JPH05134141A - Manufacture of ceramic optical connector ferrule and ceramic optical connector ferrule manufactured thereby - Google Patents

Abstract

PURPOSE:To provide an effective manufacturing method of a ceramic optical connector ferrule of high accuracy. CONSTITUTION:An optical fiber inserting hole 2 and an optical fiber core wire inserting hole 4 are communicated to each other on the axis, and are thus drilled, while a predetermined grinding process is carried out on a sleeve part 3 of a heat-sintered mold 1 of ceramic powder, which is formed by forming a step difference by reducing the diameter of a flange part 5, on the outer periphery of the boundary between the sleeve part 3 on which the optical fiber inserting hole 2 is drilled and the flange part 5 on which the optical fiber core wire inserting hole 4 is drilled. Since a part that is in close proximity to the sleeve part 3 of the flange part 5 is recessed, grinding process of the sleeve part 3 is carried out accurately and effectively without being interrupted by the flange part 5, and the sleeve to be abutted can be inserted into a fitting cylinder accurately and easily. Since the entire body of a ferrule is formed out of ceramic of low coefficient of thermal expansion, difference in the size due to varying temperature is limited to a small level, and optical connection is achieved well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently manufacturing a ceramic optical connector ferrule having excellent dimensional accuracy and a ceramic optical connector ferrule manufactured by the manufacturing method.

[0002]

2. Description of the Related Art Conventionally, in order to directly connect optical fiber core wires to each other, as shown in FIG. 2, an optical fiber through hole 2 and an optical fiber core wire through hole 4 are provided so as to communicate with each other at an axis. The connector ferrule 6 is attached to the end portion of the optical fiber core wire 8 to be connected with the optical fiber 7 exposed for a predetermined length, the extra optical fiber protruding from the tip of the ferrule 6 is cut, and the cut portion is mirror-finished. This optical fiber 7
The exposed front end surface of the optical fiber was attached to the exposed front end surface of the optical fiber to which the other ferrule to be connected was abutted. By the way, a metal ferrule has been conventionally used for such an optical connector ferrule 6, but the sleeve portion 3 into which the optical fiber 7 is inserted has a slight misalignment of the axial center due to thermal expansion or the like. However, there is a problem in that the metal ferrule having a large coefficient of thermal expansion cannot accurately transmit light to each other because the amount of light to be transmitted is greatly influenced. Under these circumstances, a composite type optical connector ferrule made of a ceramic material and a metal material has been developed. That is, in this composite ferrule, as shown in FIG. 3, a ceramic material having a small coefficient of thermal expansion is used for the sleeve portion 3 into which the optical fiber is inserted, and the flange portion 5 through which the optical fiber core wire is inserted has workability. A metal material having good properties is used, and both are joined by press fitting.

[0003]

However, since the sleeve portion 3 and the flange portion 5 are joined by press fitting to the composite ferrule 9, the reliability of the joint portion is low.
There is a problem that the press-fitting joint portion of the sleeve portion 3 and the flange portion 5 requires high dimensional accuracy, resulting in high processing cost, and the sleeve portion 3 and the flange portion 5 have different thermal expansion coefficients, so that the optical fiber is easily deteriorated. .

[0004]

SUMMARY OF THE INVENTION The present invention has been made as a result of intensive studies in view of such a situation, and the purpose thereof is to make a ceramic material of high precision, high reliability, good workability and low cost. It is to provide an optical connector ferrule. That is, the invention of claim 1 is such that the optical fiber insertion hole and the optical fiber core wire insertion hole are made to communicate with each other at the axial center, and the sleeve portion and the optical fiber core wire insertion hole which are provided with the optical fiber insertion hole are provided. The ceramic sleeve is characterized in that the sleeve portion of the heat-sintered compact of ceramic powder formed by reducing the diameter of the flange portion at the outer periphery of the flange portion having the hole It is a method of manufacturing an optical connector ferrule.

In the method of the present invention, the reason why the optical connector ferrule is integrally made of the ceramic material is that the ceramic material has a low coefficient of thermal expansion, so that the optical coupling between the optical fibers is always performed accurately without being affected by the temperature change. In addition, it is possible to avoid the problems of lack of reliability and high cost due to the joint portion of the composite ferrule. The reason for forming a step by reducing the diameter of the flange portion on the outer periphery of the boundary portion between the sleeve portion and the flange portion of the heat-sintered molded body used in the method of the present invention is to perform the grinding of the sleeve portion accurately and efficiently, This is because if both of them are formed flush with each other, a convex portion remains on the flange portion after the sleeve portion is ground, which hinders insertion of the sleeve portion to be brought into contact with the fitting cylinder.
In the method of the present invention, the ceramics used as the raw material of the optical connector ferrule include ZrO ₂ , Al ₂ O ₃ , SiC,
Any ceramic material such as SiN and BN is used. Among them, ZrO ₂ is preferable because the thermal shock resistance is improved and the yield during heating and sintering is improved by adding a rare earth element. . In the method of the present invention, the reason why the sleeve portion is ground is that the sleeve portion is accurately finished to a predetermined size, and the outer peripheral surface of the sleeve portion and the inner surface of the optical fiber insertion hole are smoothed. Any grinding method such as turning, milling, or honing can be applied to this grinding.

