JPS62255906A - Optical fiber connector - Google Patents

Abstract

PURPOSE:To prevent a part of light transmitted from a fiber in ferrule, a plug, or the like from leaking by forming constituting members with a black ceramic material with less light reflection and high intensity. CONSTITUTION:An optical fiber (f) is inserted to a through hole H piercing a ferrule F press-fitted to a plug P. This plug is formed with black ceramics which less reflects the light and has a high strength. A part of the light transmitted from the fiber (f) in the ferrule F, the plug P, a connection ring, or the like is prevented from leaking to improve the reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a connector for connecting optical fibers used in optical signal transmission paths in optical communications and the like.

(Prior art) A conventionally used connector uses a cylindrical ferrule F made of an alumina ceramic body with a small hole 11 through which an optical fiber F is inserted, as shown in the exploded view of Fig. 4. The ferrule F further includes metal, synthetic resin,
A plug P made of glass, ceramic, etc. is press-fitted and the plug P is fixed to a metal fitting K, or a plug member B in which a ferrule and a plug are integrally formed of ceramic or the like as shown in Fig. 3 is used as a metal fitting. The tip end surface of an optical fiber (not shown) is fixed in the hole 11 of a plug fixed to K by adhesive, brazing, press-fitting, etc., or the plug member B is fixed to a tubular holder D as shown in FIG. There is a structure in which the ferrule F and plug B are polished so that they are flush with the tip surfaces of the plug B. In this way, with the optical fiber inserted and fixed into the plug P (plug member B), the fourth
As shown in the figure, connect the two plugs P and P with the ring S
By inserting the plugs into the plugs V and P, and by bringing the end surfaces of the optical fibers into substantial contact with each other at the centers of the ends of the plugs v and P, light is transmitted from one optical fiber to the other.

[Problem that the invention seeks to solve]

However, the above ferrule F and the integrated plug member B
are made of alumina ceramics, metals, synthetic resins, glass, etc., but ceramics are made of other metals,
Although it has the characteristics of a low coefficient of thermal expansion, high precision, and high durability compared to those made of synthetic resin, alumina ceramic as a ceramic material generally has a milky white color, so it may cause leakage at the connection surface of the optical fiber. Light is reflected from the ferrule, the tip surface of the plug member, etc., and each reflected light causes disturbances in the transmitted optical signal, resulting in noise and damage to the LD.
There was a risk of damaging light emitting elements such as laser diodes (laser diodes) and light emitted diodes (LEDs). In addition, the most commonly used alumina ceramic ferrules, plugs, connection rings, etc. have relatively low mechanical strength and are susceptible to cracking and chipping during attachment/detachment operations, resulting in poor reliability.

[Specific measures to solve the problem] In order to solve the above problem, we changed the component parts such as ferrules, plugs, and connection rings where there is a possibility that some of the light transmitted from the fiber might leak out to reflect light. It is characterized by being made of a black ceramic material that has low oxidation and high strength.

〔Example〕

Examples of the present invention will be described in detail below.

In the optical fiber plug according to the present invention, as shown in FIG. 1, an optical fiber is inserted into a through hole 11 formed in a ferrule F that is press-fitted into a plug P. In addition, the connector may be constituted by a ferrule-plug integrated optical fiber fixing member E as shown in FIGS. 2 and 3.

Incidentally, a ceramic material is used as the constituent material of the ferrule F and the optical fiber fixing member E, and various ceramics such as zirconia, alumina, silicon carbide, and silicon nitride are used as the ceramic material.

Next, Table 1 lists the coloration of each of these ceramic materials, and the light reflectance and physical property values on the surface based on the coloration.

Among the ceramic materials shown in Table 1, the light reflectance (χ) of black zirconia, silicon carbide, and silicon nitride, which exhibit a blackish-gray or black color, is all very small at 20% or less. Therefore, if the ferrules and fixing members that fix the optical fiber are made of such blackish-gray or black ceramic material, most of the light that leaks from the optical fiber connection will be absorbed and will not be reflected. Does not cause refraction. The conditions for measuring the light reflectance on each ceramic surface shown in Table 1 above are: light wavelength λ, 1300 mm incident θ, 5'', slit width 61NI11, response time 2 seconds, and surface roughness R.
This is a value determined as a relative reflectance to the reflectance of an MgO white plate under the same conditions of aO,l μm or less.

Furthermore, the black zirconia ceramic has a higher bending strength than other silicon carbide and silicon nitride ceramics, and as a result has a high toughness and resistance to cracking during connection and disconnection operations required for optical fiber connectors. There were no occurrences of chipping or the like. Therefore, in terms of strength, black zirconia ceramic is the most suitable material for the ferrule, the fixing member, and the connecting ring.

The black zirconia ceramic material is produced by adding a sintering aid such as yttria or ceria to ZrO2, molding it, and firing it, then firing the resulting white zirconia ceramic material again in a reducing atmosphere, or by removing the carbon component during refiring. By impregnating it, a black zirconia ceramic can be obtained. Alternatively, a similar result can be obtained by adding black pigment.

〔Effect of the invention〕

As described above, according to the present invention, the ferrule, fixing member, connecting ring, etc. that constitute the connecting part of the optical fiber are made of black zirconia, which has a high light absorption rate, a low reflectance, and a high bending strength (toughness strength). Since it is made of ceramic material, the reflection of light at the optical fiber connection part is extremely small, resulting in improved connection stability, less damage to the light emitting element due to reflected return light, and less noise caused by disturbance of the optical signal. It is possible to provide an optical fiber connector with stable characteristics, high reliability, and long life.

[Brief explanation of drawings]

1 to 3 are central vertical cross-sectional views of the components of an optical fiber connector according to an embodiment of the present invention. FIG. 4 is an exploded central longitudinal sectional view of each component of a conventional optical fiber connector. r: Optical fiber P nib lug F: Ferrule S: Connection ring E: Fixing member K: Metal fitting Applicant Kyocera Co., Ltd. Civility 1 Figure 2 Figure 4

Claims (2)

[Claims] (1) An optical fiber connector for connecting optical fibers, characterized in that a ferrule having a small hole through which the optical fiber is inserted and held, and a plug holding the ferrule are made of black ceramic. (2) The optical fiber connector according to claim 1, wherein the black ceramic is a ceramic made of one or more of zirconia, alumina, silicon carbide, silicon nitride, and the like.