JPH05344073A - Optical repeater - Google Patents

Abstract

PURPOSE:To allow a terminal station to confirm it that the optical repeater receives a monitor control signal sent from the terminal station. CONSTITUTION:When a monitor control signal arrives from an incoming transmission line, an oscillator 5 is oscillated at a frequency f1 and the f1 signal is inputted to a bias current supply circuit 7 of an optical amplifier 6. The optical amplifier 6 uses the fl signal to amplitude-modulate the transmission optical main signal 103 from the incoming transmission line. When the monitor control signal arrives from an outgoing transmission line, an oscillator 17 oscillates an f2 signal to amplitude-modulate the transmission optical main signal 102 to the outgoing transmission line. A terminal station side receives the f1, f2 signals to confirms it that the control monitor signal reaches the optical repeater.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical repeater using an erbium-doped fiber type optical amplifier, and more particularly to an optical repeater capable of obtaining a response signal to a supervisory circuit control signal.

[0002]

2. Description of the Related Art In this type of optical repeater, a supervisory control signal from a terminal station is received to perform a loopback test or control an optical signal for pumping an optical amplifier. This supervisory control signal is transmitted to the optical repeater side by modulating the amplitude of the optical main signal shallowly at the terminal side, and the optical repeater side branches this optical main signal and converts the branched optical main signal into an electrical signal. After converting
It is detected by the filter. When the optical repeater receives the supervisory control signal, the signal of the reception response to the terminal side was required as a confirmation signal, but it is not generally provided because the device becomes complicated due to problems such as the transmission method. ..

[0003]

As described above, in the conventional example, since the response signal is not returned to the terminal station side in response to the reception of the monitor control signal, the terminal station side cannot confirm the arrival of the monitor control signal. In particular, when performing a loopback test using a supervisory control signal, the optical repeater repeats the optical main signal to detect subtle power fluctuations of the optical main signal that has returned to the terminal side. However, there was no standard for judgment, and it was inaccurate. There is also a problem that it is not possible to determine whether the optical repeater designated by the supervisory control signal is actually turned back.

[0004]

An optical repeater according to the present invention comprises a first optical amplifier for amplifying an optical signal from an upstream reception transmission line by using an erbium-doped fiber and transmitting the amplified optical signal to a downstream transmission line. The optical signal sent from the first optical amplifier is branched, and the optical signal from the downstream receiving transmission path is detected by the first monitoring control unit that detects the monitoring control signal from the branched optical signal.
A second optical amplifier that amplifies using a doped fiber and sends out to an upstream transmission line, and a second supervisory control for branching an optical signal sent out by the second amplifier and detecting a supervisory control signal from the branched optical signal An optical repeater including a second monitoring control unit, the bias current of the pumping light generating laser diode of the second optical amplifier is modulated at a predetermined modulation frequency by the output signal of the first monitoring control unit, and the second monitoring control is performed. The bias current of the pumping light generating laser diode of the first optical amplifier is modulated at a predetermined modulation frequency by the output signal of the section.

When the optical repeater is used in a system in which a plurality of optical repeaters are connected, the modulation frequency is selected by the optical repeater.

[0006]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an optical repeater showing an embodiment of the present invention.

When the supervisory control of the optical repeater is performed, the supervisory control signal specially assigned to the present optical repeater is superposed on the upstream main signal light and transmitted from the terminal station side.

In FIG. 1, a received light main signal 101 on which a supervisory control signal for an upstream transmission path is superimposed is input to the erbium-doped fiber 12 with the pumping light emitted by the pumping light laser diode 10 in the optical amplifier 1. It will be amplified. The main signal light amplified by the optical amplifier 1 is branched into two by the optical distributor 2 of the monitor and control unit 20, one is transmitted to the next repeater as the transmission optical main signal 102, and the other is transmitted to the optical-electrical converter 3. It is input and converted into an electrical signal. This electric signal is a main signal on which the supervisory control signal is superimposed, and this supervisory control signal is detected by the next supervisory control circuit 4.

This detection signal is applied to the oscillator 5, and the oscillator 5 outputs a signal of the oscillation frequency f1 to the bias current supply circuit 7 of the optical amplifier 6 while the detection signal is input. The bias current supply circuit 7 outputs the output signal f1 of the oscillator 5.
In response, the bias current of the laser diode 8 for pumping light is modulated with the signal of frequency f1. As a result, the power of the pumping light S5 is modulated, and the transmission light main signal light 103 on the upstream transmission path is amplitude-modulated and sent to the terminal station side. At the terminal station, the oscillation frequency f1 peculiar to the present optical repeater is extracted from the main signal light 103 and it is confirmed that the supervisory control signal of the main signal light 101 is received by the present repeater.

On the other hand, similarly to the downlink transmission line side, the terminal station on the downlink transmission line side can receive the starting frequency f2 of the oscillator 17 by transmitting the monitoring control signal, and the monitoring control signal in the optical repeater can be received. You can check the arrival of. In a multi-stage repeater bidirectional transmission system with multiple optical repeaters, if a unique oscillation frequency is assigned to each optical repeater, the arrival of the supervisory control signal for each optical repeater can be confirmed on the terminal side. it can.

[0011]

As described above, according to the present invention, the arrival of the supervisory control signal of each optical repeater can be confirmed for each repeater, so that the supervisory control operation on the terminal side can be performed reliably and efficiently. There is an effect that can be done.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

[Explanation of Reference Signs] 1,6 Optical amplifier 2,13 Optical distributor 3,15 Optical-electrical converter 4,16 Supervisory control circuit 5,17 Oscillator 7,11 Bias current supply circuit 8,10 Excitation light laser diode 9 , 14 Optical combiner 12, 17 Erbium-doped fiber 20, 21 Monitoring and control unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H04B 10/08

Claims (2)

[Claims] 1. A first optical amplifier for amplifying an optical signal from an upstream receiving transmission line by using an erbium-doped fiber and sending it to a downstream transmitting transmission line, and an optical signal sent out by the first optical amplifier. A first supervisory controller for detecting a supervisory control signal from the branched optical signal, and a second optical amplifier for amplifying the optical signal from the downlink receiving transmission line by using an erbium-doped fiber and sending it to the upstream transmitting transmission line. And an output signal of the first monitoring control unit in an optical repeater including: a second monitoring control unit that branches the optical signal transmitted by the second amplifier and detects the monitoring control signal from the branched optical signal. The bias current of the pumping light generating laser diode of the second optical amplifier is modulated at a predetermined modulation frequency, and the pumping light generating laser diode of the first optical amplifier is generated by the output signal of the second monitoring controller. An optical repeater characterized in that the bias current of the above is modulated at a predetermined modulation frequency. 2. The optical repeater according to claim 1, wherein when the optical repeater is used in a system in which a plurality of optical repeaters are connected, a specific frequency is selected by the optical repeater as the modulation frequency. vessel.