JP2000180664A - Optical connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical connector having good optical characteristics in connecting, in a physical contact-type optical connector in which a graded index-type optical fiber is mounted. SOLUTION: In an optical connector, a graded index-type optical fiber 2 is inserted in and fixed to an approximately square ferrule 1 having a hole for fitting a positioning pin, and the connector connecting end surface is so formed that the end surface of the optical fiber 2 may project from the ferrule end surface 1b by few μm. When the ferrule end surface is polished in order to obtain the connector connecting end surface, a flat surface 2d having the width D larger than the diameter (d) of a core 2b of the optical fiber 2 is formed on the connecting end surface 2a of the optical fiber 2. When the optical fibers are mated, flat surfaces are brought into contact with each other, and the whole surface of the core can be reliably brought into contact with it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical connector of a so-called MT-type optical connector of a pin-fitting alignment type, and more particularly, to a connector end face of a physical contact using a graded index type optical fiber. Optical connector with.

[0002]

2. Description of the Related Art FIG. 1 is a view common to a conventional example and the present invention. As shown in FIG. 1, it is generally provided with a hole (guide pin hole) 1a for fitting an alignment pin (guide pin). An optical connector 3 in which an optical fiber 2 is inserted and fixed in a square ferrule 1 is used for an F12 type multi-core optical fiber connector of JIS C 5981, and is generally known as an MT optical connector. Reference numeral 4 denotes an optical fiber ribbon, and reference numeral 5 denotes a resin boot for protection.

An optical connector in which this type of MT optical connector is mounted on a housing and the connector can be connected by a one-touch operation of push-on and pull-off is a so-called MPO optical connector (F13 type multi-core optical connector of JIS C 5982). Fiber connectors), but this type of MPO
In general, in an optical connector, a so-called physical contact connection in which an optical fiber end face is directly contacted without using a refractive index matching agent on a connector joint end face is performed.

In order to form the end face of the physical contact, the end face of the ferrule is polished.
As shown in FIG. 4, the optical fiber end face 2a is polished so as to protrude from the ferrule end face 1b by about several μm (the dimension h in FIG. 4 is several μm). 2b is the core of the optical fiber 2, 2c
Denotes a cladding of the optical fiber 2. The polishing that projects the optical fiber end face 2a by several μm from the ferrule face 1b in this manner can be performed by special polishing that focuses on the difference between the hardness of the optical fiber 2 that is glass and the hardness of the ferrule 1 that uses epoxy resin or the like. It is.

[0005]

When this type of optical connector (MT optical connector) 3 is projected and polished,
In the case of an optical connector to which an SM optical fiber (single mode optical fiber) is attached, good optical characteristics are obtained, whereas a GI optical fiber (graded index type optical fiber) which is a multimode optical fiber is attached. In the case of an optical connector, the optical characteristics are poor. This is because, when the core diameter is as small as 10 μm such as SM optical fiber, when the optical fibers are brought into contact with each other, the core portions are sufficiently contacted with each other. Since the diameter is as large as 50 μm, the cores are brought into contact with each other only at a part of each other.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and an object of the present invention is to provide an MT optical connector to which a graded index type optical fiber is attached and which can obtain good optical characteristics. With the goal.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is to insert a graded index type optical fiber into a generally rectangular ferrule having a hole into which a positioning pin is fitted, and to fix the ferrule into a connector. An end face, an optical connector formed in a manner that the end face of the optical fiber protrudes from the end face of the ferrule, the joining end face of the optical fiber,
A flat surface having a width larger than the core diameter of the optical fiber is formed.

[0008] A second aspect of the present invention is characterized in that the flat surface has a width which is at least 25% larger than the core diameter of the optical fiber.

[0009]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. The optical connector of the embodiment is
The optical connector 3 of FIG. 1 described above, wherein the optical fiber 2 is inserted through and fixed to a generally rectangular ferrule 1 having a hole (guide pin hole) 1a into which an alignment pin (guide pin) is fitted. It is used in an F12 type multi-core optical fiber connector of JIS C 5981, and is generally known as an MT optical connector. 4 is an optical fiber ribbon. The optical fiber 2 is the tip itself of the optical fiber (bare fiber) of the optical fiber ribbon 4 or a separately accommodated and fixed short optical fiber connected to the optical fiber of the optical fiber ribbon 4. Is either. Reference numeral 5 denotes a resin boot for protection.

