This application provides a sending device, a receiving device, an optical transmission system, and an optical power control method. The sending device includes a multiplexing unit and an optical power adjustment unit. The multiplexing unit is configured to send at least two communication optical waves to a fiber channel, and is further configured to send or receive at least two detection optical waves through the fiber channel. The optical power adjustment unit is configured to: obtain a power control instruction, where the power control instruction is generated according to power change information between the at least two detection optical waves. The optical power adjustment unit is further configured to perform optical power amplification and/or attenuation on at least one communication optical wave in the at least two communication optical waves according to the power control instruction.

Systems and methods include, for operation on an optical fiber in an optical network with the optical fiber having extended optical spectrum that include a plurality of bands including at least the C-band and one or more additional bands, segmenting the plurality of bands by distance based on different transmission specifications for the plurality of bands based on fiber types and amplifiers used for corresponding bands; and placing one or more channels on the optical fiber in a corresponding band of the plurality of bands based on a distance between nodes associated with each of the one or more channels. The segmenting is based on a metric that is a function of fiber type of the optical fiber and amplifier performance for amplifiers used in the plurality of bands.

Systems and methods include, for operation on an optical fiber in an optical network with the optical fiber having extended optical spectrum that include a plurality of bands including at least the C-band and one or more additional bands, segmenting the plurality of bands by distance based on different transmission specifications for the plurality of bands based on fiber types and amplifiers used for corresponding bands; and placing one or more channels on the optical fiber in a corresponding band of the plurality of bands based on a distance between nodes associated with each of the one or more channels. The segmenting is based on a metric that is a function of fiber type of the optical fiber and amplifier performance for amplifiers used in the plurality of bands.

There is provided a method and apparatus for evaluating nonlinear impairment of an optical fiber link. The method includes partitioning a natural span of the optical fiber link into multiple sub-spans, each of the multiple sub-spans determined based on chromatic dispersion (CD) equivalence; The method further includes for each of the multiple sub-spans, acquiring sub-span function parameters and a sub-span input power indicative of input power at a particular sub-span, the sub-span function parameters including noise variance and correlations between the particular sub-span and others of the multiple sub-spans. The method additionally includes determining the nonlinear impairment of the optical fiber link based on the sub-span input power and the sub-span function parameters acquired for each of the multiple sub-spans.

There is provided a method and apparatus for evaluating nonlinear impairment of an optical fiber link. The method includes partitioning a natural span of the optical fiber link into multiple sub-spans, each of the multiple sub-spans determined based on chromatic dispersion (CD) equivalence; The method further includes for each of the multiple sub-spans, acquiring sub-span function parameters and a sub-span input power indicative of input power at a particular sub-span, the sub-span function parameters including noise variance and correlations between the particular sub-span and others of the multiple sub-spans. The method additionally includes determining the nonlinear impairment of the optical fiber link based on the sub-span input power and the sub-span function parameters acquired for each of the multiple sub-spans.

Aspects of the present disclosure describe methods for reducing guided acoustic wave Brillouin (GAWBS) noise in an optical fiber that may be included in an optical communications system by reducing the polarization diffusion length of the fiber by increasing the birefringence of the optical fiber, the increased birefringence of the optical fiber being increased with respect to its average magnitude. Additionally, the polarization diffusion length is reduced by reducing the coherence length of birefringence of the optical fiber.

Disclosed herein are methods and systems for configuring a spectral loading pattern for a transmission line segment in an optical network, the method comprising obtaining at least one loading policy, activating at least one of the at least one loading policy, receiving a plurality of requested operations, obtaining one or more static datapoint and one or more dynamic datapoint associated with the transmission line segment, obtaining loading parameters and one or more loading algorithm from the at least one activated loading policy, generating a loading response according to the one or more loading algorithm, and changing a spectral loading pattern of the transmission line segment based on the loading response. The requested operations may identify operations to be executed in either of a current cycle or one or more subsequent cycle. The loading response may identify a subset of the operations to be executed in the current cycle.

Disclosed herein are methods and systems for configuring a spectral loading pattern for a transmission line segment in an optical network, the method comprising obtaining at least one loading policy, activating at least one of the at least one loading policy, receiving a plurality of requested operations, obtaining one or more static datapoint and one or more dynamic datapoint associated with the transmission line segment, obtaining loading parameters and one or more loading algorithm from the at least one activated loading policy, generating a loading response according to the one or more loading algorithm, and changing a spectral loading pattern of the transmission line segment based on the loading response. The requested operations may identify operations to be executed in either of a current cycle or one or more subsequent cycle. The loading response may identify a subset of the operations to be executed in the current cycle.

A method for determining an optical signal power change, wherein the method includes: A first optical signal that includes a plurality of wavelength signals is obtained, where the plurality of wavelength signals are distributed in a plurality of bands. Then, an optical power of each band and a center wavelength signal of each band are detected, and a preset single-wavelength transmit power and a preset coefficient are obtained. Next, an equivalent quantity N of equivalent wavelength signals is determined, and an equivalent wavelength signal corresponding to the first optical signal is determined. Further, a target power that is used to compensate for a first power change value of the first optical signal in transmission over an optical fiber is determined based on the preset coefficient, the equivalent wavelength signal, the equivalent quantity, and the preset single-wavelength transmit power.

A method for determining an optical signal power change, wherein the method includes: A first optical signal that includes a plurality of wavelength signals is obtained, where the plurality of wavelength signals are distributed in a plurality of bands. Then, an optical power of each band and a center wavelength signal of each band are detected, and a preset single-wavelength transmit power and a preset coefficient are obtained. Next, an equivalent quantity N of equivalent wavelength signals is determined, and an equivalent wavelength signal corresponding to the first optical signal is determined. Further, a target power that is used to compensate for a first power change value of the first optical signal in transmission over an optical fiber is determined based on the preset coefficient, the equivalent wavelength signal, the equivalent quantity, and the preset single-wavelength transmit power.