JPH0447834A - Optical repeater - Google Patents

Abstract

PURPOSE:To detect the operational tolerance of an identifying and reproducing circuit in the repeater of the next step by varying the pulse signal of a low frequency to be superimposed to the main signal of a repeating output according to a control signal from a terminal station. CONSTITUTION:An electric signal from a light receiving device 1 is equalized, amplified and outputted after being branched into first and second signals 2a and 2b. A clock 3a is extracted from the signal 2a, and the signal 2b is identified by the clock 3a, reproduced and outputted after being branched into third and fourth signals 4a and 4b. According to the control signal added from the terminal station to the signal 4a, error rate information 7a and control information 7b are outputted. According to the error rate information 7a, a semiconductor laser 6 is driven by inputting the signal 4b whose phase is modulated. The output pulse 10 of a variable 9 to output the clock from a frequency divider circuit 8 while controlling the amplitude according to the control information 7b is superimposed to the signal 4b. Thus, the operational tolerance of the identifying and reproducing circuit in the repeater of the next step can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical repeater, and particularly to an optical repeater having a 3R function.

[Conventional technology]

The optical repeater uses a method of obtaining a reproduced optical pulse waveform by receiving an attenuated optical signal with a variable receiving element, converting it back into an electrical signal, reproducing and amplifying this electrical signal, and applying it to a light emitting element. This is called regenerative relay, and includes timing extraction (Retiming), equalization amplification, or waveform shaping (Retiming).
shaping) and identification regeneration (Regenerat).
It consists of three functions (Ing) and is called a 3R repeater.

FIG. 2 is a block diagram of an example of a conventional optical repeater.

a photoreceiver 11 that converts an input optical signal into an electrical signal and outputs it; an equalization amplifier 12 that equalizes and amplifies the electrical signal from the photoreceiver 11 and branches it into first and second signals 12a and 12b;
A timing extraction circuit 13 that outputs a clock 13a extracted from a first signal 12a, and a second signal 12b as an input.
is identified and reproduced by the clock 13a and the third and fourth signals 1
4a.

14b, a monitoring control circuit 17 that outputs error rate information 17a detected by the control signal from the terminal station added to the third signal 14a, and an identification reproducing circuit 14 that outputs the error rate information A drive circuit 1 that inputs the fourth signal 14b phase-modulated by 17a and drives the semiconductor laser 16.
5.

[Problem to be solved by the invention]

In the above-mentioned conventional optical repeater, the detection of false information in the supervisory control circuit is caused by deterioration of the output equalized waveform due to changes over time in the equalization amplifier circuit and phase fluctuations in the clock due to deterioration over time in the timing extraction circuit, etc. There is a problem in that the margin of operation for identifying data cannot be determined due to drift of the transistors that make up the data.

[Means to solve the problem]

The optical repeater of the present invention includes a means for receiving a main optical signal to which a transmission control signal is added from a terminal station, converting it into an electrical signal and outputting it, and performing identification and reproduction using a taro signal extracted from the equalized and amplified electrical signal. means for outputting the detected electrical signal; means for outputting false information and control information from the detected control signal; means for adding the false information to the identified and reproduced electrical signal and outputting it as a main signal; The control device includes means for adjusting the level of the clock that has been generated according to the control information and superimposing it on the main signal, and means for converting the main signal from this means into electrical light and transmitting it.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

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

a light receiver 1 that converts an input optical signal into an electrical signal and outputs it;
an equivalent amplifier 2 that equalizes and amplifies the electrical signal from the photoreceiver 1 and outputs it branched into first and second signals 2a and 2b; a timing extraction circuit 3 that outputs a clock 3a extracted from the first signal 2a; An identification and regeneration circuit 4 that identifies and regenerates the input second signal 2b using a clock 3a and branches it into third and fourth signals 4a and 4b, and a control signal from the terminal station added to the third signal 4a. The monitoring control circuit 7 outputs the detected error rate information '7a and the control information 7b, and the drive unit inputs the fourth signal 4b phase-modulated by the error rate information 7a to the identification reproducing circuit 4 to drive the semiconductor laser 6. a circuit 15, a frequency dividing circuit 8 that divides and outputs the clock 3a, a variable attenuator 9 that controls the amplitude of the clock from the frequency dividing circuit 8 using control information 7b and outputs it, and an output pulse 10a of the variable attenuator 9. The fourth
The switch 10 is configured to superimpose the signal 4b on the signal 4b.

In this way, the signal output from the semiconductor laser 6 is degraded by the control signal that sends the output pulse 10a superimposed on the fourth signal 4b from the terminal station, thereby increasing the operating margin of the identification and reproducing circuit of the next stage repeater. can be detected.

〔Effect of the invention〕

As explained above, the present invention can detect the operating margin of the identification regeneration circuit of the next-stage repeater by varying the low-frequency pulse signal superimposed on the main signal of the relay output using a control signal from the terminal station. It has this effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of an example of a conventional optical repeater. DESCRIPTION OF SYMBOLS 1... Light receiver, 2... Equalization amplifier circuit, 3... Timing extraction circuit, 4... Identification and regeneration circuit, 5... Drive circuit, 6... Semiconductor laser, 7... supervisory control circuit,
8... Frequency divider circuit, 9... Variable attenuator, 10... Switch.

Claims (1)

[Claims] means for receiving an optical main signal to which a transmission control signal is added from a terminal station, converting it into an electrical signal and outputting it; and means for outputting an electrical signal identified and reproduced using a clock extracted from the equalized and amplified electrical signal. , means for outputting erroneous information and control information from the detected control signal, means for adding the erroneous information to the identified and reproduced electrical signal and outputting it as a main signal, and adding the frequency-divided clock to the control information. An optical repeater comprising means for adjusting the level accordingly and superimposing it on the main signal, and means for converting the main signal from the means into electrical light and transmitting it.