An optical communication amplification system may include a number of amplification stages for an optical signal that includes a first optical wavelength band signal portion and a second optical wavelength band signal portion. Each amplification stage may separate the first optical wavelength band signal portion from the second optical wavelength band signal portion. The separated first optical wavelength band signal portion is amplified using one or more first optical wavelength band amplifiers and the separated second optical wavelength band signal portion are amplified using one or more second optical wavelength band amplifiers. The amplified first optical wavelength band signal portion is filtered and a reflected portion of the first optical wavelength band signal portion may be used to provide energy to the one or more second optical wavelength band amplifiers to increase the power or gain of the separated second optical wavelength band signal portion.

An optical amplifier includes: an optical amplifying fiber; and a pump light source that supplies pump light to the optical amplifying fiber, the pump light being used for parametrically amplifying signal light input to the optical amplifying fiber by using a non-linear optical effect of the optical amplifying fiber. The fluctuation of the zero-dispersion wavelength of the optical amplifying fiber in the longitudinal direction is within the limit of 0.5 nm/100 m.

An optical carrier selector system is provided for selecting a wanted carrier signal from a multi-carrier signal comprising a plurality of carrier signals. The optical carrier selector system comprises a series of optical filter devices. Each optical filter device of the series comprises an input port for receiving a signal comprising two or more carrier signals, each optical filter device being configured to filter out an unwanted carrier signal. Each optical filter device also comprises an output port for outputting at least the wanted carrier signal and any remaining signals that have not been filtered out by that particular optical filter device, and a drop port for outputting the unwanted carrier signal that is being filtered out by the respective optical filter device. By outputting from a drop port the unwanted carrier signal that is being filtered out by the respective optical filter device, this has the advantage of enabling the operation of the optical carrier selector system to be monitored for proper operation, and controlled or adjusted if necessary.

A communication system includes a first optical system and a second optical system optically connected to a clamping laser and a pump laser. The first optical system includes first and second optical splitters. The first optical splitter is configured to receive a clamping laser signal from the clamping laser and split the signal into split clamping laser signals. The second optical splitter is configured to receive a pump laser signal from the pump laser and split signal into split pump laser signals. The second optical system is optically connected to the first optical system and includes amplifier systems. Each amplifier system is configured to receive a multiplexed signal. The second optical system includes first and second combiners optically connected to an erbium-doped fiber. The first combiner is optically connected to the first splitter, and the second combiner is optically connected to the second splitter.

Aspects of the disclosure provide systems and methods which avoid the negative effects of Spectral Hole Burning when spectral changes are made for an optical communication system (OCS). Embodiments of the disclosure are directed to methods and systems which preform spectral holes for the range of wavelength channels expected to be used in the OCS. Embodiments include a configurable idle tone source for providing power to each of a set of idle tone wavelengths distributed across the spectral band used in the optical communication system. The configurable idle tone source is communicatively coupled to an output fiber of an optical network element and controlled such that optical power is present in the output optical fiber at each one of the set of idle tone wavelengths.

An apparatus includes an optical wavelength multiplexer to multiplex a sequence of optical wavelength channels. The optical wavelength multiplexer comprises a first passive optical filter to combine odd channels of the sequence of optical wavelength channels into a first multiplexed optical signal, a second passive optical filter to combine even channels of the sequence of optical wavelength channels into a second multiplexed optical signal, and an optical combiner to combine the odd channels and the even channels into a composite optical signal. The optical wavelength multiplexer comprises variable optical attenuators, and an electronic controller to operate the variable optical attenuators to substantially block one or more adjacent optical wavelength channels adjacent to a particular optical wavelength channel provisioned to the optical wavelength multiplexer in response to a width for the particular optical wavelength channel being larger than a width of the adjacent optical wavelength channel(s).

Provided is a method for reducing the impact of transient effects in an optical network. The optical network includes at least one span, and an optical signal having a plurality of sub-bands travels through at least one span of the at least one span of the optical network. Each of the at least one span has associated amplifiers and the associated amplifiers are connected to launch optical signals into a remainder of a corresponding optical transmission line. Respectively one of the sub-bands of the optical signal traveling through the span is amplified by one of these associated amplifiers. Each of the associated amplifiers includes at least one control element for controlling gain and tilt of the corresponding amplifier. The method includes the steps of for each span, acquiring an actual value of at least one performance parameter; for each span, respectively computing actual settings for each of the control elements included in the amplifiers associated to the corresponding span based on the actual value of the at least one performance parameter of the corresponding span; and for each span, respectively adjusting the settings of each of the control elements included in the amplifiers associated to the corresponding span based on the computed actual settings for the corresponding control element, in order to reduce the impact of transient effects.

An optical add-drop multiplexer and a branching unit are provided, where implementation of the optical add-drop multiplexer includes: an optical processing component, a first combining device, a second combining device, and a second scrambler, where the optical processing component includes an input end, a first output end, a second output end, and a third output end; the first output end of the optical processing component is connected to a first input end of the second combining device, and the second output end of the optical processing component is connected an input end of the second scrambler; an output end of the second scrambler is connected to a second input end of the second combining device; and the third output end of the optical processing component is connected to a first input end of the first combining device.

An optical transmission apparatus includes a variable attenuator configured to adjust output intensity of each wavelength signal included in a multiplexed optical signal having been input; a monitor configured to measure an output spectrum of the variable attenuator; a calculation unit configured to calculate an amount of spectral narrowing and an amount of spectral surplus, based on a measured value by the monitor, and a target value set in advance; and a control unit configured to control an amount of attenuation of the variable attenuator, based on the amount of spectral narrowing and the amount of spectral surplus.

Systems, methods, and devices for adding an alien or native wavelength optical signal to a fiber optic line. A portion of a spectrum of the fiber optic line corresponding to the optical signal is blocked with a wavelength selective switch (WSS). The portion of the spectrum is gradually unblocked until a power of the optical signal measured after the WSS is equal to a predetermined level. If the power and characteristics of the optical signal after the WSS satisfy one or more criteria, the portion of the spectrum is further unblocked until the power of the optical signal measured at the output is equal to an operational level.