US 6,959,149 B2 · Power balancing in DWDM optical networks

Abstract

The invention provides a method of balancing the power level of an optical signal within an aggregate of optical signals in an amplified dense wavelength division multiplexing DWDM optical network, as well as power balancing apparatus therefor. The method involves measuring the power level of the optical signal received at an optical receiver through the optical link and referencing said measured receive power level to a nominal power level in the multiplex immediately preceding the receiver; measuring the power level of the optical signal at an optical transmitter and referencing said measured transmit power level to a nominal power level in the multiplex immediately following the transmitter; calculating a mean power level of the optical signal from said optical measurements, the mean power level of the optical signal being the mean of the power levels of the optical signal at the transmitter and at the receiver referenced to the nominal power levels in the associated multiplexes; and adjusting the mean power level of the optical signal independently of the power levels of other optical signals carried on the same optical link to the receiver so that a desired OSNR at the receiver is achievable.

Claims20

Dependent claims

A method of balancing the power level of an optical signal within an aggregate of optical signals in an amplified dense wavelength division multiplexing DWDM optical network having an optical link extending between an optical signal transmitter and an optical signal receiver, said optical signal transmitter associated with a multiplexer following it on along said optical link, said optical signal receiver associated with a multiplexer preceding it along said optical link, said optical link having one or more optical fibers spans, some of the optical fiber spans having an optical amplifier and variable optical attenuator VOA, said method comprising:

measuring the power level of the optical signal received at the receiver through the optical link and referencing said measured receive power level to a nominal power level in the multiplexer immediately preceding the receiver;
measuring the power level of the optical signal at the optical transmitter and referencing said measured transmit power level to a nominal power level in the multiplexer immediately following the transmitter;
calculating a mean power level of the optical signal from said optical measurements, the mean power level of the optical signal being the mean of the power levels of the optical signal at the transmitter and at the receiver referenced to the nominal power levels in the associated multiplexers;
and
adjusting the mean power level of the optical signal independently of the power levels of other optical signals carried on the same optical link to the receiver so that a desired OSNR at the receiver is achievable.

2 more elements

Power balancing apparatus for balancing the power level of an optical signal within an aggregate of optical signals in an amplified dense wavelength division multiplexing DWDM optical network having an optical link extending between an optical signal transmitter and an optical signal receiver, said optical signal transmitter associated with a multiplexer following it on along said optical link, said optical signal receiver associated with a multiplexer preceding it along said optical link, said optical link having one or more optical fibers spans, some of the optical fiber spans having an optical amplifier and variable optical attenuator VOA, said apparatus comprising:

a first-order closed mean power control loop extending between the receiver and the transmitter, said control loop operable to calculate a mean power level of the optical signal and to adjust the mean power level of said optical signal so that a desired OSNR for said optical signal at the receiver is achieved, the mean power level being the mean of the power levels of said optical signal at the transmitter and at the receiver referenced to the nominal power levels in the associated multiplexers.

An optical communications system comprising:

a dense wavelength division multiplexing DWDM optical network having an optical link extending between an optical signal transmitter and an optical signal receiver, said optical signal transmitter associated with a multiplex following it on along said optical link, said optical signal receiver associated with a multiplexer preceding it along said optical link, said optical link having one or more optical fibers spans, some of the optical fiber spans having an optical amplifier and variable optical attenuator VOA;
and
a first-order closed mean power control loop extending between the receiver and the transmitter, said control loop operable to calculate a mean power level of the optical signal and to adjust the mean power level of said optical signal so that a desired OSNR for said optical signal at the receiver is achieved, the mean power level being the mean of the power levels of said optical signal at the transmitter and at the receiver referenced to the nominal power levels in the associated multiplexers.

A computer readable storage medium storing instructions that, when executed by a computer, cause the computer to perform a method of balancing the power level of an optical signal within an aggregate of optical signals in an amplified dense wavelength division multiplexing DWDM optical network having an optical link extending between an optical signal transmitter and an optical signal receiver, said optical signal transmitter associated with a multiplexer following it on along said optical link, said optical signal receiver associated with a multiplexer preceding it along said optical link, said optical link having one or more optical fibers spans, some of the optical fiber spans having an optical amplifier and variable optical attenuator VOA, said method comprising:

measuring the power level of the optical signal received at the receiver through the optical link and referencing said measured receive power level to a nominal power level in the multiplexer immediately preceding the receiver;
measuring the power level of the optical signal at the optical transmitter and referencing said measured transmit power level to a nominal power level in the multiplexer immediately following the transmitter;
calculating a mean power level of the optical signal from said optical measurements, the mean power level of the optical signal being the mean of the power levels of the optical signal at the transmitter and at the receiver referenced to the nominal power levels in the associated multiplexers;
and
adjusting the mean power level of the optical signal independently of the power levels of other optical signals carried on the same optical link to the receiver so that a desired OSNR at the receiver is achievable.

2 more elements

Dependencies are inferred from the claim text.

Power balancing in DWDM optical networks

Life of this patent

Power balancing in DWDM optical networks

Life of this patent

Abstract

Claims20