JPH07117477B2 - Switchable light source switching method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical power meter in which a switchable light source and a photodetector are detachably attached to a main body, and the switching of the switchable light source and the photodetector. The present invention relates to a switchable light source switching method capable of switching the sensitivity of (1) without erroneous operation.

[Conventional technology]

When measuring the insertion loss of the line system in optical fiber installation, inspection, maintenance, etc. in the optical communication field, 1.3 μm, 1.55 μm
A light source with a wavelength of m is used. This is because the wavelength of the light source used in the communication field is 1.3 μm and 1.55 μm.
Therefore, when measuring insertion loss, etc., 1.3 μm, 1.55
It is effective to use a switchable light source including two or more wavelengths such as μm because the scale is small. Further, the light receiving element of the light detector on the light receiving side has wavelength sensitivity characteristics, and the sensitivity must be switched depending on the wavelength of the light source. Therefore, when measuring the insertion loss, it is necessary to match the wavelength of the light source with the wavelength sensitivity of the photodetector. Further description will be given below with reference to the drawings.

FIG. 4 shows a conventional wavelength switching method for a switchable light source. In this figure, 10 is a main body to which a switchable light source 20 and a photodetector 30 are detachably provided.
FIG. 5 shows the switchable light source 20 and the photodetector 30 from the main body 10.
Shows the state of having left. The switchable light source 20 is provided with a wavelength switch 21, and in this embodiment, 1.3 μm and 1.55 μm.
It is possible to switch to any of m. The photodetector 30 is provided with a sensitivity switching unit 31, which switches the sensitivity according to the wavelength in order to compensate for the variation in sensitivity due to the wavelength. Reference numeral 11 denotes a display device, which is provided with other push button switches and the like for measuring the optical power. At the time of measurement, the wavelength switch 21 of the switchable light source 20 is operated to select a desired wavelength, for example, 1.3 μm, and the sensitivity switch 31 of the photodetector 30 is switched to 1.3 μm accordingly. Then, the optical fiber LF to be measured is connected between the switchable light source 20 and the photodetector 30, the light having a wavelength of 1.3 μm is made incident from one end of the optical fiber LF to be measured, and the light passing therethrough is detected by the photodetector. Receive light at 30. The insertion loss of the measured optical fiber LF can be obtained from the difference between the intensity of the incident light and the intensity of the received light.

[Problems to be Solved by the Invention]

Such a conventional switchable light source 20 includes a wavelength switch 21
Although the wavelength is switched by, the light receiving element of the photodetector 30 has a wavelength sensitivity characteristic.Therefore, it is necessary to switch the sensitivity switch 31 that compensates the sensitivity of the photodetector 30 in response to the switching of the wavelength. However, since it takes time to operate the two switching devices 21 and 31, not only it takes time, but the wavelengths of the switchable light source 20 and the light detection unit 30 may be different due to an operation error. However, there was a drawback that the measurement was erroneous.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks and to provide a switchable light source switching method which is simple in operation and free from erroneous operation.

[Means for Solving the Problems]

In the switchable light source switching method according to the present invention, wavelength switching of the switchable light source and sensitivity switching of the photodetector are performed in conjunction with each other.

[Action]

According to the present invention, when the wavelength of the switchable light source is switched, the sensitivity of the photodetector is automatically switched at the same time.

〔Example〕

FIG. 1 is an external view of an optical power meter for explaining an embodiment of the present invention. In this figure, 15 is a wavelength / sensitivity switch that switches both wavelength selection and sensitivity compensation at once.
Others are the same as the conventional example of FIG.

FIG. 2 is a block diagram showing an example of the circuit of FIG. In these figures, 10, 11, 20, and 30 are the same as those shown in FIG. Incidentally, 12 in the main body 10 is a CPU, which controls each part according to a program. 13 is an A / D converter, 14 is an amplifier, and 15 is a wavelength / sensitivity switch.
It is configured to switch to any of 5 μm. 16,
Reference numeral 17 is a drive circuit, and 18 and 19 are changeover switches.

