A reconfigurable optical add/drop multiplexer (ROADM) includes a plurality of interconnected ROADM blocks. Each ROADM block includes an ingress switchable-gain amplifier, an output power detector coupled to an output of the ingress switchable gain amplifier, and a wavelength-selective switch coupled to the output of the ingress switchable gain amplifier. Each ROADM block includes a plurality of add/drop blocks coupled to the wavelength-selective switches of the plurality of ROADM blocks. The ROADM includes a controller configured to receive an indication of an output signal power from the output power detector and adjust gain and equalization parameters of the ingress switchable-gain amplifier based on the received indication of the output signal power.

A phase noise compensation apparatus is used for a demodulation apparatus for demodulating a transmission signal modulated by a modulation scheme that uses phase information for data identification. A phase detector detects a phase error of a reception pilot symbol sequence included in a reception symbol sequence. A first filter refers to the phase error detected in a time series manner and sequentially estimates first phase noise components. A second filter refers to the phase error detected in a reverse time series manner and sequentially estimates second phase noise components. The synthesis processing unit estimates a phase noise component of a reception symbol based on an estimated value of the first phase noise component, an estimated value of the second phase noise component, and the phase error. The phase rotator rotates a phase of the reception symbol based on the estimated phase noise component of the reception symbol.

Example embodiments of the present invention relate to a software programmable reconfigurable optical add drop multiplexer (ROADM) comprising of a plurality of wavelength switches and a plurality of waveguide switches, wherein when the plurality of waveguide switches are set to a first switch configuration, the software programmable ROADM provides n degrees of an n-degree optical node, and wherein when the waveguide switches are set to a second switch configuration, the software programmable ROADM provides k degrees of an m-degree optical node.

Systems and methods are described for transmitting information optically. For instance, a system may include an optical source configured to generate a beam of light. The system may include at least one modulator configured to encode data on the beam of light to produce an encoded beam of light/encoded plurality of pulses. The system may include a spectrally-equalizing amplifier configured to receive the encoded beam of light/encoded plurality of pulses from the at least one modulator and both amplify and filter the encoded beam of light/encoded plurality of pulses to produce a filtered beam of light/filtered plurality of pulses, thereby spectrally equalizing a gain applied to the encoded beam of light. In some cases, the system may slice the beam of slight, to ensure a detector has impulsive detection. In some cases, the system may include a temperature controller to shift a distribution curve of wavelengths of the optical source.

A filter includes a first filter component coupled to a second filter component. The first filter component is configured to receive an optical signal, and filter the optical signal based on a first power difference of signals transmitted on a plurality of frequency bands in the optical signal, where the first power difference includes a difference caused by a first doped optical fiber. The second filter component is loaded with a first driving electrical signal used to control a frequency response of the second filter component. The second filter component is configured to filter, using the frequency response based on a second power difference of the signals transmitted on the plurality of frequency bands, an optical signal obtained after the filtering by the first filter component.

An optical amplifier may include an erbium-doped fiber and an optical coupler coupled to the erbium-doped fiber. In some embodiments, a length of the erbium-doped fiber may be selected for an amplification gain applied by the optical amplifier. The optical coupler may be configured to multiplex one or more optical data signals and an optical pump signal from an optical pump onto the erbium-doped fiber such that the erbium-doped fiber may amplify a first continuous range of wavelengths of the optical data signals. The optical amplifier may further include a filter coupled to the erbium-doped fiber and configured to attenuate a second continuous range of wavelengths. In some embodiments, the second continuous range may be less than the first continuous range and positioned within the first continuous range.

A reconfigurable optical add/drop multiplexer (ROADM) includes a plurality of interconnected ROADM blocks. Each ROADM block includes an ingress switchable-gain amplifier, an output power detector coupled to an output of the ingress switchable gain amplifier, and a wavelength-selective switch coupled to the output of the ingress switchable gain amplifier. Each ROADM block includes a plurality of add/drop blocks coupled to the wavelength-selective switches of the plurality of ROADM blocks. The ROADM includes a controller configured to receive an indication of an output signal power from the output power detector and adjust gain and equalization parameters of the ingress switchable-gain amplifier based on the received indication of the output signal power.

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.

[Problem] To accommodate single-band signal processing devices in a high-density manner.

[Solution] Provided is a system including: a first signal cable; a second signal cable; a third signal cable; a fourth signal cable; a first multi-band signal processing device that processes a first signal input from the first signal cable and outputs a resultant second signal to the second signal cable; a second multi-band signal processing device that processes a third signal input from the third signal cable and outputs a resultant fourth signal to the fourth signal cable; a first joint box that accommodates the first signal cable, the first multi-band signal processing device, the second signal cable, and the fourth signal cable; and a second joint box that accommodates the second signal cable, the third signal cable, the second multi-band signal processing device, and the fourth signal cable.

A receiver (e.g., for a 10G fiber communications link) includes an interleaved ADC coupled to a multi-channel equalizer that can provide different equalization for different ADC channels within the interleaved ADC. That is, the multi-channel equalizer can compensate for channel-dependent impairments. In one approach, the multi-channel equalizer is a feedforward equalizer (FFE) coupled to a Viterbi decorder, for example, a sliding block Viterbi decoder (SBVD); and the FFE and/or the channel estimator for the Viterbi decoder are adapted using the LMS algorithm.