JP2906858B2 - Optical fiber amplifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber amplifier, and more particularly to an optical fiber amplifier for detecting disconnection of an optical connector on an output side.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional optical fiber amplifier has an optical input signal terminal 1. An optical multiplexer 2 and an isolator 3 for wavelength-combining the input signal light and a pump laser diode 18 for forward pumping, an erbium-doped fiber 4 for optically amplifying the wavelength-combined light, An optical multiplexer 5 and an isolator 6 for wavelength-synthesizing the output of the fiber 4 and a pump laser diode for backward pumping; a long-wavelength bandpass filter 7 for outputting only signal light without outputting light of the pump laser diode 18; An optical splitter 9 for splitting the optical output, a photodiode 11 for splitting the optical output in the same direction as the optical output and converting the same to an electric signal, and laser driving circuits 17 and 19 using the signal converted to the electric signal.
, An automatic output power control circuit (APC circuit) 13 for controlling the optical output to be constant, a photodiode 10 for branching in the opposite direction to the optical output signal and converting this into an electrical signal, And a laser drive circuit 17 and 19 for outputting a signal when a certain level is reached, and turning off the optical output using the output of the detector.

[0003]

In this conventional optical fiber amplifier, when detecting the disconnection of the optical connector, the amplified signal is inputted to the optical splitter 22 as shown in FIG. Is output from 23 to the optical output signal terminal 20. Also, an optical signal much lower than the output of 23 is output from 24. In this case, when the optical output signal terminal 20 of the output 23 is connected to the optical connector, the output of the output 23 is output through the optical connector as it is, but when the optical connector is not connected, the optical signal is output from the output 23. Is reflected and the reflected light is output from 25. This reflected light is used as a detector 12
, And controls the laser diode drive circuit to cut off the optical output of the excitation laser diode. As a result, the optical fiber amplifier stops amplification. When the disconnection of the optical connector is released using the optical connector disconnection release terminal 21 and the laser drive circuit is controlled from the state where the optical signal is cut off, the excitation laser diode emits light and the optical signal is momentarily amplified. At this time, if the optical connector is connected, the optical signal is output as it is, but if the optical connector is not connected, the reflected light is detected by the detection circuit to cut off the optical signal. As described above, every time the disconnection of the optical connector is detected, an amplified optical signal is output, albeit momentarily. Since this optical signal has a large output, there is a problem of an obstacle when it enters the eyes.

[0004]

An optical fiber amplifier according to the present invention comprises: a first driving circuit for outputting a first pumping light to a first laser diode; an input signal light; and the first pumping light. A first optical multiplexer and an isolator for wavelength-combining, an erbium-doped fiber for optically amplifying the wavelength-combined light, and a second drive circuit for outputting a second pumping light to a second laser diode. A second optical multiplexer and an isolator for wavelength-combining the amplified light from the fiber and the second pump light, an optical filter for passing only the wavelength-combined amplified light, and a third laser diode. A third drive circuit for outputting weak light, an optical switch for switching the amplified light to the weak light by a switching signal and outputting the light, an optical splitter for splitting and outputting the signal light from the optical switch, First photodiode signal light
An automatic output power control circuit by the in-converted first electrical signal for controlling said first and second driving circuits, optical connectors
The light component reflected when the light comes off the optical signal output terminal.
Converting the optical splitter and the output signal light reflected by from岐器, a second Hotoda <br/> diode for outputting a second electrical signal, the second electrical signal is preset Outputs the switching signal when the reference value is reached, and releases the connector
The switching signal is output even if the release signal is input from the terminal.
And a detector that continues .

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the present invention.

An optical signal is input from an optical input signal terminal 1,
An optical multiplexer 2 and an isolator 3 for wavelength-synthesizing the input signal light and a pump laser diode 18 for forward pumping.
The erbium-doped fiber 4 for wavelength-combined optical amplification, the optical multiplexer 5 and the isolator 6 for wavelength-combining the output of the fiber 4 and the pump laser diode for backward pumping, and the light of the pump laser diode 16 A long wavelength bandpass filter 7 that outputs only signal light without outputting,
An optical switch 8 operating at the output of the detector 12, an optical splitter 9 for splitting the optical output, a photodiode 11 for splitting in the same direction as the optical output and converting it to an electric signal, and a signal converted to an electric signal; An automatic output power control circuit (APC circuit) 13 for controlling the laser drive circuits 17 and 19 so that the optical output is constant, and branching in the opposite direction to the optical output signal and converting it into an electric signal. A photodiode 12, a detector 12 that compares the electric signal and outputs a signal when a certain level is reached, laser driving circuits 17 and 19 that cut off the light output using the output of the detector, and one side of the optical switch 8. Laser drive circuit 15 and laser diode 14
And

In this way, when the optical connector is not connected to the optical signal output terminal 20, the photodiode 1
0 converts the reflected light from the optical splitter 9 into an electric signal, which is detected by the detector 12. Using the output of the detector 12, the optical switch 8 is switched to a laser diode 14 having a low optical output power. At the same time, the laser drive circuits (17, 19) are controlled so that the outputs of the optical amplifiers are turned off, and the outputs of the pump laser diodes 16 , 18 are turned off.

[0008]

As described above, the present invention provides an optical connector
When the data comes off the optical signal output terminal, the reflected light from the optical branching device is detected, and the laser is switched to a laser diode with a low optical output power by an optical switch, and the connector is released from the disconnection release terminal.
By disabling the release signal, the optical signal output terminal
This has the effect of preventing the emission of an optical signal having a high intensity .

[Brief description of the drawings]

FIG. 1 is a block diagram of an optical fiber amplifier according to one embodiment of the present invention.

FIG. 2 is a diagram for explaining an operation of the optical splitter.

FIG. 3 is a block diagram illustrating an example of a conventional optical fiber amplifier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical input signal terminal 2, 5 Optical multiplexer 3, 6 Isolator 4 Erbium-doped fiber 7 Long wavelength band pass filter 8 Optical switch 9 Optical splitter 10, 11 Photodiode 12 Detector 13 APC circuit 14 Laser diode 15, 17 , 19 Laser drive circuit 16, 18 Excitation laser diode 20 Optical output signal terminal 21 Connector disconnection release terminal

Claims (1)

(57) [Claims] 1. A first driving circuit for outputting a first pumping light to a first laser diode, a first optical multiplexer and an isolator for wavelength-combining an input signal light and the first pumping light. An erbium-doped fiber that amplifies light with the wavelength-combined light, and a second laser diode.
A second drive circuit for outputting the pump light of the second type, and a second drive circuit for wavelength-combining the amplified light from the fiber and the second pump light.
An optical multiplexer and an isolator, an optical filter that allows only the wavelength-combined amplified light to pass therethrough, a third drive circuit that outputs a weak light to a third laser diode, and a switching signal that converts the amplified light to the weak light An optical switch for switching to light for output, an optical splitter for splitting and outputting the signal light from the optical switch, and a first photo diode for outputting the split signal light .
An automatic output power control circuit for controlling the first and second driving circuit by a first electrical signal converted by diode, light
Before reflection when the connector comes off the optical signal output terminal
A second photodiode for converting the output signal light reflected by the optical splitter from the optical splitter and outputting the converted signal light as a second electrical signal; and wherein the second electrical signal is preset. wherein outputs a switching signal when it becomes the reference value, the connector out
Switch signal even if a release signal is input from the release terminal.
Optical fiber amplifier; and a detector continues to output a.