JPH04265907A - Optical attenuator - Google Patents

Abstract

PURPOSE:To offer an optical attenuator which is miniaturized and variable in attenuation quantity. CONSTITUTION:This optical attenuator is provided with a ferrule 1 which has an optical fiber 12 adhered and fixed inside and has a polished end surface, a slit 1a provided on a part of the intermediate part including the optical fiber 12 f the ferrule 1, an optical attenuation plate 2 which is provided with plural adjacent attenuation films differing in optical attenuation quantity and is arranged freely movably in the slit 1a so that one of the attenuation films is on the optical axis of the optical fiber 12, a housing 1 which holds the ferrule 1 and optical attenuation plate 2, and supports 4 and 5 which hold the optical attenuation plate 2 on the ferrule 1 and housing 11.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical attenuator, and more particularly to an optical attenuator used in an optical communication system.

0002

2. Description of the Related Art In optical communication systems, the amount of optical attenuation differs depending on the length of the optical transmission path, so the level of light received by a receiving device differs. Therefore, there is a need for an optical attenuator that can be implemented in the same way as a connector within the device used to adjust the level of received light to achieve an appropriate level.

An example of a conventional optical attenuator for an optical communication system is a ferrule with an optical fiber glued and fixed inside and cut into two, and an optical attenuator placed between the cut surfaces of the ferrule. The two ferrules and the light attenuation film are fixed and protected, and one end has a connector plug,
It has a housing whose other end forms a connector jack. A fixed attenuation type optical attenuator having a shape similar to an optical connector has been used for connection to an external optical fiber using a connector plug and a connector jack of a housing. Such an optical attenuator can be connected in the same way as an optical connector in the middle of an optical transmission line, and since it is small, it can be used even in a narrow mounting space.

0004

[Problems to be Solved by the Invention] However, in such conventional optical attenuators, the amount of attenuation is fixed, and in order to adjust the level of received light to the required level, several types of optical attenuators with different amounts of attenuation must be used. There was a drawback that the optical attenuator had to be prepared in advance.

[0005] An object of the present invention is to provide an optical attenuator that is compact and capable of varying the amount of attenuation.

[0006]

[Means for Solving the Problems] The optical attenuator of the present invention includes a ferrule with an optical fiber bonded and fixed therein and a polished end face, and a part of the intermediate portion of the ferrule containing the optical fiber. a slit and a plurality of attenuation films having different amounts of light attenuation are provided adjacent to each other, and are movably arranged in the slit so that one of the attenuation films is on the optical axis of the optical fiber in a steady state. The device includes a plate, a housing that holds the ferrule and the light attenuation plate, and a support that holds the light attenuation plate to the ferrule and the housing.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a perspective view of an embodiment of an optical attenuator according to the present invention. The optical attenuator shown in FIG.
a ferrule 1 in which a ferrule 2 is glued and fixed to the central axis of a cylinder, a light attenuation plate 2 that attenuates light, support parts 4 and 5 that fix the light attenuation plate 2 in a predetermined position of the ferrule 1, and a cylindrical ferrule 1. It has a housing 11 that covers and protects the connector, and has a connector plug portion 11a at one end and a connector jack portion 11b at the other end. In addition, support 4 and 5
The light attenuation plate 2 is fixed from the outside of the cylindrical housing 11.

FIG. 2 shows a ferrule 1 according to the embodiment of FIG.
FIG. 2 is an explanatory diagram of a combination of the light attenuating plate 2 and the light attenuating plate 2. FIG. In the middle of the ferrule 1, a slit 1a is provided with a depth that can cut the fiber 12 and a size slightly wider than the width of the light attenuation plate 2. The light attenuation plate 2 is formed with attenuation films 2a to 2d that attenuate light, and the attenuation films 2a to 2d are in contact with each other at the tip of the light attenuation plate 2. This light attenuation plate 2 is inserted into the ferrule 2 from the tip, but in order to position the tip, there is a hole at the bottom of the slit 1a.
c is provided. Note that the slit 1a is inclined from several degrees to several tens of degrees with respect to the optical axis to prevent reflection of light. Further, it is convenient for manufacturing that the forming process is performed after the optical fiber 12 is fixed to the ferrule 1.

FIG. 3 is a longitudinal sectional view of the ferrule 1. The ferrule 1 has a capillary 1 between it and the optical fiber 12.
b is provided. A refractive index matching agent 3 is used between the slit 1a and the light attenuation plate 2 inserted therein in order to reduce the loss of light between the light attenuation plate 2 and the optical fibers 12 on both sides thereof. Sometimes.

