JPH0634849A - Optical fiber connector - Google Patents

Abstract

PURPOSE:To provide the optical fiber connector which connects an obliquely polished ferrule or constant polarization optical fiber with small loss. CONSTITUTION:The optical fiber connector positions ferrules F in the peripheral direction by the engagement between key pins K fixed on the sides of the ferrules F and key grooves formed on the side of an adapter when the ferrules F of plugs P are connected to each other across the adapter. The plug P has the end-surface machined ferrule F exposed and fixed at the tip of a cylindrical frame H and the ring R provided with the key pin K is mounted rotatably on the frame H; and the ferrule F is connected to the ferrule for adjustment through the adapter by engaging the key pin K and key groove with each other and at the position where the ferrule F is rotated to obtain the least loss, the ring R is fixed to the frame H.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber connector.

[0002]

2. Description of the Related Art FIGS. 3A and 3B show a conventional optical fiber connector in which an end face of a ferrule is obliquely polished or obliquely PC-polished to minimize mutual connection loss through an adapter A and yet have versatility. In order to make the key pin K and the oblique polishing vertex T have an angular deviation of + 90 ° or -9
Must be 0 °. For this reason, in a connector having an end face shape of oblique polishing or PC polishing, the key pin K is fixed to the frame H, and the ferrule F to which the fiber is adhered is incorporated in this frame H, and then the end face of the ferrule F is obliquely polished to the top. The end face was processed so that the angle deviation of the key pin K from T was + 90 ° or −90 °.

FIG. 4 shows a ferrule end surface of a connector using a constant polarization optical fiber. In the case of a constant polarization optical fiber, it is necessary to match the polarization plane of the mating connector with the polarization plane of the ferrule. A frame H having a key pin K fixed thereto is attached to F, and when the constant polarization optical fiber is bonded to the ferrule F, the polarization plane and the key pin K are positioned.

FIG. 5 (a) is a schematic view showing the connection of a ferrule whose end face is obliquely polished or obliquely PC-polished, and FIG. 5 (b) is a schematic view showing the connection of a ferrule to which a polarization maintaining optical fiber is bonded. It is a figure.

However, the limit tolerance of the angle deviation when the end face of the ferrule F was obliquely polished or obliquely PC-polished was ± 5 °, but in reality, in addition to the variation within the tolerance of the polishing jig, the frame H Due to the internal clearance, the positional deviation of the key pin K in the rotational direction from the mating connector that forms the pair is too large, and it is difficult to obtain the required optical coupling with low loss.

Further, the limit tolerance of the angle deviation in the prior art when using a constant polarization optical fiber is ± 10 °, but it is very difficult to perform this positioning accurately when the fiber is bonded to the ferrule F. Then, the angular deviation of the ferrule F in the rotation direction becomes excessive when the clearance inside the frame H is combined, and it is difficult to obtain the desired optical coupling.

In order to solve the above problems, an object of the present invention is to minimize the connection loss in an optical fiber connector whose ferrule end surface is obliquely polished or PC obliquely polished, or an optical fiber connector using a constant polarization optical fiber. To provide an optical fiber connector.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is an optical fiber connector in which a pair of plugs are opposed to each other via an adapter, and a key pin fixed to the plug side. In an optical fiber connector in which the ferrule at the tip of the plug is positioned in the circumferential direction by the engagement of the key groove provided on the adapter side with the ferrule, the plug has a ferrule whose end face is previously slant-polished, slant-PC-polished, or a constant deviation. A ferrule whose end face is processed while holding a wave optical fiber is exposed and fixed from the tip of a cylindrical frame, a ring provided with a key pin is rotatably attached to the frame, and the ferrule attaches the key pin to the adapter. It is inserted by engaging with the key groove and connected to the fixed fixing ferrule for adjustment, and the key pin is engaged with the key groove. Connection loss by rotating the ferrule is an optical fiber connector in which the ring is fixed to the frame at a position a minimum state.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. 1 (a) and 1 (b) show a plug of an optical fiber connector using an obliquely polished ferrule according to an embodiment of the present invention, and FIG. 1 (a) is an external view of a plug before a key pin ring R is attached, FIG. 2B is an external view of the plug in which the key pin ring R is attached. This plug P is composed of the ferrule F, the frame H, the coupling nut N, the bushing B, the rubber hood G, and the key pin ring R whose end faces have been obliquely polished in advance. The internal clearance that is configured and affects the rotation axis direction of the ferrule F is minimized. The key pin ring R is provided with a key pin K, and its inner diameter is almost the same as that of the cylindrical frame H, and is of a size that can be rotatably mounted on this frame H.

