A transmission apparatus includes a demultiplexer configured to demultiplex a multiplexed signal including wavelength multiplexed signals having individual wavelength bands into a wavelength multiplexed signal for each of the wavelength bands, a detector configured to detect a power value of each of the wavelength multiplexed signals for each of the wavelength bands, first compensators configured to compensate for a tilt in the wavelength multiplexed signal based on the power value for each of the wavelength bands, second compensators configured to compensate for a power of the wavelength multiplexed signal for each of the wavelength bands so as to reduce a power difference among wavelength multiplexed signals after the tilt compensation based on the power value for each of the wavelength bands, and a multiplexer configured to multiplex each of the wavelength multiplexed signals after the power compensation and output a multiplexed signal.

Systems and methods for auto-squelching problematic channels of an optical spectrum and replacing them with Amplified Spontaneous Emission (ASE) channel holders are provided. A method is provided according to one implementation. In response to analyzing optical signals propagating in an optical line system, the method includes the step of determining whether one or more channels of a spectrum of the optical signals are problematic. The one or more problematic channels are determined to be problematic based on the severity of a negative impact that the one or more problematic channels have on spectrum health. The method also includes the step of auto-squelching the one or more problematic channels and replacing the one or more problematic channels with one or more Amplified Spontaneous Emission (ASE) channel holders.

A proactive and non-obtrusive channel probing scheme is provided to accurately predict channel power, gain, and optical signal to noise ratio (OSNR) without disrupting the existing connections. In one example, using a probe signal with 5 s pulse duration in a single-hop network, rapid wavelength switching is achieved with power excursions less than or equal to 0.2 dB for different loading configurations.

A proactive and non-obtrusive channel probing scheme is provided to accurately predict channel power, gain, and optical signal to noise ratio (OSNR) without disrupting the existing connections. In one example, using a probe signal with 5 s pulse duration in a single-hop network, rapid wavelength switching is achieved with power excursions less than or equal to 0.2 dB for different loading configurations.

A method is described in which a loss of spectrum in an optical signal having an optical signal spectrum is detected. The optical signal is transmitted from a first node to a second node. In response to detecting the loss of spectrum in the optical signal, at least one idler carrier without data imposed is supplied into the optical signal spectrum transmitted from the first node to the second node, the optical signal spectrum encompassing a frequency band including a plurality of optical channels, the idler carrier being amplified stimulated emission light having a frequency corresponding to a first optical channel of the plurality of optical channels.

A method is described in which a loss of spectrum in an optical signal having an optical signal spectrum is detected. The optical signal is transmitted from a first node to a second node. In response to detecting the loss of spectrum in the optical signal, at least one idler carrier without data imposed is supplied into the optical signal spectrum transmitted from the first node to the second node, the optical signal spectrum encompassing a frequency band including a plurality of optical channels, the idler carrier being amplified stimulated emission light having a frequency corresponding to a first optical channel of the plurality of optical channels.

A transmitter (TX) for a WDM optical link includes a light source (CS) generating a plurality of discrete lines (EL) with different frequencies (f), a plurality of modulators (FSM, RRM, MZM), each modulator (FSM, RRM, MZM) being configured to modulate one of the discrete lines (EL) according to a data stream (c.sub.1-c.sub.4), at least one optical amplifier (SOA) configured to simultaneously amplify multiple lines (EL), wherein only a subset of the generated lines (EL) is routed to the optical amplifier (SOA) resp. to each one of the optical amplifiers (SOA). A receiver (RX) for an optical link adapted to work together with the transmitter (TX) is also described. An optical link including the transmitter (TX) and/or the receiver (RX), and a method to operate said link are also described.

A transmitter (TX) for a WDM optical link includes a light source (CS) generating a plurality of discrete lines (EL) with different frequencies (f), a plurality of modulators (FSM, RRM, MZM), each modulator (FSM, RRM, MZM) being configured to modulate one of the discrete lines (EL) according to a data stream (c.sub.1-c.sub.4), at least one optical amplifier (SOA) configured to simultaneously amplify multiple lines (EL), wherein only a subset of the generated lines (EL) is routed to the optical amplifier (SOA) resp. to each one of the optical amplifiers (SOA). A receiver (RX) for an optical link adapted to work together with the transmitter (TX) is also described. An optical link including the transmitter (TX) and/or the receiver (RX), and a method to operate said link are also described.

In order to provide a feature with which it is possible to suppress the occurrence of an optical surge independently of the type of optical switch, there is provided an optical control device for processing inputted first light and outputting second light, wherein the optical control device is provided with: a switching unit for switching and outputting first light that has undergone a selected process; and a variable output unit connected in series to the switching unit, the variable output unit operating so as to reduce the optical power of the second light before switching by the switching unit is executed and to gradually increase the optical power of the second light after the switching is executed.

In order to provide a feature with which it is possible to suppress the occurrence of an optical surge independently of the type of optical switch, there is provided an optical control device for processing inputted first light and outputting second light, wherein the optical control device is provided with: a switching unit for switching and outputting first light that has undergone a selected process; and a variable output unit connected in series to the switching unit, the variable output unit operating so as to reduce the optical power of the second light before switching by the switching unit is executed and to gradually increase the optical power of the second light after the switching is executed.