FIG. 4 is a detailed plan view of the light attenuation plate 2. As shown in FIG. The light attenuation plate 2 is divided into regions of attenuation films 2a, 2b, 2c and 2d, each having a different amount of light attenuation. The attenuation films 2a to 2d are, for example, films on which an attenuation material that attenuates light is deposited. Each of the damping films 2a to 2d is in contact with an adjacent damping film by a chord, and the tip thereof has a fan-like shape in which all the damping films 2a to 2d are in contact with each other. Furthermore, a protrusion 2e is provided on the arc of the fan-shaped light attenuation plate 2 for its operation.

FIG. 5 is a diagram illustrating a support assembly of the optical attenuator of the embodiment of FIG. With the housing 11 covered by the ferrule 1, the light attenuating plate 2 is inserted into the slit 1a of the ferrule 1, and the supports 4 and 5 close the light attenuating plate 2.
is held in the housing 11 and the ferrule 1. It goes without saying that the housing 11 requires a slit on the same concentric circle as the slit 1a provided in the ferrule 1.

FIG. 6 is a detailed expanded view of the support 4. As shown in FIG. The support 4 is made of an elastic material, and the light attenuation plate 2
The slit portion 4b1 is slightly narrower than the thickness of the protruding portion 2e.
4b3 and holes 4a1 to 4 in which the protrusion 2e stays during normal operation.
A4 is formed.

FIG. 7 is a sectional view taken along line A1-A2 of the embodiment shown in FIG.
Details of the positional relationship between the supports 4, 5 and the optical fiber 12 are shown. The tip of the optical attenuation plate 2 is inserted into the hole 1c of the ferrule 1, and in the current state, the attenuation film 2b blocks the optical fiber 12. The attenuation film 2b is attached to the optical fiber 1
It is located at some angle with the optical axis of No. 2.

When the optical attenuator is assembled as shown in FIG. 1 or 5, the protruding portion 2e of the optical attenuating plate 2 is moved along the slit portions 4b1 to 4b3 using the elasticity of the support 4. It can be fitted into any of the holes 4a1 to 4a4. Referring to FIG. 7, when the optical attenuation plate 2 rotates around the hole 1c within the slit 1a of the ferrule 1 due to the above-described operation, the attenuation films 2a to 2d optically connected to the optical fiber 12 change. , a variable attenuator can be constructed.

In this way, a compact connector-type optical attenuator is obtained in which the protrusion 2e of the optical attenuation plate 2 is used as a variable mechanism.

In this embodiment, an optical attenuator having a plug-jack type connector was explained.
The invention may include other jack-to-jack type connectors. Further, as long as the light attenuation plate has a plurality of attenuation films, the slit in the ferrule may be moved in parallel. For this purpose, as a structure for holding the light attenuation plate, a sliding housing, support, etc. suitable for parallel movement of the attenuation film can be used.

[0018]

As explained above, the present invention provides a light attenuation plate having a plurality of attenuation films having different attenuation amounts in the middle part of a ferrule, and the light attenuation plate is inserted into the cylindrical ferrule.
For example, rotational movement has the effect of providing a compact optical attenuator that can easily change the amount of optical attenuation.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the invention.

FIG. 2 is an explanatory diagram of a combination of the embodiment of FIG. 1;

FIG. 3 is a longitudinal cross-sectional view of the ferrule.

FIG. 4 is a detailed plan view of the light attenuation plate.

FIG. 5 is a support installation diagram of the optical attenuator of the embodiment of FIG. 1;

FIG. 6 is a detailed development diagram of the support.

FIG. 7 is a sectional view taken along line A1-A2 of the embodiment shown in FIG. 1;

[Explanation of symbols]

1 Ferrule 1a Slit 1b Capillary 1c Hole 2. Light attenuation plate 2a-2d Attenuation film 2e Protruding part 3. Refractive index matching agent 4 Support 4a1~4a4 Hole 4b1~4b3 Slit part 5 Support 11 Housing 11a Connector plug part 11b Connector jack part 12 Optical fiber

Claims (1)

[Claims] 1. A ferrule with an optical fiber bonded and fixed therein and a polished end surface; a slit provided in a part of the intermediate portion of the ferrule containing the optical fiber;
a light attenuation plate having a plurality of adjacent attenuation films having different amounts of light attenuation and movably disposed in the slit such that one of the attenuation films is on the optical axis of the optical fiber in a steady state; An optical attenuator comprising: a housing that holds a ferrule and the optical attenuation plate; and a support that holds the optical attenuation plate to the ferrule and the housing.