JPH04236527A - Optical repeater - Google Patents

Abstract

PURPOSE:To easily phase-modulate a transmission signal based on monitor information. CONSTITUTION:An inputted optical signal is converted into an electric signal by an O.E conversion section 11, equalized and amplified by a reception amplifier 12 and the result is inputted to an identification circuit 13 and a timing circuit 14. A timing signal extracted by the timing circuit 14 is used to allow the identification circuit 13 to identify and recover the transmission signal. The identified and recovered signal is converted into an optical signal by a light source drive circuit 15 and a light source 16 and made incident on an optical fiber. A control signal is extracted from the identified and recovered signal by a monitor control circuit 17 and the control signal is used to collect monitor information in the optical repeater. A wavelength control circuit 18 controls the wavelength of the output light from the light source 16 based on the monitor information from the monitor control circuit 17. Since the optical transmission speed in the optical fiber depends on the wavelength, the optical signal after the transmission through the optical fiber is in the phase-modulation state.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical repeater having a monitoring function.

0002

2. Description of the Related Art In recent years, optical communication systems that transmit information using light have been put into practical use. This optical communication system requires an optical relay system to transmit information over long distances. In this optical repeater system, the optical repeater is required to have a monitoring function in order to search for failure points. In particular, submarine relay systems require monitoring of service status from the viewpoint of failure prevention and maintenance. However, in optical relay systems, monitoring lines are generally not installed, so parity violations are used for control signals for monitoring, and phase modulation is used for response signals when transmitted together with information signals. There are many.

FIG. 2 shows an example of a conventional optical repeater. In this optical repeater, an optical signal input from a line is converted into an electrical signal by an optical-to-electrical converter (hereinafter referred to as O/E converter) 11, and then converted to a constant amplitude by a receiving amplifier 12. The signal is amplified so as to be input to the identification circuit 13 and the timing circuit 14. The identification circuit 13 uses the timing signal extracted from the output signal of the reception amplifier 12 by the timing circuit 14 to identify and reproduce the transmission signal. The identified and reproduced signal passes through the phase modulation circuit 19, the light source drive circuit 15, and the light source 26, and is again transmitted to the line as an optical signal. In addition, the monitoring control circuit 17 extracts the control signal superimposed due to parity violation etc. from the signal identified and reproduced by the identification circuit 13, and collects monitoring information in the repeater such as E/O bias and input power. Then, this monitoring information is transmitted to the terminal station by subjecting the transmission signal to phase modulation in the phase modulation circuit 19.

0004

[Problems to be Solved by the Invention] However, in the conventional optical repeater described above, since an electric circuit is used for the phase modulation circuit 19, there is a problem that as the transmission speed increases, it becomes difficult to realize phase modulation. There is.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical repeater that can easily phase-modulate a transmission signal based on monitoring information.

[0006]

[Means for Solving the Problems] An optical repeater according to the invention as set forth in claim 1 includes an optical-to-electrical conversion means for receiving an optical signal and converting it into an electric signal, and a relay for relaying an output signal of the optical-to-electrical conversion means. a relay means for converting the output signal of the relay means into an optical signal and inputting it into an optical fiber; a monitoring means for monitoring the optical repeater and outputting monitoring information;
The apparatus includes wavelength control means for controlling the wavelength of the optical signal input to the optical fiber based on the monitoring information from the monitoring means.

In this optical repeater, an optical signal is converted into an electrical signal by an optical-to-electrical conversion means, an output signal from the optical-to-electrical conversion means is relayed by a relaying means, and an output signal from this relaying means is converted into an electrical-to-electrical conversion means. The optical signal is converted into an optical signal by a means, and this optical signal is input into an optical fiber. Further, the optical repeater is monitored by the monitoring means, and monitoring information is output from the monitoring means. Based on this monitoring information,
The wavelength control means controls the wavelength of the optical signal input to the optical fiber. Since the optical transmission speed in an optical fiber differs depending on the wavelength, by controlling the wavelength of the optical signal by the wavelength control means, the optical signal after being transmitted through the optical fiber becomes in a phase modulated state.

In the optical repeater according to the invention set forth in claim 2, the electrical/optical conversion means in the optical repeater according to the invention set forth in claim 1 has a light source whose output light has a variable wavelength, and the wavelength control means has a variable wavelength output light source. The wavelength of the optical signal input to the optical fiber is controlled by controlling the wavelength of the output light of the optical fiber.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an optical repeater according to an embodiment of the present invention.

