JPS5815056B2 - Optical fiber splice loss measurement method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for measuring splice loss of optical fibers.

Conventional methods for measuring splice loss of optical fibers have been carried out using configurations as shown in FIGS. 1 to 3.

Each measurement method will be explained below with reference to the drawings.

The method shown in FIG. 1 is as shown in FIG.
Measurement is performed by the detector 3 at the position where the optical fibers are connected.

Next, connect the optical fibers and fibers together as shown in Figure 1.

The intensity of the emitted propagating light from the optical fiber 4 connected to the optical fiber 2 is measured by the detector 5.

Assuming that the transmission loss of the optical fiber 4 is measured in advance, the splice loss of the splice 6 is measured from the measured values by the detectors 3 and 5.

When using this method to measure the splice loss of an actually laid optical fiber, the detectors 3 and 5 are installed at different locations, so there is a drawback that it is difficult to calibrate the two detectors.

Also, to know the splice loss of optical fiber at the location where it is connected,
It is necessary to communicate the values measured in Detection 5 via a communication line, etc.

Furthermore, there is a drawback that the transmission loss of the optical fiber 4 must be measured.

The method shown in FIG. 2 utilizes the fact that light from the light source 1, in this case a pulsed light source (for example, a pulsed semiconductor laser), is reflected at the connection part 6, and the detection/display part 1
This method measures the splice loss of optical fibers.

In this method, the measurement value of the splice loss of the optical fiber is not accurate, and in addition, in order to know the splice loss of the optical fiber at the location where it is spliced, it is necessary to communicate from the location of the light source using a communication line or the like.

The method shown in FIG. 3 covers the connecting part 6 and its surroundings with an integrating sphere 8 (a sphere whose inner wall is a perfectly diffuse reflective surface with uniform reflectance), and detects the scattered light with a sensor 8.・Measure with the display unit body 10 (HotSpl 1ces of
0ptical Wave Guide Fibers
.

1976, 3, vol, 15, A3, A-p
(See plied 0ptics).

Although this method has the advantage of being able to determine the splice loss of the optical fiber only from the splicing location, it has the drawback of using the integrating sphere 8 and lacks workability.

The present invention is characterized by measuring the scattered light in the cross-sectional direction of the optical fiber from near the splicing part, and its purpose is to accurately measure the splice loss of the optical fiber at the splicing location, and to use an integrating sphere. The objective is to perform measurements with good workability without using

The present invention will be explained in detail below with reference to the drawings.

FIG. 4 is a diagram showing an embodiment of the present invention.

When light is input into the optical fiber 2 by the light source 1, as shown in FIG.
The intensity of the propagating light is measured by the detector 3 as shown in FIG.

After the connection is made, the intensity of the scattered light in the cross-sectional direction of the optical fibers from the connection part 6 of the connected optical fibers 2 and 4 is determined by the fourth
Measure as shown in the figure.

That is, while keeping the distance between the detection mechanism (hereinafter referred to as sensor) 12 of the detection/calculation section 11 and the optical fibers 2 and 4 and the connection section 6 constant, the sensor 12 is moved along the axis of the optical fiber (scanning). Measure the intensity of scattered light.

Instead of moving the sensor here, it is also possible to fix the sensor and move the optical fibers 2, 4 and the connection part 6.

FIG. 5 shows an example in which the intensity of scattered light from the vicinity of a connection point of an optical fiber with a connection loss of 0.07 dB was measured by the method of moving the sensor.

This is the value obtained by accumulating and measuring the intensity of scattered light along the axis of the optical fiber by moving the sensor or the optical fiber and the connection part, that is, the value of the area of the diagonal line in FIG.

P, and the intensity Pg of the propagating light measured by the detector 3
From this, the splice loss Ls can be measured using equation (1).

Here, LS: Optical fiber connection loss (dB) Pr: Intensity of scattered light (W) Pg: Intensity of propagated light (W) K: Distance between optical fiber and sensor 1 Size of light-receiving surface of sensor and sensor It is also possible to measure the intensity of the scattered light by fixing the sensor near the connecting portion 6 without moving the sensor, and also fixing the optical fiber and the connecting portion.

In this case as well, the splice loss of the optical fiber can be calculated using equation (1).

However, the values of Pr and K are different from those in the method using scanning described above.

In the method of measuring the intensity of scattered light by fixing the sensor, the optical fiber, and the connecting part, Pr is not the cumulative value of the intensity of scattered light but the intensity of scattered light at a fixed point.

In addition, both the method of moving the optical fiber or the sensor and the method of fixing both for measurement make it easier to calculate the splice loss of the optical fiber and speed up the measurement work.
It is also effective to use a detection/calculation section in which the display section has a logical calculation mechanism such as a calculation mechanism and a storage mechanism.

As explained above, the optical fiber splice loss measurement method according to the present invention measures the optical fiber splice loss by measuring the intensity of scattered light in the cross-sectional direction of the optical fiber from near the splice. The accuracy of the optical fiber splice loss value is high, the splice loss value of the optical fiber can be known at the location where it is connected, and the measurement device can be configured easily and compactly, and it has excellent workability and portability. There is an advantage of being there.

[Brief explanation of drawings]

Figures 1, 2, and 3 are explanatory diagrams of conventional optical fiber splice loss measurement methods, Figure 4 is an embodiment of the present invention, and Figure 5 is scattered light in the cross-sectional direction of the optical fiber. FIG. 3 is a diagram showing an example of measurement. 1...Light source, 2...Optical fiber, 3.
...Detector, 4...Optical fiber, 5...
...Detector, 6...Connection part, 7...
・Detection/display section, 8... Integrating sphere, 9...
・Sensor, 10...Detection/display unit main body, 11・
...detection/calculation section, 12...detection mechanism (
sensor).

Claims (1)

[Claims] 1. After measuring the intensity Pg of the propagating light that has propagated through the optical fibers with a detector, the optical fibers are connected, and a detection display with a sensor detects the intensity P of scattered light in the cross-sectional direction of the optical fibers from near the connection point. The splice loss of the optical fiber is determined by Ls, where K is a constant related to the distance between the optical fiber and the sensor, the size of the sensor's light-receiving surface, and the moving distance of the sensor. p-!-
) A method for measuring the splice loss of an optical fiber, characterized in that the splice loss is determined from the formula 8.