fiber is attached, without performing the polarization plane alignment work in the assembled connector as in the conventional art. To provide a method of manufacturing an optical fiber ferrule assembly having an angle index indicating the polarization plane direction of an optical fiber, parts of the assembly used in the method, and an assembly jig used in the method. It is in.

[0006]

According to the present invention, there is provided a method of manufacturing an optical fiber ferrule assembly having an angle index indicating a polarization plane direction of an optical fiber according to the present invention. In the method for manufacturing a ferrule assembly, a step of preparing a polarization-maintaining optical fiber, a step of preparing an optical fiber ferrule assembly that receives and holds the optical fiber and exposes and fixes the tip end face thereof, and an angle index portion, Preparing an angle index member that is rotatable with respect to the ferrule and the angle index portion is fixed at a fixed angular position with respect to the polarization plane of the optical fiber; Fix the optical fiber ferrule assembly with one fixed In the state where the optical fiber is in an inclined state, the polarization plane direction is determined from its shape by observing the end face of the optical fiber in a magnified manner, and the angle index is relatively rotated so that the angle index becomes a constant angle with respect to the polarization plane direction. And fixing. According to a second aspect of the present invention, there is provided a method of manufacturing an optical fiber ferrule assembly according to the first aspect, wherein the optical fiber ferrule assembly is fixed to the optical fiber ferrule and a base of the ferrule. A flange body for receiving the covering portion, wherein the angle index member comprises:
It has an index index on the outer periphery and has an angle index indicating the direction of the polarization plane of the optical fiber, which is a member inserted into the ferrule from the tip of the ferrule at the center hole and rotatably coupled to the ferrule.

According to a third aspect of the present invention, there is provided a manufacturing method comprising:
The method of manufacturing an optical fiber ferrule assembly according to claim 1, wherein the angle index member is fixed to a stage of a microscope based on the index while the optical fiber ferrule is rotatably supported,
Rotating the ferrule while observing an enlarged image of the stress applying member at the tip of the optical fiber with the microscope, the index member and the ferrule when the enlarged image reaches a fixed relationship with the index of the angle index member. And a step of bonding and fixing.

According to a fourth aspect of the present invention, there is provided an optical fiber ferrule assembly manufactured by the optical fiber ferrule assembly manufacturing method according to the first aspect, wherein the angle index member has a pair of indices on its outer periphery. The ferrule has a central hole inserted into the ferrule from the tip of the ferrule and rotatably loosely fitted therein, and an adhesive receiving groove on the bottom surface side. According to a fifth aspect of the present invention, there is provided an assembling jig used in the method of manufacturing an optical fiber ferrule according to the first, second or third aspect, wherein the angle index member and the optical fiber ferrule are assembled. Are provided in such a manner as to be able to move relative to the objective lens of the microscope by temporarily supporting the angle index member in a state of being frictionally coupled. Claim 6 according to the invention
The assembling jig according to claim 5, wherein
The angle index member and the assembly shaft are configured such that an angle index portion of the assembly shaft and a protrusion of the jig are frictionally coupled.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical fiber ferrule assembly having an angle index for indicating the direction of the plane of polarization of an optical fiber according to the present invention will be described in more detail with reference to the drawings. FIG. 1 is an exploded perspective view for explaining an adjusting process of an optical fiber ferrule assembly having an angle index indicating a polarization plane direction of an optical fiber according to the present invention. FIG. 2 is a sectional view showing an embodiment of the optical fiber assembly. After removing the coating of the polarization maintaining optical fiber, the core of the optical fiber 5 is inserted into the ferrule 1 and glued and fixed. At this time, the tip of the optical fiber is located on the same plane as the end face of the ferrule or at a position slightly protruding, and the surface is made an optically smooth surface free from dirt and scratches. At this time, the angular positional relationship of the optical fiber 5 with respect to the ferrule 1 does not matter at all. The optical fiber 5 is inserted and fixed in the center hole of the ferrule 1 in a state where the coating 4 of the optical fiber is inserted and fixed in the flange body 3 having the flange 31, and the base of the flange body 3 and the ferrule 1 are also bonded with an adhesive. Keep it fixed.

FIG. 3 is a sectional view showing an embodiment of the angle index member of the above embodiment, and FIG. 4 is a bottom view of the angle index member of the above embodiment. The center hole 21 of the angle index member 2 is fitted around the outer periphery of the ferrule 1 so as to be rotatable around the center axis of the ferrule 1. Index grooves 23, 2 are provided on the outer circumference of the angle index member 2.
A recess 22 is provided on the bottom side for receiving the adhesive and fixing the angle index member 2 to the flange body 3. The angle index member 2 is temporarily fitted to the ferrule 1 to form a temporary assembly state that is integrated by friction.

