JPH04236526A - Optical repeater - Google Patents

Abstract

PURPOSE:To allow the optical repeater to easily cope with fluctuation of a level of an optical signal such as a level increase due to insertion of a standby optical repeater. CONSTITUTION:An inputted optical signal is converted into an electric signal by an O.E conversion section 11, the electric signal is waveform-shaped by a recovery circuit 12 and the result is inputted to an A side E.O conversion section 13 and a B side E.O conversion section 14. The E.O conversion sections 13, 14 convert the received signal into an optical signal of linearly polarized light whose polarized planes are orthogonal to each other. The output light from the E.O conversion sections 13, 14 is given to attenuators 16, 17 whose attenuation is different and an optical element 18 having a double refraction characteristic outputs the lights to a same optical axis. A command reception section 15 detects and recognizes a command signal commanding switching of an output light of an optical submarine repeater from an output signal of the O.E conversion section 11 to activate one of the E.O conversion sections 13, 14.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical repeater, and more particularly to an optical repeater suitable for an optical submarine repeater system.

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. Conventionally, among these optical relay systems, in the optical submarine relay method that uses optical cables laid on the ocean floor,
The route for laying the optical submarine cable is determined after investigation, and the span of each repeater is determined by considering the output power and reception level of the optical submarine repeater.

0003

[Problems to be Solved by the Invention] In this conventional optical submarine repeater system or optical submarine repeater, if the optical submarine cable is cut by a fishing boat, etc. after it has been installed, it is necessary to temporarily remove the cable for repair. The cable will be pulled up and reconnected, but due to construction reasons, it may be necessary to insert (add) a spare cable. If the reception level of the above-mentioned optical submarine repeater no longer satisfies the standard due to the increased loss caused by this inserted cable, it becomes necessary to also insert a spare repeater.

However, at the design stage of optical submarine relay systems, the relay span is optimized, so when a spare repeater is inserted, this spare repeater or the adjacent repeater The reception level of the repeater has become too high and some attenuator is required. This attenuator is installed in what is called an optical submarine repeater or joint box, but this work must be done during the installation work, which is extremely dangerous and poses problems in terms of reliability. There is a problem.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical repeater that can easily cope with fluctuations in the level of an optical signal, such as an increase in the level due to the use of a spare optical repeater. be.

[0006]

[Means for Solving the Problems] An optical repeater according to the invention as set forth in claim 1 is provided with a repeating means for repeating and outputting an input optical signal, and a switching means for switching the level of output light of the repeating means. By switching the level of the output light of the relay means by the switching means, the level of the output optical signal of the optical repeater can be changed.

The optical repeater according to the second aspect of the invention comprises: an optical-to-electrical conversion means for converting an input optical signal into an electric signal; a relay means for relaying an output signal of the optical-to-electrical conversion means;
Two electrical/optical converting means input the output signal of this relaying means and convert it into two linearly polarized optical signals whose polarization planes are orthogonal to each other, and input the output lights of these two electrical/optical converting means and input the same signal. An optical element having birefringence that is output on the optical axis, and an output of at least one of the electric-to-optical conversion means so that the levels of the output light of the two electric-to-optical conversion means that are input to this optical element are different. In order to switch the light attenuation means inserted on the optical path of the light and the output light level of the optical element,
It is provided with a selection means for selectively operating one of the two electric/optical conversion means.

In the second aspect of the invention, the input optical signal is converted into an electrical signal by the optical-to-electrical converting means, relayed by the relaying means, and input to the two electrical-to-optical converting means. The output lights of these two electrical/optical conversion means are output on the same optical axis via an optical element. Since the optical attenuation means is inserted on the optical path of the output light of at least one of the electric-to-optical converters so that the levels of the output lights of the two electric-to-optical converters that are input to the optical element are different, the selection means By selectively operating one of the two electrical/optical conversion means, the level of the output light of the optical element is switched.

[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.

This embodiment is an example in which the present invention is applied to an optical submarine repeater used in an optical submarine repeater system. This optical submarine repeater includes an optical-to-electrical converter (hereinafter referred to as O/E converter) 11 that inputs an optical signal transmitted by an optical submarine cable and converts it into an electrical signal, and this O/E converter. a reproducing circuit 12 that inputs the output signal of the O/E converter 11, shapes the waveform, and relays it; and a command signal receiver 15 that inputs the output signal of the O/E converter 11 and detects and recognizes a command signal included in the input optical signal. It is equipped with The command signal is
This is a signal that instructs switching of the output light level of an optical submarine repeater.

The output signal of the reproducing circuit 12 is processed by two electrical/optical converters (hereinafter referred to as E/O converters) that convert this output signal into two linearly polarized optical signals whose polarization planes are orthogonal to each other. That is, it is input to the A-side E/O converter 13 and the B-side E/O converter 14. A side E・O
The converter 13 emits an ordinary light wave P, and the B side E/O converter 14
is designed to emit an extraordinary light wave S. An A-side attenuator 16 and a B-side attenuator 17 are inserted on the optical path of the output light of each E/O converter 13 and 14, respectively. The attenuators 16 and 17 have different amounts of loss, and one of them may have a loss of zero. Alternatively, only one attenuator may be provided. The output light from each of the E/O converters 13 and 14 is made to enter two input surfaces of an optical element 18 having birefringence, such as calcite. The output lights of the E/O converters 13 and 14 that have entered this optical element 18 are output on the same optical axis, and the output lights of this optical element 18 are transmitted to the submarine cable as output optical signals of the optical submarine repeater. It is designed to be incident.

The command receiving section 15 also detects and recognizes a command signal, and sends a control signal a for putting the A-side E/O converter 13 into an operating state and a control signal a for putting the B-side E/O converter 14 into an operating state. One of the signals b is output.

In this embodiment configured as described above, an optical signal transmitted by an optical submarine cable and inputted to an optical submarine repeater is converted into an electrical signal by an O/E converter 11, The waveform is shaped by
The signal is input to the O converter 13 and the B-side E/O converter 14. In addition, the optical signal from the land station includes a signal instructing the switching of the output light level of the optical submarine repeater, that is, the A side E/O
A command signal for activating one of the converting section 13 and the B-side E/O converting section 14 is incorporated, and this command signal is detected and recognized by the command receiving section 15. The command receiving section 15 outputs one of the control signal a and the control signal b based on the recognized command signal, and puts one of the A-side E/O converter 13 and the B-side E/O converter 14 into an operating state. shall be. The output light from the E/O converter in the operating state passes through the attenuator 16 or 17, and is output via the optical element 18.

As described above, according to this embodiment, the A-side E/O converter 13 and the B-side E/O converter 1 are
4, it is possible to select one of the A-side attenuator 16 and the B-side attenuator 17, which have different amounts of loss from each other. You can switch the output light level of the device.

For example, if the loss amount of the A-side attenuator 16 is set to zero and the loss amount of the B-side attenuator 17 is set to several dB, normally
If the level of the optical signal increases as a result of putting the side E/O converter 13 into operation, cutting the optical submarine cable, and inserting a spare optical submarine cable and a spare optical submarine repeater, the B side With the E/O converter 14 in the operating state, the optical signal is converted to B.
By passing the optical signal through the side attenuator 17, the level of the optical signal can be adjusted to an appropriate level.

Note that the present invention is not limited to the above-described embodiment, and for example, the output lights of each attenuator 16 and 17 may be output on the same optical axis using a polarizing beam splitter. Furthermore, the level of the optical signal may be switched by inserting and removing an attenuator in the optical path of the output light of one E/O converter.

[0017]

As explained above, according to the present invention, the level of the output optical signal of the optical repeater can be switched, so that the level of the optical signal can be changed, such as increasing the level by inserting a spare optical repeater. This has the effect of being able to easily deal with level fluctuations.

[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.

[Explanation of symbols]

11 O/E conversion section 12 Regeneration circuit 13　A side E/O conversion section 14　B side E/O conversion section 15 Command receiving section 16 A side attenuator 17 B side attenuator 18 Optical element

Claims (2)

[Claims] 1. An optical repeater comprising: repeating means for repeating and outputting an input optical signal; and switching means for switching the level of output light from the repeating means. 2. Optical-to-electrical conversion means for converting an input optical signal into an electric signal; relay means for relaying the output signal of the optical-to-electrical conversion means; Two electrical/optical conversion means that convert into two linearly polarized optical signals whose planes are perpendicular to each other, and these two electrical/optical converters.
An optical element having birefringence that inputs the output light of the light conversion means and outputs it on the same optical axis, and an optical element that inputs the output light of the light conversion means and outputs it on the same optical axis, so that the levels of the output lights of the two electric/optical conversion means that are input to this optical element are different, An optical attenuation means inserted on the optical path of the output light of at least one of the electric-to-optical conversion means and one of the two electric-to-optical conversion means to selectively switch the level of the output light of the optical element. An optical repeater comprising: selection means for operating.