JPH0442805Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an optical fiber connector used, for example, in measuring the characteristics of components of an optical communication system.

(Prior Art) As a conventional optical fiber connector, there is one shown in FIG. 3, for example.

In FIG. 3, reference numeral 21 denotes an optical fiber, the optical fiber 21 is coated with an outer jacket to form an optical fiber cable 22, and the end of the optical fiber 21 is provided with a ferrule 23 for centering. installed. 24 is a holding member, and the ferrule 23 is
It is housed in the holding member 24 so as to be movable in its axial direction, and its extraction is restricted by the flange 23a and the inward flange 24a on the side of the holding member 24. Further, a coil spring 25 is compressed between the flange portion 23a and the step portion on the side of the holding member 24, so that the ferrule 23 always has a tendency to protrude from the holding member 24.

26 is a housing that becomes a coupling nut, and a screw 2 for connecting and fixing is provided on the inner periphery of the tip side of the housing.
6a is engraved. The screw 26a is screwed into an adapter having an alignment sleeve (not shown). The holding member 24 is movably housed in the housing 26, and when the housing 26 is screwed into the adapter, its stepped portion 24b engages with the inward flange 26b on the housing 26 side and moves forward toward the adapter. 27 is a fiber holder.

Then, the ferrule 23 is butted against another facing ferrule (not shown) via the matching sleeve in the adapter, and the housing 26 is screwed onto the adapter to connect the optical fiber cable 22 to the optical fiber to be measured, etc. The other end of the cable 22 is connected to a measuring device or the like via another optical fiber connector to measure the transmission characteristics of the optical fiber to be measured.

(Problems to be solved by the invention) In the conventional optical fiber connector, the ferrule 23 is movably housed in the holding member 24, and the coil spring 25 is compressed between the holding member 24 and the ferrule 23. Furthermore, since the holding member 24 was movably housed in the housing 26, when the housing 26 was screwed into the adapter, the ferrule 23 moved, causing an axis misalignment in the connection of the optical fiber, and the ferrule 23 is transmitted to the optical fiber core wire 21, mode conversion occurs in the propagation mode of light, and a problem arises in that the level of the transmitted optical power is likely to fluctuate.

In addition, since the fiber cable 22 was constructed by only covering the optical fiber core 21 with an outer sheath, it would move and bend due to external force, causing mode conversion in the light propagation mode as described above. There was a problem that level fluctuations were likely to occur in the transmitted optical power. Therefore, when conventional optical fiber connectors are used to measure the characteristics of components of optical communication systems, there is a problem in that it is difficult to perform precise measurements.

This invention was made based on the above-mentioned circumstances, and an object thereof is to provide an optical fiber connector that can prevent level fluctuations in transmitted optical power.

(Means for solving the problems) Next, the means for solving the above problems are as follows.
Embodiments will be explained with reference to drawings corresponding to embodiments.

That is, the optical fiber connector according to this invention is attached to the end of an optical fiber core wire extended from the end portion of the optical fiber cable with the outer jacket peeled off, and has a flange portion 3a on the outer periphery for centering. a ferrule 3; a fiber holder 9 fitted on the outer periphery of the jacket of the optical fiber cable; and a flange 3 of the ferrule 3 on the inner periphery of the front end.
a, a cylindrical holding member 4 whose rear end is fitted into the fiber holder 9 and through which the optical fiber core wire is inserted; A housing 6 as a coupling nut with a screw 6a for connecting and fixing formed on the inner periphery of the tip side, and a synthetic resin material having a lower thermal conductivity than the housing 6, and an outer periphery of the housing 6. A spring member 7 is provided between the holding member 4 and the housing 6 and applies an elastic force to the holding member 4 in the direction in which the ferrule 3 protrudes. It is characterized by