2 (a) and 2 (b) show a method for positioning and fixing the key pin ring R mounted on the frame H described in FIG. 1. FIG. 2 (a) is an external view thereof and FIG. 2 (b). FIG. 4 is a cross-sectional view of the main part of FIG. In the figure, the plug P is in a rotatable state only by mounting the key pin ring R on the frame H. On the other hand, the plug RFP is used as a reference for adjustment, the end face of the ferrule RFF is obliquely polished, and the position of the key pin RFK on the frame H is almost accurately positioned at an angle deviation of + 90 ° from the apex T of oblique polishing. The key pin ring RFR is fixed by any means such as welding or adhesion. Although not shown in the figure, the plug RFP is fixed to the adapter A with a coupling nut.

The adapter A is the same as that which actually constitutes an optical fiber connector, and key grooves KG which engage with the key pin K of the plug P and the key pin RFK of the plug RFP are accurately provided. . Then, as shown in the same figure, the end faces of the ferrules that have been obliquely polished are brought into contact with the key pins K and RFK engaged with the key grooves KG.

In this state, the key pin K is located at a position close to an angular deviation + 90 ° from the apex T of the oblique polishing of the ferrule F, but here, light is further input from the optical fiber on one plug side and the other plug is input. While monitoring the output with the optical fiber on the side, the plug P is slightly rotated to slightly change the connection state between the ferrule F and the ferrule RFF, and the key pin ring R is moved to the frame H at the position where the connection loss is the smallest. Fix by welding, adhesion, etc.

The optical fiber connector manufactured as described above can have a limit tolerance of ± 0.5 ° between the apex of oblique polishing of the ferrule and the key pin, and the conventional limit tolerance of ± 5 °.
It was possible to realize an efficient optical coupling, which was greatly improved from.

As described above, in the optical fiber connector of the present invention, the key pin position of the manufactured plug can be easily fixed to the position where the connection loss is minimized by using the adjustment reference plug which is manufactured in advance with high precision. Therefore, according to the present invention, it is possible to easily manufacture a plug as accurate as the adjustment plug. Therefore, the optical fiber connector constructed by using this plug is inexpensive and highly accurate.

In the above embodiment, an example in which the end face of the ferrule is obliquely polished has been described. However, the present invention is not limited to this, and the oblique polishing may be oblique PC polishing, and further, the polarization-polarized light is used. It can be applied to any optical fiber adapter of the type in which the key pin on the ferrule side and the key groove on the adapter side are engaged with each other, such as one using a fiber. As a result of trial production, diagonal PC polishing was performed. Even in the case of the optical fiber connector and the optical fiber connector using the constant polarization optical fiber, the limit tolerance of the reference pin of the ferrule end face and the angle deviation of the key pin can be set to ± 0.5 °, which is greatly improved from the conventional limit tolerance. Achieving efficient optical coupling.

[0016]

As described above, in the optical fiber connector of the present invention, the key pin position on the ferrule side can be easily fixed to the position where the connection loss is minimized, so that a highly accurate optical fiber connector can be manufactured at low cost.

[Brief description of drawings]

FIG. 1A is an external view of a plug before a key pin ring R is attached, and FIG. 1B is an external view of a plug in which a key pin ring R is attached according to an embodiment of the present invention.

2 (a) is an external view showing a method of positioning and fixing a key pin ring R mounted on a frame H in one embodiment of the present invention, and FIG. 2 (b) is a cross-sectional view of an essential part of FIG. 2 (a). It is a figure.

FIG. 3 relates to a conventional optical fiber connector, in which FIG. 3 (a) shows that the end face of the ferrule is obliquely polished,
C-polished optical fiber connector An external view of the connector, and FIG. 6B is an external view of the ferrule end face direction.

FIG. 4 relates to a conventional optical fiber connector and is an external view of a ferrule end face direction to which a constant polarization optical fiber is adhered.

FIG. 5 (a) shows that the end surface is obliquely polished or obliquely P-shaped.
FIG. 3B is a schematic view showing the connection of the C-polished ferrule, and FIG. 6B is a schematic view showing the connection of the ferrule to which the polarization maintaining optical fiber is bonded.

[Explanation of symbols]

 A Adapter F, RFF Ferrule H Frame K, RFK Key Pin KG Key Groove P, RFP Plug R, RFR Key Pin Ring

Claims (1)

[Claims] 1. An optical fiber connector in which a pair of plugs are opposed to each other via an adapter, and a ferrule at the tip of the plug is formed by engagement of a key pin fixed to the plug side and a key groove provided on the adapter side. In the optical fiber connector that is positioned in the circumferential direction, the plug has a cylindrical ferrule whose end face is obliquely polished or obliquely PC-polished in advance, or a ferrule whose pre-processed end face is held by holding a polarization maintaining optical fiber. A ring, which is exposed and fixed from the tip of the frame and is provided with a key pin, is rotatably attached to the frame, and the ferrule is inserted into the adapter by engaging the key pin with the key groove, and fixed oppositely. Position where the connection loss is minimized by rotating the ferrule with the key pin engaged with the key groove, connected to the ferrule for Optical fiber connector, wherein the ring is fixed to the frame.