US 6,445,720 B1Granted

Optical output level control device for an optical wavelength multiplexer included in an optical transmission system

AssigneeOki Electric Industry Co., Ltd.

InventorToshiaki Mukojima

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Abstract

In an optical transmission system, an optical output control device for an optical wavelength multiplexer includes a wavelength generation circuit for generating wavelength data representative of a wavelength λ1 or λ2 and implemented by a decimal number or a binary number. A wavelength administrative byte generation circuit receives the λ1 or λ2 wavelength data and transfers it to a wavelength administrative byte insertion circuit and a wavelength administrative byte detection circuit. The wavelength administrative byte insertion circuit inserts the λ1 or λ2 wavelength data in the positions of bytes D1 and D2 of a high-speed signal, transforms the resulting multiplex signal to a corresponding optical signal, and delivers the optical signal to an optical multiplexing circuit. The multiplexing circuit multiplexes high-speed optical signals respectively having the wavelengths λ1 and λ2 and feeds the resulting multiplex high-speed optical signal to an optical amplifier. On the other hand, the wavelength administrative byte detecting circuit detects the data λ1 and data λ2 and sends them to a wavelength counting circuit. The wavelength counting circuit counts the different wavelengths and feeds its count to a light source control circuit. The light source control circuit generates a control signal based on the count and feeds it to an exciting light source. The exciting light source applies to the optical amplifier an exciting optical signal whose intensity is determined by the control signal. The amplifier combines the high-speed optical signal and exciting optical signal and then amplifies signal light contained in the combined signal to a preselected level.

Claims18

Dependent claims

In an optical output control device for an optical wavelength multiplexer included in an optical transmission system including at least a first and a second multiplexer and a first optical wavelength multiplexer situated at a transmitting station, said first multiplexer comprising:

a first multiplexing circuit for transforming a plurality of preselected low-speed optical signals input thereto to corresponding electric signals, and multiplexing said electric signals to thereby output a first high-speed signal;
and
a first transmitting circuit for receiving the first high-speed signal from said first multiplexing circuit, generating first wavelength data representative of a wavelength of light output from said first multiplexer, inserting said first wavelength data at a preselected position of said first high-speed signal, and transforming said first high-speed signal with said first wavelength data to a first high-speed optical signal having a first wavelength;
said second multiplexer comprising:
a second multiplexing circuit for transforming a plurality of preselected low-speed optical signals input thereto to corresponding electric signals, and multiplexing said electric signals to thereby output a second high-speed signal;
and
a second transmitting circuit for receiving the second high-speed signal from said second multiplexing circuit, generating second wavelength data representative of a wavelength of light output from said second multiplexer, inserting said second wavelength data at a preselected position of said second high-speed signal, and transforming said second high-speed signal with said second wavelength data to a second high-speed optical signal having a second wavelength;
said first optical wavelength multiplexer comprising:
a first wavelength multiplexing circuit for multiplexing the wavelength of the first high-speed optical signal and the wavelength of the second high-speed optical signal;
and
a first control light amplifying circuit for receiving a high-speed optical signal from said first wavelength multiplexing circuit, receiving the first wavelength data from said first transmitting circuit, receiving the second wavelength data from said second transmitting circuit, counting different wavelengths on the basis of said first wavelength data and said second wavelength data, and amplifying said high-speed optical signal with an exciting optical signal whose intensity is determined by a control signal based on a number of wavelengths counted.

8 more elements

a first multiplexing circuit for transforming a plurality of preselected low-speed signals input thereto to corresponding electric signals, and multiplexing said electric signals to thereby form a first high-speed signal;
and
a first transmitting circuit for receiving the first high-speed signal from said first multiplexing circuit, generating first optical output data representative of an optical output power value output from said first multiplexer, inserting said first optical output data at a preselected position of said first high-speed signal, and transforming said first high-speed signal with said first output power data to a first high-speed optical signal having a first wavelength;
said second multiplexer comprising:
a second multiplexing circuit for transforming a plurality of preselected low-speed optical signals input thereto to corresponding electric signals, and multiplexing said electric signals to thereby form a second high-speed signal;
and
a second transmitting circuit for receiving the second high-speed signal from said second multiplexing circuit, generating second optical output data representative of an optical output power value output from said second multiplexer, inserting said second optical output data at a preselected position of said second high-speed signal, and transforming said second high-speed signal with said second output power data to a second high-speed optical signal having a second wavelength;
said first optical wavelength multiplexer comprising:
a first optical level control circuit for measuring a difference in level between the first optical output data and the second optical output data respectively received from said first transmitting circuit and said second transmitting circuit, and generating a first and a second control signal based on said difference;
a first optical variable attenuator for variably attenuating the first high-seed signal received from said first transmitting circuit in accordance with the first control signal received from said first optical level control circuit;
a second optical variable attenuator for variably attenuating the second high-seed signal received from said second transmitting circuit in accordance with the second control signal received from said first optical level control circuit;
a first wavelength multiplexing circuit for multiplexing said first high-speed optical signal and said second high-speed optical signal respectively output from said first optical variable attenuator and said second optical variable attenuator with respect to wavelength;
and
a first control light amplifying circuit for amplifying a high-speed optical signal output from said first wavelength multiplexing circuit with an exciting optical signal whose intensity is determined by a third control signal.

11 more elements

a first multiplexing circuit for transforming a plurality of preselected low-speed optical signals input thereto to corresponding electric signals, and multiplexing said electric signals to thereby output a first high-speed signal;
and
a first transmitting circuit for receiving the first high-speed signal from said first multiplexing circuit, generating first optical output data representative of an optical output power value output from said first multiplexer, inserting said first optical output data at a preselected position of said first high-speed signal, and transforming said first high-speed signal with said first output power data to a first high-speed optical signal having a first wavelength;
said second multiplexer comprising:
a second multiplexing circuit for transforming a plurality of preselected low-speed optical signals input thereto to corresponding electric signals, and multiplexing said electric signals to thereby output a second high-speed signal;
and
a second transmitting circuit for receiving the second high-speed signal from said second multiplexing circuit, generating second optical output data representative of an optical output power value output from said second multiplexer, inserting said second optical output data at a preselected position of said second high-speed signal, and transforming said second high-speed signal with said second output power data to a second high-speed optical signal having a second wavelength;
said first optical wavelength multiplexer comprising:
a first optical level control circuit for measuring a difference in level between the first optical output data and the second optical output data respectively received from said first transmitting circuit and said second transmitting circuit, and generating a first and a second control signal based on said difference;
a first wavelength multiplexing circuit for multiplexing the first high-speed optical signal and the second high-speed optical signal respectively received from said first transmitting circuit and said second transmitting circuit with respect to wavelength;
a first control light amplifying circuit for amplifying a high-speed optical signal received from said first wavelength multiplexing circuit with an exciting optical signal whose intensity is determined by a third control signal;
a first optical demultiplexing circuit for demultiplexing a high-speed optical signal output from said first control light amplifying circuit into a first and a second high speed optical signal respectively corresponding to the first wavelength and the second wavelength;
a first variable optical attenuator for variably attenuating the first high-speed optical signal output from said first optical demultiplexing circuit in accordance with the first control signal output from said first optical level control circuit;
a second variable optical attenuator for variably attenuating the second high-speed optical signal output from said first optical demultiplexing circuit in accordance with the second control signal output from said first optical level control circuit;
and
a second wavelength multiplexing circuit for multiplexing the first high-speed signal and the second high-speed signal respectively output from said first optical variable attenuator and said second optical variable attenuator.

13 more elements

Dependencies are inferred from the claim text.