According to a second aspect of the present invention, there is provided a ceramic optical connector ferrule produced by the method according to the first aspect, wherein the sleeve portion of the ferrule is finished by grinding with high dimensional accuracy, and the material is made of a material. Since it is made of ceramics having a small coefficient of thermal expansion, optical coupling between the optical fibers can be performed well. Further, since the flange portion adjacent to the sleeve portion is recessed from the sleeve portion, insertion of the abutting sleeve into the fitting cylinder can be performed accurately and easily.

[0007]

In the method of the present invention, the optical fiber insertion hole and the optical fiber core wire insertion hole are made to communicate with each other in the axial center, and the sleeve portion and the optical fiber core wire insertion hole are provided with the optical fiber insertion hole. Since the sleeve portion of the heat-sintered compact of ceramic powder formed by reducing the diameter of the flange portion at the outer periphery of the boundary portion of the punched flange portion is stepped, the sleeve portions are adjacent to each other. Only the sleeve portion can be ground accurately and efficiently without being disturbed by the flange portion. Further, the sleeve portion to be brought into contact can be inserted into the fitting cylinder accurately and easily. Further, in the obtained ceramic optical connector ferrule, since the entire ferrule is made of a ceramic material having a low coefficient of thermal expansion, the dimensional deviation due to temperature is small and the optical coupling is performed accurately.

[0008]

EXAMPLES The present invention will be described in detail below with reference to examples. ZrO ₂ powder was compacted into a predetermined shape, and the compacted body was subjected to heat treatment at 1200 ° C. for 50 hours to obtain a heat-sintered compact 1 having the shape shown in FIG. The heat-sintered molded body 1 is composed of a sleeve portion 3 having a circular cross section with an optical fiber insertion hole 2 formed in the axial center thereof, and a flange portion 5 having an optical fiber core wire insertion hole 4 formed therein. The diameter of the flange portion 5 is reduced on the outer periphery of the boundary portion of the flange portion 5 to form a step. The heat-sintered compact 1 was naturally low in dimensional accuracy and rough in surface roughness. Therefore, the outer periphery of the sleeve portion 3 of the heat-sintered body 1 which requires high dimensional accuracy is turned by a lathe to a predetermined dimension by turning with a cutting tool, and the inner surface of the optical fiber insertion hole 2 is drilled by a drilling machine. The ceramic optical connector ferrule was manufactured by smoothing. In the above-mentioned turning, since the portion of the flange portion 5 adjacent to the sleeve portion 3 is recessed, the movement of the cutting tool is not obstructed by the flange portion 5, and only the sleeve portion 3 can be ground accurately and efficiently. The ceramic optical connector ferrule manufactured in this manner was attached to the optical fiber core wire, and after the end face was polished, the sleeve portion was inserted into the fitting cylinder and the optical axes were optically coupled with each other. This ferrule was made of a ceramic and had a low coefficient of thermal expansion throughout, and good optical transmission was stable over a long period of time.

[0009]

As described above, according to the method of the present invention, a highly accurate ceramic optical connector ferrule can be efficiently manufactured, and the obtained ceramic optical connector ferrule can be accurately inserted into the fitting tube of the sleeve portion. It is also easy to make and has a significant industrial effect.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an example of a heat-sintered molded body of ceramic powder used in the method of the present invention.

FIG. 2 is a vertical cross-sectional view of a conventional metal optical connector ferrule.

FIG. 3 is a vertical sectional view of a conventional composite type optical connector ferrule.

[Explanation of symbols]

 1 Heat-sintered compact of ceramic powder 2 Optical fiber insertion hole 3 Sleeve part 4 Optical fiber core wire insertion hole 5 Flange part 6 Optical connector ferrule 7 Optical fiber 8 Optical fiber core wire 9 Composite type optical connector ferrule

Claims (2)

[Claims] 1. An optical fiber insertion hole and an optical fiber core wire insertion hole are provided in an axial center so as to communicate with each other, and a sleeve portion having the optical fiber insertion hole and an optical fiber core wire insertion hole are formed. A ceramic optical connector ferrule, characterized in that the sleeve portion of the heat-sintered compact of ceramic powder formed by reducing the diameter of the flange portion on the outer periphery of the boundary portion of the flange portion is stepped. Production method. 2. A ceramics optical connector ferrule manufactured by the manufacturing method according to claim 1.