Optical channel regulator and method

• US 6,157,475 A
• Filed: 12/16/1998
• Issued: 12/05/2000
• Est. Priority Date: 09/30/1998
• Status: Expired due to Fees

• Current Assignee: Alcatel SA (Nokia Corporation)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Maxham, Kenneth Y., Dugan, J. Michael
• Primary Examiner(s): NEGASH, KINFE MICHAEL
• Application Number:
  US09/212,972
• Time in Patent Office: 720 Days
• Field of Search: 359/110, 359/124, 359/133, 359/187, 385/140
• US Class Current: 398/26
• CPC Class Codes: H04B 10/25073 using spectral equalisation, e.g. spectral filtering
• CPC Class Codes: H04B 10/2971 A single amplifier for both directions
• CPC Class Codes: H04J 14/0221 Power control, e.g. to keep the total optical power constant
• CPC Class Codes: H04J 14/02216 by gain equalization

Abstract

An optical channel regulator (46) is provided. The optical channel regulator (46) includes a tapped optical coupler (60) receiving an optical line carrying an optical signal. The tapped optical coupler (60) provides substantially all of the optical signal as an output. An electrically variable optical attenuator (64) receives the output of the tapped optical coupler (60) and attenuates the optical signal responsive to a feedback control signal. A second tapped optical coupler (66) receives an output of the attenuator (64). The second coupler (66) provides substantially all of the received optical signal as an output and provides a remaining portion of the optical signal as a tapped output. An optical detector (68) then receives the tapped output and provides an output signal representing the optical signal. A comparator (70) receives the output signal of the optical detector (68) and a reference signal. The comparator (70) compares the output signal and the reference signal and provides the feedback control signal to the attenuator (64) responsive to the comparison. As part of a multi-channel communication system, the regulator is used to adjust the levels of each channel for automatically maintaining channel balance and equalization.

Claims

1. A method for regulating an optical channel, comprising;

receiving an optical signal;

attenuating the optical signal responsive to a feedback control signal to provide an attenuated optical signal;

tapping a portion of the attenuated optical signal to produce an attenuated optical signal as an output;

providing an untapped portion of the attenuated optical signal as an output optical signal;

outputting the attenuated optical signal output;

comparing an optical signal-to-noise ratio of the attenuated optical signal to a reference signal at the receiving end of the transmission; and

generating a feedback control signal responsive to the comparing of the optical signal-to-noise ratio.

2. The method in claim 1 further comprising:

tapping the attenuated optical signal; and

generating the feedback control signal in response to the monitoring of the attenuated optical signal.

3. A system for regulating optical channels comprising:

a plurality of optical input channels operable to transport an optical signal;

a plurality of optical attenuators, operable to;

receive said optical signal from each of said plurality of optical input channels;

attenuate said optical signal responsive to a feedback control signal; and

output an attenuated optical signal;

a plurality of transmission channels operable to transport the attenuated optical signal from each of said plurality of optical attenuators;

a plurality of optical monitors operable to;

receive the attenuated optical signal from each of the plurality of transmission channels;

provide substantially all of the attenuated optical signal as an output; and

provide a control signal in response to a remaining portion of the attenuated optical signal;

a first microprocessor, operable to;

receive the control signal from each of the plurality of optical monitors;

optimize all of the attenuated optical signals in response to the control signal from each of the plurality of optical monitors; and

generate a plurality of feedback control signals in response to the optimizing of the attenuated signals to each of the plurality of optical attenuators.

4. The system of claim 3, wherein the optical monitor is further operable to:

track an optical signal-to-noise ratio of each of the attenuated optical signals;

provide a control signal responsive to the signal-to-noise ratio; and

wherein the first microprocessor is further operable to;

optimize all of the attenuated optical signals responsive to the signal-to-noise ratio of each of the attenuated optical signals; and

generate the plurality of feedback control signals.

5. The system of claim 3, wherein each of the plurality of optical monitor is further operable to:

monitor the power of the attenuated optical signal;

provide a control signal responsive to the power of the attenuated optical signal; and

wherein the first microprocessor is further operable to;

optimize all of the attenuated optical signals responsive to the power of each the attenuated optical signal; and

generate a plurality of feedback control signals responsive to the optimizing of the attenuated signals.

6. The system of claim 5, wherein each of the plurality of optical monitors is further operable to:

monitor each of the optical signals on the plurality of transmission channels at any point along each transmission channel; and

generate a control signal responsive to the monitoring of the optical signals.

7. The system of claim 5, wherein each of the plurality of optical monitors is further operable to:

monitor each of the optical signals on the plurality of transmission channels at multiple points along each transmission channel; and

generate a control signal responsive to the monitoring of the optical signals.

8. The system of claim 3, wherein the plurality of transmission channels further comprise:

an optical combiner, operable to;

receive the attenuated signals from each of the plurality of optical attenuators;

combine the attenuated signals from each of the plurality of optical attenuators into a combined signal; and

output the combined signal;

at least one optical amplifier operable to amplify the combined signal; and

an optical demultiplexer operable to;

receive the combined signal;

demultiplex the combined signal; and

output each of the attenuated optical signals.

9. The system of claim 5, further comprising:

a second microprocessor operable to;

receive each of the control signals from each of the plurality of optical monitors;

generate a response signal responsive to each of the control signals; and

output the control signal;

a data communication link operable to;

connect the second microprocessor with the second microprocessor; and

transport the response signal;

and wherein the first microprocessor is further operable to;

receive the response signal; and

optimize all of the attenuated optical signals responsive to the response signal from the second microprocessor.

10. The system of claim 3, wherein the first microprocessor is further operable to optimize all of the attenuated optical signals according to a preprogrammed software optimization routine.

11. The system of claim 3, wherein the first microprocessor is further operable to optimize all of the attenuated optical signals according to manual inputs by an operator.