(Function) In the above configuration, in order to connect the above optical fiber to another optical fiber (optical fiber to be measured), the ferrule 3 is butted against the ferrule of another optical fiber cable via the matching sleeve in the adapter. , hold the grip part 8 and rotate the housing 6 to screw it into the adapter. At this time, the ferrule 3 is pressed by the ferrule of another optical fiber cable, but this pressing force is transmitted to the housing 6 via the holding member 4 and the spring member 7, and affects the optical fiber core wire. I have nothing to give. That is, this optical fiber is held by connecting and fixing the ferrule 3 fixed to the tip thereof and the fiber holder 9 fixed to the rear part through the holding member 4 between them, so that it is not exposed to the outside. It is not affected by the power of In addition, the body temperature during connection work is
There is no possibility that the optical fiber core wire will be expanded or contracted due to being blocked by the gripping portion 8.

(Example) Hereinafter, an example of this invention will be described based on FIGS. 1 and 2.

First, to explain the structure of the optical fiber connector, in FIG. 1, 1 is the optical fiber core, 2 is the outer sheath, and a centering ferrule 3 is attached to the end of the optical fiber core 1. There is. Reference numeral 4 denotes a holding member, and the ferrule 3 is tightly held by the holding member 4 at portions such as the collar portion 3a. In the illustrated example, the holding member 4 can be divided into three parts at the threaded parts 4a and 4b, and after fitting the ferrule 3 into the holding member 4 in advance, the threaded parts 4
By tightening and fixing a, the ferrule 3 is tightly held within the holding member 4 via the spacer 5. Note that by appropriately forming the shape of the holding member 4, it is also possible to tightly hold the ferrule 3 within the holding member 4 without using the spacer 5.

6 is a housing that becomes a coupling nut, and a screw 6a for connecting and fixing is provided on the inner periphery on the tip side of the housing.
is engraved. The holding member 4 is housed in the housing 6, and both 4 and 6 are movable relative to each other.The holding member 4 is held by the housing 6 by the stepped portion 6b on the housing 6 side and the collar portion 4c on the holding member 4 side. Extraction of the member 4 is restricted.

A coil spring 7, which is a spring member, is compressed between the flange 4c on the holding member 4 side and the inner wall of the rear end of the housing 6, and its elasticity causes the ferrule 3 to protrude integrally with the holding member 4. has been granted.

A ring 8 serves as a grip during connection, and is fixed to the outer periphery of the housing 6. ring 8
is made of a material with low thermal conductivity, such as phenolic resin, in order to prevent heat conduction of body temperature to the optical fiber core wire 1.

Further, the rear end portion of the holding member 4 is fitted into a fiber holder 9 that holds the outer cover portion 2. Since the fiber holder 9 may also be gripped during connection, the fiber holder 9 is
In order to prevent heat conduction of body temperature to the optical fiber core wire 1, it is made of a material with low thermal conductivity such as phenol resin.

As shown in FIG. 2, the outer jacket 2 of the optical fiber core 1 is covered with a metallic flexible pipe 11 having appropriate rigidity, and the optical fiber connector 1
0 is connected to an optical fiber cable 12 with a flexible pipe. The flexible pipe 11 is configured, for example, in a bellows shape, and has an inner diameter that does not create a gap between it and the outer sheath 2, and its end is fitted and fixed to the fiber holder 9. .

Another optical fiber connector 20 is connected to the other end of the optical fiber cable 12.

Next, the action will be explained.

In FIG. 1, when the ferrule 3 is butted against another ferrule facing through the matching sleeve in the adapter (not shown), and the ring 8 is gripped and the housing 6 is screwed into the adapter, the coil spring 7 As a result, the holding member 4 and the ferrule 3 tend to be extruded integrally, and the independent movement of the ferrule 3 is suppressed, causing the optical fiber core 1 to be misaligned with respect to other optical fiber core wires to be measured. Connects accurately without any problems.

Further, as described above, since the ferrule 3 does not move alone, fluctuations are not imparted to the optical fiber core 1 connected to it.

Furthermore, since the gripped ring 8 is made of a material with low thermal conductivity, thermal conduction of body temperature to the optical fiber core 1 is prevented.