Next, 22 and 23 in the switchable light source 20 are light emitting diodes, which emit light of 1.3 μm and 1.55 μm, respectively. 24 is a connector, which is a member of the switchable light source 20 side 24A and the main body 1
It is configured with the member 24B on the 0 side. In addition, 32 of the photodetectors 30
Is a photodiode, and 33 and 34 are sensitivity compensation elements of 1.3 μm and 1.55 μm. Reference numeral 35 denotes a connector, which, like the connector 24, includes members 35A and 35B.

Next, the operation will be described. The switchable light source 20 and the photodetector 30 are moved in the directions of the arrows in FIG. 2 to connect the respective connectors 24 and 35, and the switchable light source 2
0 and the photodetector 30 are integrated with the main body 10. If the wavelength / sensitivity switch 15 is switched to 1.3 μm in this state, the CPU
12 detects this, and the changeover switch 1
Put 8,19 in the position shown. As a result, the output line 14a of the amplifier 14 is connected to the drive circuit 16 and the drive circuit 16a
Is activated and the light emitting diode 22 emits light. Meanwhile, the amplifier
The input line 14b of 14 is connected to the sensitivity compensation element 3 via the selector switch 19.
Since it is connected to 3, the amplification degree of the amplification section 14 becomes a value that compensates for the 1.3 μm wavelength characteristic of the photodiode 32. Thus, the output of the photodiode 32 is amplified by the amplifier 14 to a predetermined value, converted into a digital signal by the A / D converter 13, and converted into a CPU signal.
The value of the optical power input to 12 and input to the photodiode 32 is calculated and displayed on the display 11.

FIG. 3 shows another embodiment of the present invention.
In FIG. 2, the wavelength / sensitivity switch 15 is provided on the main body 10 side, but the point that it is provided on the photodetector 30 is different. In addition to this,
The wavelength / sensitivity switch 15 may be provided on the switchable light source 20 side.

〔The invention's effect〕

As described above, according to the present invention, the switching of the wavelength of the switchable light source and the switching of the sensitivity compensation of the photodetector are performed in tandem, so that the switching of the wavelength and the sensitivity compensation can be performed with one touch. Therefore, it is possible to shorten the measurement time, and it is possible to completely prevent erroneous measurement due to the wavelength mismatch between the switchable light source and the photodetector. Therefore, when the switchable light source and the photodetector are attachable to and detachable from the main body, it is possible to prevent an erroneous operation that is particularly likely to occur.

[Brief description of drawings]

FIG. 1 is a front view of an optical power meter for explaining an embodiment of the present invention, FIG. 2 is a block diagram showing a circuit of the optical power meter of FIG. 1, and FIG. 3 is another embodiment. FIG. 4 is a front view of an optical power meter for explaining, FIG. 4 is a front view of an optical power meter for explaining a switching method of a conventional switchable light source, and FIG. 5 is a switchable light source and light detection of FIG. It is a front view which shows the state which removed the container from the main body. In the figure, 10 is a main body, 11 is a display, 12 is a CPU, 13 is an A / D converter, 14 is an amplifier, 15 is a wavelength / sensitivity switch, 16 and 17 are drive circuits, and 18 and 19 are changeover switches. , 20 is a switchable light source, 22 and 23 are light emitting diodes, 24 is a connector, 30 is a photodetector, 31 is a sensitivity switcher, 33 and 34 are sensitivity compensation elements, and 35 is a connector.

Claims (1)

[Claims] 1. A switchable light source for selecting light-emitting elements of two or more waves by switching, and light detection for receiving light from the switchable light source through an object to be measured and switching sensitivity according to a wavelength to be used. And a switchable light source and a body to which the photodetector is detachably attached, in an optical power meter, the wavelength switching of the switchable light source and the switching of the sensitivity of the photodetector are interlocked. A method of switching a switchable light source, which is characterized by being performed.