[0011] As shown in FIG.
The jig 9 is attached to the arms 6 and 7 on the stage side of the microscope having
Has been fixed. Two-dimensional relative movement and rotation are possible between the jig 9 and the objective lens 10 of the microscope. The optical fiber ferrule is supported as described later, and the center of the end face of the optical fiber is set to the objective lens 10. To the focal position of the optical axis. Details of the jig 9 are shown in FIGS. FIG. 5 is a sectional view of a jig 9 used in a process of assembling an optical fiber ferrule assembly having an angle index indicating the polarization plane direction of the optical fiber according to the present invention, FIG. 6 is a bottom view of the jig, and FIG. FIG. 3 is a side view of the jig. The jig 9 has screw holes 94 and 95
As shown in FIG. 1, the ferrule 1 is fixed to the arms 6 and 7 on the stage side of the microscope with screws 8A and 8B, and the ferrule 1 is received at the center of the jig 9 in the temporarily assembled state. Also, projections 92 and 93 are provided on the bottom surface of the jig 9,
The width of the projection is a width corresponding to the index grooves 23 and 24 on the outer periphery of the angle index member 2 of the temporary assembly ferrule, and the projections engage with the grooves 23 and 24 to support the angle index member 2 by friction. Its rotation is limited.

FIG. 8 is an explanatory diagram showing an example of the field of view of a microscope. In the visual field of the microscope, the reference surface 96 of the jig 9
Alternatively, the stage is rotationally moved so that 97 coincides with the X-axis of the crosshair in the microscope visual field (FIG. 8 (I)). The stage is moved from this state, and the optical fiber 1 at the center of the jig is moved.
Adjust so that the center of 00 is closer to the origin of the crosshair. FIG. 8 (II) shows a state in which the center of the optical fiber 100 is almost close to the center of the crosshair. In this embodiment, the magnification of the microscope is set to 500 times. When the tip of the optical fiber is enlarged and appropriate illumination is performed, the cladding 10
The stress applying members 103A and 103B in No. 2 have optical characteristics different from those of the cladding, so that their contours appear. By moving the stage of the microscope with reference to this contour and rotating the ferrule of the above-mentioned temporary assembly ferrule, the arrangement of the stress applying members 103A and 103B is adjusted so as to be parallel to the Y-axis of the cross hair. When they match, an instant adhesive is injected between the flange body 3 and the flange A (angle index member) 2 into the fixing allowance 22 with a syringe, and the flange A (angle index member) 2 is fixed to the flange body 3. Then, if necessary, the grooves 92 and 9 of the flange A
The end face is polished with reference to No. 3. Using the ferrule assembly manufactured in this manner, an SC type connector, FC
Shaped connectors can be assembled. The assembling procedure is conventional with reference to the grooves 92 and 93 of the flange A.

[0013]

Since the optical fiber ferrule assembly according to the present invention is provided with an index such as a groove indicating the plane of polarization, even in the case of a connector which cannot be rotationally aligned with a screw after assembly, such as an SC connector, the ferrule can be used. It can be aligned by itself and no adjustment is required. In the case where the reflection return loss is reduced by tilting and polishing the tip of the optical fiber, it is necessary to maintain a certain relationship between the direction of tilt and the plane of polarization. In such a case, oblique polishing can be easily performed by itself with reference to the index of the ferrule assembly. (Modifications) Various modifications can be made to the embodiment described in detail above within the scope of the present invention. In the above ferrule, a microscope was used in the assembling process, and an example was shown in which an operator observed and adjusted the image of the end face of the optical fiber with eyes.However, the ferrule was fixed and the microscope image of the end face of the fiber was formed on the CCD. Then, the angle of the center line connecting the two stress applying members is specified by image processing, and the stage is automatically rotated and moved based on the positional information to automatically form the state shown in FIG. 8 (III). it can. Although an example of a groove is shown as an example of the shape of the index, a protrusion may be used as long as the index can be used as a reference for later deformation such as engraving or scoring.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view illustrating an adjusting process of an embodiment of an optical fiber ferrule assembly having an angle index indicating a polarization plane direction of an optical fiber according to the present invention.