In the present invention, as shown in FIG. 3, the diameter d of the core 2b of the optical fiber 2 is attached to the joint end face 2a of the optical fiber 2.
A flat surface 2d having a larger width D is formed. Although the core diameter of the GI optical fiber is 50 μm, it is preferable to form a flat surface having a width of 25% or more of the core diameter, that is, 62.5 μm or more. 2c is clad, 1 is ferrule, 1b
Is a ferrule end face. In the case of a single-core optical connector, a circular flat surface having a diameter larger than the diameter of the core 2b is used.

According to the optical connector 3 in which the flat surface 2d is formed on the joint end surface of the optical fiber 2 as described above, since the width of the flat surface 2d is larger than the diameter d of the core 2b of the optical fiber 2, When the three optical fibers 3 are brought into contact with each other, the surfaces of the optical fibers 3 are graded index type and the diameter of the core 3b is 50 μm.
, The entire surface of the core 2b can be reliably brought into contact. Thereby, physical contact connection of the optical connector 3 becomes easy.

The optical connector 3 of the present invention is suitable for use as an optical connector of an MPO optical connector 10 as shown in FIG. The MPO optical connector 10 includes an optical connector portion 3A having the same structure as the above-described optical connector 3, a housing 11 for accommodating the optical connector portion 3A so as to be movable back and forth (left and right directions in FIG. 2), and an optical connector portion 3A. A spring 12 for pressing, a coupling 13 having a substantially rectangular tubular shape provided on the outer periphery of the housing 11, a spring 14 for pressing the coupling 13, a rear housing 15 attached to a rear portion of the housing 11 by an engagement claw 15 a, a ferrule 1.
And a pin clamp 17 for clamping the positioning pin 16 passed through the hole 1a. With this configuration,
Push-on / pull-off one-touch operation connector connection becomes possible.

Although the above embodiment has been described as a multi-core optical connector, it is naturally applicable to a single-core optical connector. Further, application to a large-diameter optical fiber other than the above embodiment is also possible.

[0014]

According to the optical connector of the present invention, a flat surface larger than the core diameter of the optical fiber is formed on the joint end face of the optical fiber housed and fixed in the ferrule. Contact between each other,
Therefore, even if the core diameter of this graded index type optical fiber is as large as 50 μm, for example, it is 6 μm.
When the thickness is 2.5 μm or more, the entire surface of the core can be reliably brought into contact. Thereby, physical contact connection of the optical connector 3 becomes easy.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of an optical connector to which the present invention is applied.

FIG. 2 is a plan view showing a main part of a so-called MPO optical connector using the optical connector (so-called MT optical connector) shown in FIG. 1 in a horizontal section, showing an application example of the optical connector of the present invention.

FIG. 3 is an enlarged cross-sectional view (corresponding to the cross-sectional view taken along line AA in FIG. 1) of an end face portion of the optical fiber in the optical connector of the present invention.

FIG. 4 is an enlarged cross-sectional view (corresponding to an AA cross-sectional view in FIG. 1) of an end face portion of an optical fiber in a conventional optical connector.

[Explanation of symbols]

 Reference Signs List 1 ferrule 1a hole (guide pin hole) 1b ferrule end face 2 optical fiber (bare fiber) 2a joint end face of optical fiber 2b core 2c clad 3 optical connector 3A optical connector section of MPO optical connector 4 optical fiber ribbon 10 MPO optical connector 11 Housing 12 Spring 13 Coupling 16 Guide Pin

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Toru Arikawa 1440, Mukurosaki, Sakura City, Chiba Prefecture Inside Fujikura Sakura Factory Co., Ltd. Terms (reference) 2H036 QA02 QA21 QA49

Claims (2)

[Claims] An optical fiber of a graded index type is inserted into and fixed to a generally rectangular ferrule having a hole into which a positioning pin is fitted, and the connector joint end face is formed such that the end face of the optical fiber protrudes from the ferrule end face. The optical connector according to claim 1, wherein a flat surface having a width larger than a core diameter of the optical fiber is formed on a joint end surface of the optical fiber. 2. The optical connector according to claim 1, wherein the width of the flat surface is at least 25% larger than the core diameter of the optical fiber.