JPS58120214A - Connecting method of single polarization optical fiber - Google Patents

Abstract

PURPOSE:To obtain an optimum connection state, by measuring quntities of leakage from single polarization optical fibers. CONSTITUTION:In case that a pair of single polarization optical fibers 1a and 1b are connected, their connection faces are matched to each other, and a light 4 from a light source 3 is made incident to the incidence end of the optical fiber 1a through a polarizer 2 while rotating the optical fiber 1a or 1b. This incident light is emitted from the exit end of the optical fiber 1a and is made incident to the incidence end of the optical fiber 1b. If the axis of polarization of the light incident to the optical fiber 1b coincides with that of the optical fiber 1b, this light is incident to the core of the optical fiber 1b and is not leaked to the external; but if the axis of polarization of this incident light does not coincide with that of the optical fiber, the incident light is scattered or leaked to the outside of the optical fiber 1b. Consequently, the quantity of light leaked from the optical fiber 1b is measured to discriminate the coincidence or incoincidence of the axis of polarization. Thus, optical fibers are connected after confirming the coincidence of the axis of polarizalion to obtain an opitmum connection state.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for connecting single polarized optical fibers. In connecting single polarized optical fibers, it is necessary to match the polarization directions of both fibers. In addition to aligning the end fibers with each other as in the connection in
Must be.

By the way, the method of confirming the coincidence of the polarization directions has conventionally been carried out as follows. Connecting a pair of single polarized optical fibers a% a' to be connected as shown in Figure 1. The end faces are butted together and the light from the light source is made to enter the input end of one optical fiber a. At this time, the incident light @C is transmitted through a polarizer d2i so as to match the polarization axis of the optical fiber a.

A polarizer d' whose polarization axis matches that of the fiber a' is also placed on the output end side of the other optical fiber a' to be connected, and the output light e from the optical fiber a' is connected to this polarizer d'. Transmit.

The transmitted output light e' enters the photodetector g, and its light intensity level is displayed on the meter.

During the measurement of the light intensity level, either optical fiber a or a' is rotated, and the light intensity level is determined by the polarization axis of the single polarized light incident on the input end of optical fiber a and the other optical fiber a. The maximum value is reached when the cross section of the fiber a' at the input end of the fiber a' coincides with that of the fiber a'.

Therefore, when the light intensity level reaches the maximum, an optimal connection state can be obtained by connecting both fibers a% a' by adhesion or fusion.

However, in such a method, if the other single polarization optical fiber a' is long, it is difficult to know the output of the photodetector (6) from the connection point of both fibers a1 and a'. Even if (8) could be made longer, it would be difficult due to limitations.

The present invention aims to solve the above problem by measuring the leakage light at an arbitrary position of the other optical fiber a', and this will be explained with reference to an embodiment shown in the drawings. fil a, (1) b is a pair of single polarized optical fibers to be connected, (2) is a polarizer placed on the input end side of one optical fiber 11) a, and a light source (3) This is to match the polarization axis of the light (4) from the optical fiber (11a) to that of one optical fiber (11a).

A pair of single polarization optical fibers (1) a, fil b
To connect both fibers (1) a, (1)
Butt the connection end surfaces of b and connect one of the optical fibers f.
Light source (3) while rotating il a or tl) b
The light (4) is made to enter the input end of one optical fiber (11a) via a polarizer (2).

This incident light beam exits from the output end of one optical fiber (1) a and is again input to the input end of the other optical fiber ill b.

By the way, if the polarization axis of the incident light beam to the other optical fiber (1)b matches that of the same fiber +11b, it will be incident on the core of the same fiber fllb, and will leak to the outside. Although this is rare, if they do not match, the incident light beam that enters the core will be reduced, and most of it will be incident on the cladding of the fiber +11b, and will eventually be scattered out of the fiber +11b. leaks.

Therefore, by measuring the amount of leaked light leaking from the other single polarization optical fiber (1)b, it is possible to determine whether the polarization axes match or do not match.

Therefore, by placing a photodetector on the outer periphery of the other single polarization optical fiber (1)b, preferably near the connection end of the same fiber (1)b, and reading the output with a meter, the amount of leaked light can be determined. become.

In the present invention, the other single polarization optical fiber ill b
A photodetector (4) is placed at the connection end of the detector (4).
The output from the sensor is read by a meter (5).

Then, while watching the display on the meter (5), one of the optical fibers (1) a or Fil b is rotated, so that the polarization axis of the light incident on the other optical fiber 111 b and the same fiber 111 b are rotated. When it matches that of , all the incident light is transmitted into the core of the same fiber, so that no scattered or leaked light is observed near the connection end of the same fiber fl1b.

Therefore, when the value of meter (5) becomes the minimum, it is the position where the polarization axes match, and both fibers fl) a
, fll b can be fixed by fusing or gluing them together to obtain an optimal connection state.

By the way, when observing leakage light in this way, it is necessary to remove the outer jacket etc. of the other optical fiber tllb, but since conventionally the outer jacket etc. were removed when connecting, it is necessary to remove the outer jacket etc. This does not mean that the number of additional processes will increase.

As the photodetector (4), there is used a type in which an optical fiber is inserted between the detecting portion of the detector (4) (for example, product 1tMs94A manufactured by Aki Denki Co., Ltd.).

In other words, the above-mentioned detector measures the amount of leaked light from the connection end, and the optimal connection state is determined based on the amount of leaked light.If the amount of leaked light is small, the light is transmitted to the core of the other optical fiber (1) b. Since it is incident inside,
This means that the polarization axis of the incident light coincides with that of the same fiber
This indicates that the polarization axis of the incident light does not match that of the fiber (1) b. Since it is possible to obtain the optimal connection state by measuring the amount of leakage from a single polarized optical fiber, there is no need to measure the light level at the output end of the 92 Eyeper as in the conventional example, and the optical fiber Therefore, if the optical fiber is long, there is no difficulty in determining the output of the photodetector if a position close to the connection point is selected as the measurement point.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional connection method, and FIG. 2 is an explanatory diagram of a connection method according to the present invention. tl) a, (Il b...Single polarization optical fiber patent applicant representative Patent attorney Makoto Ito

Claims (2)

[Claims] (1) When connecting single polarized optical fibers, single polarized light is input from one single polarized optical fiber to the other single polarized optical fiber, and the amount of leaked light leaks from the other single polarized optical fiber. 1. A method for connecting single-polarized optical fibers, characterized in that the connection is performed after confirming the coincidence of the polarization axes of the single-polarized optical fibers to be connected by measuring . (2) A method for connecting single polarized optical fibers according to claim 1, characterized in that the amount of leaked light leaking from the connecting end of the other single polarized optical fiber is measured.