FIG. 2 is a cross-sectional view of an embodiment of an optical fiber ferrule assembly having an angle index indicating a polarization plane direction of an optical fiber according to the present invention.

FIG. 3 is a sectional view showing an embodiment of the angle index member of the embodiment.

FIG. 4 is a bottom view of the angle index member of the embodiment.

FIG. 5 is a cross-sectional view of a jig used in a process of assembling an optical fiber ferrule assembly having an angle index indicating a polarization plane direction of an optical fiber according to the present invention.

FIG. 6 is a bottom view of the jig.

FIG. 7 is a side view of the jig.

FIG. 8 is a schematic diagram showing a microscope field of view and an enlarged end of an optical fiber for explaining the adjusting step.

FIG. 9 is a schematic view for explaining the principle of a PANDA type optical fiber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ferrule 2 Flange A (angle index member) 3 Flange body 4 Coating part of optical fiber 5 Polarization maintaining optical fiber 6, 7 Microscope stage arm 8A, 8B Jig mounting screw 9 Jig 10 Microscope objective lens 21 Flange Center hole of A 22 Glue fixing allowance (depression) of flange A 23, 24 Groove (index groove) of flange A 31 Flange 91 Center hole of jig 92, 93 Coupling projection of jig 94, 95 Screw hole of jig 96 97 Reference surface of jig 100 PANDA fiber 101 Optical fiber core 102 Optical fiber cladding 103A, 103B Optical fiber stress applying member

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shuichi Takashi 23 286, Matsuhidai, Matsudo-shi, Chiba Prefecture Inside Seiko Giken Co., Ltd. Inside

Claims (6)

[Claims] 1. A method for manufacturing a ferrule assembly of an optical fiber, comprising the steps of: preparing a polarization-maintaining optical fiber; and preparing an optical fiber ferrule assembly that receives the optical fiber, exposes the distal end surface thereof, and holds the optical fiber. Preparing an angle index member having an angle index portion, which itself is rotatable with respect to the ferrule, and wherein the angle index portion is fixed at a fixed angular position with respect to the polarization plane of the optical fiber; The optical fiber ferrule assembly in which the optical fiber is fixed to the angle index member is coupled and one of the optical fiber ferrule assemblies is fixed, and the polarization plane direction is determined from the shape by observing the distal end face of the optical fiber in an enlarged manner, The angle index is relatively rotated so that the angle index is at a constant angle with respect to the polarization plane direction. Optical fiber ferrule assembly method of manufacture comprising the angle index indicating the polarization direction of the optical fiber which is composed of a step of securing to each other by. 2. The method for manufacturing an optical fiber ferrule assembly according to claim 1, wherein the optical fiber ferrule assembly includes: an optical fiber ferrule; and a flange body fixed to a base of the ferrule and receiving a coating portion of the optical fiber. The angle index member has an index portion on the outer periphery, and has a center hole, and is a member that is inserted from the tip of the ferrule into the ferrule at the center hole and rotatably coupled to the ferrule, and has an angle index that indicates a polarization plane direction of the optical fiber. A method for manufacturing a fiber ferrule assembly. 3. The method for manufacturing an optical fiber ferrule assembly according to claim 1, wherein the angle index member is fixed to a stage of a microscope with reference to the index while the optical fiber ferrule is rotatably supported. Rotating the ferrule while observing an enlarged image of the stress applying member at the tip of the optical fiber with the microscope, when the enlarged image reaches a fixed relationship with the index of the angle index member, the index member and the A method of manufacturing an optical fiber ferrule assembly having an angle index for indicating the direction of the plane of polarization of an optical fiber, the method including a step of bonding and fixing a ferrule. 4. The angle index member, which is a component of an optical fiber ferrule assembly manufactured by the method of manufacturing an optical fiber ferrule assembly according to claim 1, has a pair of index portions on an outer periphery, and the ferrule is attached to the ferrule. A central hole inserted from the tip and rotatably loosely fitted,
Parts with adhesive receiving grooves on the bottom side. 5. The assembly jig used in the method of manufacturing an optical fiber ferrule assembly according to claim 1, wherein the angle index member and the optical fiber ferrule assembly are tentatively frictionally connected to each other. An assembly jig which supports the member and is provided so as to be relatively movable with respect to the objective lens of the microscope. 6. The assembly jig according to claim 5, wherein the angle index member and the assembly shaft are configured such that an angle index portion of the assembly shaft and a projection of the jig are frictionally coupled. Assembly jig.