A method and system is described. A signal indicative of a failure of a first channel within a plurality of channels of a transmission signal traversing a signal working path in a network is received. The signal working path has a headend node, a tail-end node and an intermediate node. The first channel has a frequency band and a power level prior to failing. The signal working path is associated with a protection path. The protection path includes the intermediate node, optical cross-connects, and a transmitter supplying (ASE) light. The transmitter is activated to supply the ASE light within a frequency band and having a power level corresponding to the frequency band and power level associated with the first channel. The ASE light is supplied to a cross-connect, such that the cross-connect provides a transmission signal including the ASE light.

A method of reducing the power consumption of an optical fiber amplifier by which the optical output of a first optical fiber is filtered to prevent a detrimental portion of the optical output from reaching a second optical fiber, to transmit a signal for amplification, and to transmit a portion of the optical output that can contribute to optical pumping of the second optical fiber. By propagating an optical pumping portion output from the first optical fiber, as well as optical pumping from an independent source, the independent source's power level can be reduced. In a sequence of optical fibers, each fiber can provide some pumping output to one or more other fibers, as long as its optical output is properly filtered with appropriate optical components, such as a band-stop filter. A sequence can be terminated by a low-pass filter in order for a final output to contain the amplified signal free from any other optical output.

Systems, methods, and computer-readable media are provided for signaling the presence of a fault in a multi-band optical network or other communication system. In response to a detected fault in a multi-band communication system impacting a specific band of the multi-band communication system, a method, according to one implementation, may include a step of creating a fault signal corresponding to the detected fault. The method may also include the step of conveying the fault signal to at least one of an upstream controller and a downstream controller of the multi-band communication system to trigger an action for handling the fault on the specific band. The action may be handled independently of other actions associated with one or more other bands of the multi-band communication system.

Systems, methods, and computer-readable media are provided for signaling the presence of a fault in a multi-band optical network or other communication system. In response to a detected fault in a multi-band communication system impacting a specific band of the multi-band communication system, a method, according to one implementation, may include a step of creating a fault signal corresponding to the detected fault. The method may also include the step of conveying the fault signal to at least one of an upstream controller and a downstream controller of the multi-band communication system to trigger an action for handling the fault on the specific band. The action may be handled independently of other actions associated with one or more other bands of the multi-band communication system.

The disclosed systems and methods support addition of bands to a multi-band optical interface. The systems and methods can include a multi-band interface device for optical networks. The device can include a multi-band optical amplifier, a C-Band Add/Drop multiplexer, an L-Band Add/Drop multiplexer and an amplifier noise source. The multi-band optical amplifier can be connected to the C-Band Add/Drop multiplexer and connected to the L-Band Add/Drop multiplexer through the amplifier noise source. The amplifier noise source be configured to generate a combination of bulk noise and an input transmission received from the L-Band Add/Drop multiplexer. The gain of the amplifier noise source can depend on the power of the received input transmission. The power of the received input transmission can be increased over a period of time, transitioning the amplifier noise source from acting as a bulk noise source to acting an amplifier.

A method and system is described. A signal indicative of a failure of a first channel within a plurality of channels of a transmission signal traversing a signal working path in a network is received. The signal working path has a headend node, a tail-end node and an intermediate node. The first channel has a frequency band and a power level prior to failing. The signal working path is associated with a protection path. The protection path includes the intermediate node, optical cross-connects, and a transmitter supplying (ASE) light. The transmitter is activated to supply the ASE light within a frequency band and having a power level corresponding to the frequency band and power level associated with the first channel. The ASE light is supplied to a cross-connect, such that the cross-connect provides a transmission signal including the ASE light.

Described herein is an apparatus including a continuous wave idler and an optical coupler that provide an optical signal having a power greater than optical channels carrying data, and positioned at a cross-over point between two spectral bands, with each band encompassing multiple optical channels.

Systems, methods, and computer-readable media are provided for signaling the presence of a fault in a multi-band optical network or other communication system. In response to a detected fault in a multi-band communication system impacting a specific band of the multi-band communication system, a method, according to one implementation, may include a step of creating a fault signal corresponding to the detected fault. The method may also include the step of conveying the fault signal to at least one of an upstream controller and a downstream controller of the multi-band communication system to trigger an action for handling the fault on the specific band. The action may be handled independently of other actions associated with one or more other bands of the multi-band communication system.

A signal light interruption detection device includes an optical interleaver to demultiplex wavelength-multiplexed light into light in first frequency ranges corresponding to a first frequency grid including frequencies at regular frequency intervals in which a main signal light component can be arranged and light in second frequency ranges corresponding to a second frequency grid shifted from the first frequency grid by a half cycle of the regular frequency intervals, a first optical detector to detect first light power as total power of the light in the first frequency ranges, a second optical detector to detect second light power as total power of the light in the second frequency ranges, and a judgment unit to output a notification signal based on a difference between the first light power detected by the first optical detector and the second light power detected by the second optical detector.

A signal light interruption detection device includes an optical interleaver to demultiplex wavelength-multiplexed light into light in first frequency ranges corresponding to a first frequency grid including frequencies at regular frequency intervals in which a main signal light component can be arranged and light in second frequency ranges corresponding to a second frequency grid shifted from the first frequency grid by a half cycle of the regular frequency intervals, a first optical detector to detect first light power as total power of the light in the first frequency ranges, a second optical detector to detect second light power as total power of the light in the second frequency ranges, and a judgment unit to output a notification signal based on a difference between the first light power detected by the first optical detector and the second light power detected by the second optical detector.