The optical repeater of this embodiment includes an O/E converter 11 that receives an optical signal input from a line using an optical fiber and converts it into an electrical signal, and an output of the O/E converter 11. The receiving amplifier 12 equalizes and amplifies the signal to a constant amplitude. The output signal of this receiving amplifier 12 is input to an identification circuit 13 and a timing circuit 14. The timing circuit 14 is connected to the receiving amplifier 12
The timing signal is extracted from the output signal of the identification circuit 13.
uses this timing signal to identify and reproduce the transmitted signal. The reception amplifier 12, the identification circuit 13, and the timing circuit 14 constitute a regenerative relay means having so-called 3R functions of equalization amplification, retiming, and identification reproduction. The signal identified and reproduced by the identification circuit 13 is transmitted to the light source drive circuit 15 and the monitoring control circuit 1.
7 is input. The light source drive circuit 15 is configured to superimpose a carrier wave of a predetermined frequency on the transmission signal output from the identification circuit 13. The light source 16 is driven by the output signal of the light source drive circuit 15, and the transmission signal is converted into an optical signal. This optical signal is made to be input into an optical fiber. The light source 16 is a light source whose wavelength of output light is variable, and the wavelength of the output light is changed under the control of the wavelength control circuit 18.

The monitoring control circuit 17 also includes an identification circuit 13.
The control signal superimposed due to parity violation etc. is extracted from the identified and regenerated signal, and various monitoring operations of the optical repeater are performed according to this control signal, and the optical repeater monitors the E/O bias, input power, etc. It is designed to collect monitoring information inside the device. This monitoring information is transmitted to the wavelength control circuit 18
is now entered. The wavelength control circuit 18 is
The wavelength of the output light from the light source 16 is controlled based on monitoring information from the monitoring control circuit 17.

In this embodiment configured as described above, the optical signal input from the line using the optical fiber is O.E.
It is converted into an electrical signal by a converter 11, and then sent to a receiving amplifier 1.
The signal is equalized and amplified by 2 and input to the identification circuit 13 and the timing circuit 14. The identification circuit 13 uses the timing signal extracted from the output signal of the reception amplifier 12 by the timing circuit 14 to identify and reproduce the transmission signal. The signal identified and reproduced by the identification circuit 13 is input to the light source drive circuit 15, and a carrier wave of a predetermined frequency is superimposed thereon. Then, the light source 16 is driven by the output signal of the light source drive circuit 15, the transmission signal is converted into an optical signal, and this optical signal is input into the optical fiber and transmitted to the terminal station.

The monitoring control circuit 17 also includes an identification circuit 13.
extracts a control signal from the identified and regenerated signal, performs various monitoring operations on the optical repeater according to this control signal, collects monitoring information within the optical repeater, and sends this monitoring information to the wavelength control circuit. Output to 18. The wavelength control circuit 18 controls the wavelength of the output light from the light source 16 based on monitoring information from the monitoring control circuit 17. Since an optical fiber has dispersion and the optical transmission speed in the optical fiber varies depending on the wavelength, the wavelength control circuit 1
8 modulates the wavelength of the output light from the light source 16, so that the optical signal after being transmitted through the optical fiber becomes in a phase modulated state. Therefore, by performing phase detection at the terminal station, the monitoring information of the optical repeater can be reproduced.

According to this embodiment, the wavelength control circuit 18 adjusts the wavelength of the output light from the light source 16 based on the information from the monitoring control circuit 17 without directly applying phase modulation to the transmission signal using an electric circuit. We applied modulation to the optical fiber so that the optical signal after transmission is in a phase modulated state.
Even if the transmission speed becomes high, the transmission signal can be easily phase modulated.

[0015]

As explained above, according to the present invention, by controlling the wavelength of the output light of the light source, for example, based on the monitoring information from the monitoring means, the wavelength of the output light from the optical repeater and entering the optical fiber is controlled. Since the wavelength of the optical signal transmitted through the optical fiber is controlled so that the optical signal is in a phase modulated state after being transmitted through the optical fiber, there is an effect that the transmitted signal can be easily phase modulated.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an optical repeater according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of a conventional optical repeater.

[Explanation of symbols]

11 O/E converter 12 Receiving amplifier 13 Identification circuit 14 Timing circuit 15 Light source drive circuit 16 Light source 17 Monitoring control circuit 18 Wavelength control circuit

Claims (2)

[Claims] Claim 1: Optical-to-electrical conversion means for receiving an optical signal and converting it into an electrical signal; relaying means for relaying the output signal of the optical-to-electrical conversion means; and converting the output signal of the relaying means into an optical signal. an electrical/optical conversion means that monitors the optical repeater and outputs monitoring information; and an optical signal that is input into the optical fiber based on the monitoring information from the monitoring means. 1. An optical repeater comprising: wavelength control means for controlling the wavelength of the optical repeater. 2. The electrical-to-optical conversion means includes a light source whose output light has a variable wavelength, and the wavelength control means controls the wavelength of the output light of the light source to control the wavelength of the optical signal input to the optical fiber. Claim 1 characterized in that the wavelength is controlled.
The optical repeater described.