JPH0437729A - Optical amplifying repeater - Google Patents

Abstract

PURPOSE:To prolong the life of an optical amplifier by using plural exciting light sources which are essential for by using plural exciting light sources which are essential for the optical amplifier using a doped fiber and switching an in-use and a stand-by exciting light source. CONSTITUTION:The output of a multiplexer 1 is amplified optically by the Er-doped fiber 2 and then separated by a demultiplexer 3 into a main signal and exciting light, and only the main siganl is outputted. An electric signal which is converted photoelectrically according to the quantity of light of the in-use exicting light source 5 is inputted to a monitor circuit 7 and an optical coupler 4 monitors the light output electric power of the exciting light source 5. A monitor circuit 7 switches the 1st and 2nd exciting light sources 5 and 6 automatically when the input electric signal drops below a previously set threshold voltage so that the 2nd exicting light source 6 is turned on and the 1st exciting light source 5 is turned off. Consequently, the monitor circuit 7 switches the 1st exciting light source in use automatically to the 2nd stand-by exciting light source when the light output of the 1st exciting light source decreases to the preset light output.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical amplifying repeater, and more particularly to an optical amplifying repeater using a doped fiber for amplifying a main optical signal.

[Conventional technology]

Conventionally, this type of optical amplifying repeater connects the output of a pumping light source 15 that excites the main optical signal to the second input of the multiplexer 11, as shown in FIG. 1, the output of the multiplexer 11 is optically amplified through the Er-doped fiber 12, and the pumping light is blocked by the demultiplexer 13. It consisted of one excitation light source 15 with a high optical output necessary for this purpose.

[Problem to be solved by the invention]

In the conventional optical amplification repeater described above, when the optical output power of the high optical output pumping light source necessary for optical amplification decreases, the optical amplification characteristics deteriorate.

In addition, pump light sources are required to be compact and have a long lifespan, which conflict with high optical output characteristics. Since the side is used as a cold standby, it has the disadvantage that it gives a code error to the main line system when switching from the current pumping light source to the standby pumping light source.

[Means to solve the problem]

A first optical amplification repeater of the present invention includes a first pumping light source that emits a first optical power, a second pumping light source that emits a second optical power, and a second pumping light source that emits a second optical power. an optical coupler that outputs an electrical signal photoelectrically converted according to the amount of light of the optical power; and an optical coupler that combines and outputs the first or second optical power from the optical coupler and the main signal of the light to be relayed. A multiplexer, a doped fiber for optically amplifying the output of the multiplexer, and switching between the first and second excitation light sources to be driven when the electrical signal falls below a preset threshold. It has a monitoring circuit.

The optical amplification repeater according to the second aspect of the present invention includes a plurality of excitation light sources that radiate optical power, an optical coupler that outputs a photoelectrically converted electric signal according to the sum of photoelectric power from the plurality of optical powers, A multiplexer that multiplexes the sum of the optical power from the optical coupler and the main signal of the light to be relayed, a doped fiber that optically amplifies the output from this multiplexer, and the electrical signal is set in advance. and an automatic power adjustment circuit that drives the plurality of excitation light sources so as to achieve the set reference value.

〔Example〕

Next, the present invention will be explained 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 excitation light source 5 is on the active side and the second excitation light source 6 is on the standby side, and normally only the excitation light source 5 on the active side is operating. The optical output of the excitation light source 5 is input to the optical coupler 4, and the excitation light from the photovoltaic device 4 is input to the multiplexer 1 together with the main signal to be relayed and multiplexed. The output from multiplexer 1 is Er
After optical amplification is performed by the doped fiber 2, the main signal and pump light are separated by the demultiplexer 3, and only the main signal is output. On the other hand, the optical coupler 4 outputs a photoelectrically converted electrical signal according to the light intensity of the current excitation light source 5 to the monitoring circuit F! @7, and monitors the optical output power of the excitation light source 5. When the input electrical signal falls below a preset threshold voltage (for example, a voltage corresponding to 172 of the initial optical output power), the monitoring circuit 7 switches the second excitation light source 6 from non-operating to operating. The switching operation between the first and second excitation light sources 5, 6 is automatically performed so that the first excitation light source 5 goes from operating to inactive.

If the second method is adopted, the monitoring circuit 7 can automatically switch to the backup second pumping light source when the optical output of the currently used first pumping light source decreases to a preset optical output.

FIG. 1B is a block diagram of a second embodiment of the present invention, and FIGS. 2 and 3 are diagrams for explaining the operation of the second embodiment.

In the second embodiment, the first and second pumping light sources 5.6 are simultaneously in the wrong operating state and transmit optical powers p, , p2, respectively, to the optical coupler 4a with a bias current of Bl shown in FIG. P at the first output point of the optical coupling gy 4 a. The optical power of E
Optical amplification is performed through the r-doped fiber 2. Duplexer 3
separates the main signal light and excitation 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 used for monitoring the second output power Po, and is connected to an automatic output power control (APC) circuit 8, which controls the optical power of the excitation light source 5.6. It has a function of simultaneously controlling the bias currents of the excitation light sources 5 and 6 so that the sum of the values is constant. Now, if the bias-light output characteristic of the pumping light source 6 has deteriorated as shown in FIG. 3, the APC circuit 8 performs a control operation to increase the bias current ΔB for the pumping light source 5.6.

The bias current of the excitation light source 6.6 is from B1 to 82/\ΔB
The optical power of each optical power becomes P'1°P'2, and the output of the optical coupler 4a becomes the initially set power Po, and the power phase from the excitation light sources 5 and 6 does not change, and the output power is constant gain. Can perform optical amplification.

〔Effect of the invention〕

As explained above, the present invention aims to extend the life of an optical amplifier by using a plurality of pumping light sources essential for an optical amplifier using a doped fiber and switching between the active and backup pumping light sources. I can do it.

Further, by operating with the sum of optical power from a plurality of excitation light sources, there is an effect that code errors in the main signal can be prevented.

source, 7...Monitoring circuit, 8...APC circuit.

Claims (1)

[Claims] 1. A first excitation light source that emits a first optical power, a second excitation light source that emits a second optical power, and an input of the first or second optical power; an optical coupler that outputs an electrical signal photoelectrically converted according to the amount of light, and a multiplexer that multiplexes and outputs the first or second optical power from the optical coupler and the main signal of the light to be relayed. , a doped fiber that optically amplifies the output from the multiplexer, and a monitoring circuit that switches between the first and second pumping light sources to be driven when the electrical signal drops below a preset threshold. An optical amplification repeater comprising: 2. A plurality of excitation light sources that emit optical power, an optical coupler that outputs an electrical signal photoelectrically converted according to the sum of photoelectric power from the plurality of optical powers, and a plurality of excitation light sources that emit optical power from the optical coupler. a multiplexer for multiplexing the sum and the main signal of the light to be relayed; a doped fiber for optically amplifying the output from the multiplexer; An automatic power adjustment circuit for driving a pumping light source.