Therefore, the prevention of misalignment between the optical fibers, the fluctuation of the optical fiber 1, and the temperature change of the optical fiber 1 all work together to achieve mode conversion, etc. of the propagation mode of the transmitted light. This eliminates the occurrence of fluctuations in the level of optical power, and furthermore, it is possible to achieve reproducibility that allows high-precision connections to be made at all times.

After the optical fiber connector 10 is connected to the optical fiber to be measured, the optical fiber cable 12 is arranged into an appropriate shape by the flexibility and rigidity of the flexible pipe 11, and the optical fiber connector 20 is not shown. Connected to measuring instruments, etc.

Then, the transmission characteristics and the like of the optical fiber to be measured are measured. During this measurement, the optical fiber cable 12
The rigidity of the flexible pipe 11 prevents deformation due to external forces such as vibrations. Therefore, during measurement, mode conversion does not occur in the propagation mode of the light transmitted through the optical fiber cable 12, and fluctuations in the optical power level are prevented.

As mentioned above, when using the optical fiber connector according to this embodiment, the optical power level fluctuation occurs by about 1/100th of a dB, whereas when using a conventional one, the optical power level fluctuates by a maximum of several dB. It is possible to suppress the level fluctuations to the following extremely small level fluctuations. Therefore, when used to measure the characteristics of the components of an optical communication system or calibrate the level of a measuring device, extremely precise measurements or calibrations can be performed.

(Effects of the invention) As explained above, according to the optical fiber connector according to the invention, the flange 3a of the centering ferrule 3 attached to the end of the optical fiber core
By fitting and fixing the fiber holder 9 fitted to the outer periphery of the outer cover portion of the rear part of the optical fiber through the cylindrical holding member 4 through which the optical fiber is inserted into the inner cavity, the above-mentioned optical fiber is fixed. is protected from external forces, and this holding member 4 is elastically held in the axial direction via a spring member 7 within a housing 6 serving as a coupling nut. 3 is transmitted to the housing 6 via the holding member 4 and the spring member 7, and is not transmitted to the optical fiber core wire.

Therefore, at the time of connection, a high-precision connection is performed without causing axis misalignment between the optical fibers, and the movement of the optical fiber to which the ferrule is attached is suppressed in the axial direction and movement in the bending direction, thereby improving transmission. This has the advantage that fluctuations in the level of optical power can be significantly prevented.

Furthermore, since a grip portion 8 made of a synthetic resin material with low thermal conductivity is provided on the outer periphery of the housing 6,
During connection work, body temperature is blocked by the grip part 8,
The optical fiber core inside the holding member 4 does not expand or contract.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view showing an embodiment of the optical fiber connector according to the invention, Fig. 2 is an external view partially cut away showing the same optical fiber connector and the optical fiber cable attached to it, and Fig. 3. FIG. 1 is a vertical cross-sectional view showing a conventional optical fiber connector. DESCRIPTION OF SYMBOLS 1... Optical fiber core wire, 2... Outer cover, 3... Ferrule, 4... Holding member, 6... Housing,
7... Coil spring (spring member), 10...
Optical fiber connector, 12... optical fiber cable.

Claims (1)

[Scope of Claim for Utility Model Registration] A centering ferrule 3 that is attached to the end of an optical fiber core extended from the end of an optical fiber cable with its outer jacket peeled off, and that has a flange 3a on the outer periphery. , a fiber holder 9 fitted onto the outer periphery of the jacket of the optical fiber cable, and a flange 3 of the ferrule 3 on the inner periphery of the front end.
a, a cylindrical holding member 4 whose rear end is fitted into the fiber holder 9 and through which the optical fiber core wire is inserted; A housing 6 as a coupling nut with a screw 6a for connecting and fixing formed on the inner periphery of the tip side, and a synthetic resin material having a lower thermal conductivity than the housing 6, and an outer periphery of the housing 6. A spring member 7 is provided between the holding member 4 and the housing 6 and applies an elastic force to the holding member 4 in the direction in which the ferrule 3 protrudes. An optical fiber connector characterized by: