JPH03239028A - Optical repeater system - Google Patents

Abstract

PURPOSE:To increase a main signal and a supervisory system signal at a high gain altogether by connecting a high diffusion optical fiber to both input and output terminals of a repeater and applying Raman amplification in forward and reverse directions with a pump wave from the repeater in the region of the high diffusion optical fiber respectively. CONSTITUTION:An optical input signal to a repeater 1 is inputted while being subject to Raman amplification at an optical coupler CPL1 with a pump wave from a laser diode LD1. Then the output of the optical coupler CPL1 is branched at a beam splitter BS to monitor the power of optical input and converted into an electric signal at an optoelectric conversion section O/E1 and a supervisory section SV supervises the power level. Then the optical output from an optical coupler CPL2 is subject to Raman amplification at an optical coupler CPL3 by using a pump light of a laser diode LD3 controlled by the supervisory section SV and send to a high diffusion optical fiber 3.

Description

[Detailed Description of the Invention] [Summary] Regarding a method of directly amplifying and relaying an optical signal, the purpose of this invention is to realize a method in which the light itself is subject to relay processing using an optical fiber Baraman amplification method. A high dispersion optical fiber is connected to both input and output ends of the repeater, and the optical input signal and the optical output signal, in which the main signal and the monitoring system signal are wavelength-multiplexed, are pumped from the repeater in the region of the high dispersion optical fiber. It is configured to perform Raman amplification in the forward direction and backward direction using light, respectively.

[Industrial application field]

The present invention relates to an optical relay system, and particularly to a system for directly amplifying and relaying optical signals.

The optical repeating system currently in practical use uses a repeater to convert light into electricity, amplify and shape it, and then convert this electrical signal back into light using a semiconductor laser, etc. Then, (1) the speed of the signal to be processed is limited by the bit rate determined by the electrical circuit, and (2) the optical wavelength that can be used is limited.

On the other hand, in the optical relay method, which directly amplifies and shapes the optical signal and then relays it, the bit rate can be changed to 10 Gb/
Since bidirectional amplification and batch amplification of wavelength multiplexed signals can be carried out at any time up to the order of 20 seconds, adoption of this optical direct relay system is desired.

[Conventional technology and its section M] Direct optical amplification methods currently being researched include amplification methods using Er (erbium) doped fibers, semiconductor lasers, optical fiber optics, etc. Compared to other methods, this amplification method has the advantage that it has a wide amplification bandwidth, making wavelength multiplexing easier, and bidirectional amplification is possible because it does not have directionality like a semiconductor laser. have.

However, the current situation is that no optical relay system using an optical fiber Brahman amplification system has been proposed yet.

Therefore, an object of the present invention is to realize a system in which light itself is subject to relay processing using an optical fiber Brahman amplification system.

[Means to solve the problem]

In order to solve the above problems, in the optical repeating system according to the present invention, as conceptually shown in FIG. In the region of the optical fiber 2.3, the main signal and the monitoring signal are wavelength-multiplexed, and the optical input signal and optical output signal are subjected to forward and backward Raman amplification using pump light from the repeater 1, respectively. It is configured as follows.

[For production]

In the present invention, forward Raman amplification is performed on the optical input signal from the high dispersion optical fiber 2 by applying pump light from the repeater 1, and the signal is manually input to the repeater 1.

In this case, since a high dispersion optical fiber is used, the amplification bandwidth can be widened, and therefore, the optical input signal can be wavelength-multiplexed with the main signal and the monitoring signal, and can be amplified all at once.

By applying pump light from the rear direction to the optical signal output from the repeater 2, Raman amplification can be performed to obtain a high repeating gain due to two-stage amplification.

〔Example〕

Fig. 2 shows an embodiment of the optical repeating system according to the present invention. A forward optical coupler CPL that performs Raman amplification using the pump light from the laser diode LDI, which is controlled to a constant output.
1, and the power of the optical output from this forward optical coupler CPLI is branched and sent to the monitoring unit Sv via the optical-electrical converter ○/El.
A beam splitter BS is provided in the form of an electrical signal to the beam splitter BS, and a monitoring system signal is branched from the output of this beam splitter BS to other than the optical-to-electrical converter O/El.
A filter FL is provided in the form of an electrical signal to the monitoring unit Sv via E1, a signal other than the monitoring system branched from this filter FL, and a transfer monitoring system signal (opposite line) from the laser diode LD2 controlled by the monitoring unit SV. (including the monitoring system signal), and the optical output from this optical coupler CPL2 is Raman amplified by the pump light from the laser diode LD3, which is controlled to a constant optical output by the monitoring section Sv, and is highly dispersioned. It consists of a rearward optical coupler CPL3 that sends out data to the optical fiber 3 (shaded area).

The high dispersion optical fiber 2.3 was taken out of the repeater 1 because the fiber length required for amplification is longer for high dispersion optical fibers than for Er-doped fibers, and usually several tens of kg+ is required. This is because it is difficult to fit this into a repeater.

In the operation of the optical repeater system configured as described above, an optical input signal to the repeater 1 is Raman amplified by the optical coupler CPLL using pump light from the laser diode LDl, and then inputted.

The output from the optical coupler CPLI is then branched to monitor the optical input power at the beam splitter BS.
The electric converter 0/E1 converts it into an electric signal, and the monitor Sv monitors its power level.

Signals other than the power branch signal from the beam splitter BS are further branched into monitoring system signals by the filter FL, and similarly sent to the monitoring section Sv in the form of electrical signals, where they are used for various monitoring operations as is well known.

Other signals are combined with the monitoring system signal from the laser diode LD2 by the optical coupler CPL2, and then sent to the optical coupler CPL2.
Sent to 3.

Then, in the optical coupler CPL3, the optical output from the optical coupler CPL2 is Raman-amplified by the pump light of the laser diode LD3, which is also controlled by the monitoring section SV, and is sent to the high-dispersion optical fiber 3.

〔Effect of the invention〕

As described above, according to the optical repeating system of the present invention, high dispersion optical fibers are connected to both input and output ends of the repeater, and the main signal and the monitoring system signal are wavelength-multiplexed in the area of the high dispersion optical fibers. Since the optical input signal and the optical output signal are configured to be Raman amplified in the forward and backward directions using the pump light from the repeater, the advantages unique to the Raman amplification method are as follows: The main signal and the monitoring signal can be amplified all at once. ■ Since it has no directionality, two-stage amplification in the forward and backward directions is possible, resulting in high gain. Also, since it is an optical direct method, ■ A high bit rate can be achieved. Furthermore, since there is no need to house the high dispersion optical fiber in the repeater, the following effects can be achieved: (1) The repeater can be made smaller.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the basic configuration of an optical relay system according to the present invention, and FIG. 2 is a circuit block diagram showing an embodiment of the optical relay system according to the present invention. In Fig. 1, 1... repeater, 2.3... high dispersion optical fiber. In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A high dispersion optical fiber (2) is installed at both input and output ends of the repeater (1).
3) is connected to the optical input signal and the optical output signal, in which the main signal and the monitoring system signal are wavelength-multiplexed in the area of the high dispersion optical fibers (2) and (3), from the repeater (1). An optical relay system characterized by performing Raman amplification in the forward and backward directions using pump light.