JP2626178B2 - Optical amplification repeater - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical amplification repeater, and more particularly, to an optical amplification repeater using a doped fiber for amplifying a main optical signal.

[Conventional technology]

Conventionally, as shown in FIG. 4, this type of optical amplification repeater uses the output of a pumping light source 15 for pumping a main optical signal as a second output of a multiplexer 11.
Of the multiplexer 11 is coupled to the main signal input to the first input of the multiplexer 11, and the output of the multiplexer 11 is connected to an Er-doped fiber.
This is an optical amplifier that performs optical amplification through 12 and cuts off the excitation light by the demultiplexer 13, which is a pump light source with high optical output required for optical amplification.
15 consisted of one.

[Problems to be solved by the invention]

In the above-described conventional optical amplifier repeater, when the optical output power of the pump light source having a high optical output required for optical amplification is reduced, the optical amplification characteristics are deteriorated.

In addition, since the pump light source is required to have a small size and a long service life, which is in conflict with the high light output characteristics, a method of making the pump light source redundant has been considered. Since the side is used as a cold standby, there is a disadvantage that a code error is given to the main line system when switching from the working pump source to the standby pump light source.

[Means for solving the problem]

An optical amplifying repeater according to a first aspect of the present invention includes a first pump light source that emits a first optical power, a second pump light source that emits a second optical power, and the first or second input light source. An optical coupler that outputs an electric signal photoelectrically converted according to the amount of optical power of
A multiplexer for multiplexing and outputting the first or second optical power from the optical coupler and a main signal of the relay light, and a doped fiber for optically amplifying an output from the multiplexer; A monitoring circuit for switching between the first and second excitation light sources that is driven when the electric signal falls below a preset threshold.

An optical amplification repeater according to a second aspect of the present invention includes a plurality of pumping light sources that emit optical power, an optical coupler that outputs an electrical signal photoelectrically converted according to a sum of photoelectrics from the plurality of optical powers, A multiplexer for multiplexing the sum of the optical power from the optical coupler and a main signal of the light to be relayed, a doped fiber for optically amplifying an output from the multiplexer, and the electric signal being preset. An automatic power adjustment circuit for driving the plurality of excitation light sources so that the reference value is obtained.

〔Example〕

Next, the present invention will be described with reference to the drawings. FIG. 1A is a block diagram of a first embodiment of the present invention.

It is assumed that the first pumping light source 5 is working and the second pumping light source 6 is standby, and the working pumping light source 5 is normally operating. The optical output of the pump light source 5 is input to the optical coupler 4, and the pump light from the optical coupler 4 is input to the multiplexer 1 together with the main signal to be relayed and multiplexed. The output from the multiplexer 1 is Er
After the optical amplification is performed by the doped fiber 2, the main signal and the pump light are separated by the splitter 3, and only the main signal is output. On the other hand, in the optical coupler 4, an electric signal photoelectrically converted according to the light amount of the current excitation light source 5 is input to the monitoring circuit 7 and monitors the optical output power of the excitation light source 5. When the input electric signal falls below a preset threshold voltage (for example, a voltage corresponding to 1/2 of the initial optical output power), the monitoring circuit 7 switches the second pumping light source 6 from non-operation to operation. The switching operation of the first and second excitation light sources 5 and 6 is automatically performed so that one excitation light source 5 is changed from operation to non-operation.

In this way, when the monitoring circuit 7 reduces the optical output of the working first excitation light source to a preset optical output, it is possible to automatically switch to the spare second excitation light source.

FIG. 1B is a block diagram of a second embodiment of the present invention.
FIG. 3 and FIG. 3 are diagrams for explaining the operation of the second embodiment.

In the second embodiment, the first and second pumping light sources 5 and 6 are simultaneously operating, and the optical powers of P ₁ and P ₂ are respectively supplied by the optical coupler 4a with the bias current of B1 shown in FIG. and radiates to the first P ₀ becomes light power at the output of the optical coupler 4a is input to the multiplexer 1, performs optical amplification through Er doped fiber 2 to the main signal and the combined coupling. The demultiplexer 3 separates the light of the main signal and the pump light from the output light of the Er-doped fiber 2, and outputs only the main signal.

On the other hand, the second output of the optical coupler 4 is for monitoring the first output power P ₀ , is connected to the automatic output power control (APC) circuit 8, and the APC circuit 8 controls the optical power of the excitation light sources 5 and 6. It has a function of simultaneously controlling the bias currents of the excitation light sources 5 and 6 so that the sum is constant. Now, as shown in FIG. 3, if the bias-light output characteristic of the pump light source 6 is deteriorated, the APC circuit 8 performs a control operation on the pump light sources 5 and 6 so as to increase the bias current ΔB. Bias current of the excitation light sources 6, 6 is increased by ΔB from B1 to B2, the respective optical power P _'1, P' outputs of the ₂ next optical coupler 4a, initial set power P _0, and the excitation light source 5 , 6 does not change,
Optical amplification with a constant gain can be performed.

〔The invention's effect〕

As described above, according to the present invention, the life of the optical amplifier can be extended by using a plurality of pumping light sources indispensable to the optical amplifier using the doped fiber and switching between the working pumping light source and the spare pumping light source.

Further, by operating with the sum of the optical powers from a plurality of pump light sources, there is an effect that a code error of the main signal can be prevented.

[Brief description of the drawings]

FIGS. 1A and 1B are block diagrams of the first and second embodiments of the present invention, FIGS. 2 and 3 are diagrams for explaining the operation of the second embodiment, and FIGS. FIG. 1 is a block diagram of an example of a conventional optical amplification repeater. 1 ... combiner, 2 ... Er doped fiber, 3 ... demultiplexer, 4,4a ... optical coupler, 5,6 ... excitation light source, 7 ... monitoring circuit, 8 ... APC circuit .

Claims (2)

(57) [Claims] A first excitation light source for emitting a first optical power, a second excitation light source for emitting a second optical power, and a light amount of the input first or second optical power. An optical coupler that outputs an electric signal that has been photoelectrically converted by the optical coupler; a multiplexer that multiplexes the first or second optical power from the optical coupler and a main signal of light to be relayed; A doped fiber for optically amplifying an output from the wave filter; and a first fiber for driving when the electric signal falls below a predetermined threshold.
And a monitoring circuit for switching the second excitation light source. 2. A plurality of excitation light sources for radiating optical power, an optical coupler for outputting an electric signal photoelectrically converted in accordance with a sum of photoelectrics from the plurality of optical powers, and an optical coupler from the optical coupler. A multiplexer for multiplexing the sum of the optical power and the main signal of the light to be relayed, and a doped fiber for optically amplifying an output from the multiplexer so that the electric signal is set to a reference value set in advance. An optical amplifying repeater comprising: an automatic power adjustment circuit for driving the plurality of excitation light sources.