Abstract: The embodiments of the invention relate to a line switching component separable from a line card of a network node. The line switching component contains at least one input port for receiving an optical input signal from an optical transport network and at least one output port for transmitting an optical output signal to the optical transport network. The line switching component further contains at least one further output port configured to be connected to an input port of at least one optical interface of the line card and at least one further input port configured to be connected to an output port of the at least one further optical interface of the line card. The line switching component further contains a switchable optical path system configured to operate the line switching component in a first operation mode and to operate the line switching component in a second operation mode.

Abstract: Embodiments relate to an apparatus for a regenerative network node between a first and a second link portion. The apparatus comprises an input configured to receive, from the first link portion, a signal impaired by the first link portion, the signal including a data packet with a Forward Error Correction (FEC) encoded payload portion and a header portion. The apparatus comprises a signal regeneration unit configured to mitigate signal impairments of the first link portion to provide a regenerated FEC encoded payload portion. The apparatus comprises a processing unit configured to extract destination information in the data packet's header portion. If extracted destination information indicates that the data packet's destination is the regenerative network node, the data packet's regenerated FEC encoded payload portion is forwarded to a decoding unit of the regenerative network node. Else, the data packet's regenerated FEC encoded payload portion is forwarded to the second link portion.

Abstract: The embodiments of the invention relate to a line switching component separable from a line card of a network node. The line switching component contains at least one input port for receiving an optical input signal from an optical transport network and at least one output port for transmitting an optical output signal to the optical transport network. The line switching component further contains at least one further output port configured to be connected to an input port of at least one optical interface of the line card and at least one further input port configured to be connected to an output port of the at least one further optical interface of the line card. The line switching component further contains a switchable optical path system configured to operate the line switching component in a first operation mode and to operate the line switching component in a second operation mode.

Abstract: Embodiments relate to an apparatus for a regenerative network node between a first and a second link portion. The apparatus comprises an input configured to receive, from the first link portion, a signal impaired by the first link portion, the signal including a data packet with a Forward Error Correction (FEC) encoded payload portion and a header portion. The apparatus comprises a signal regeneration unit configured to mitigate signal impairments of the first link portion to provide a regenerated FEC encoded payload portion. The apparatus comprises a processing unit configured to extract destination information in the data packet's header portion. If extracted destination information indicates that the data packet's destination is the regenerative network node, the data packet's regenerated FEC encoded payload portion is forwarded to a decoding unit of the regenerative network node. Else, the data packet's regenerated FEC encoded payload portion is forwarded to the second link portion.

Abstract: It is disclosed an optical coherent receiver for an optical communication network. The optical coherent receiver is configured to receive a modulated optical signal and to process it for generating an in-phase component and a quadrature component. The optical coherent receiver comprises a power adjuster in turn comprising a multiplying unit and a retroactively connected digital circuit. The multiplying unit is configured to multiply the in-phase and quadrature components by in-phase and quadrature gains, respectively, thereby providing power-adjusted in-phase and quadrature components. The digital circuit is configured to compute: a common gain indicative of a sum of the powers of the power-adjusted in-phase and quadrature components; a differential gain indicative of a difference between the powers of the power-adjusted in-phase and quadrature components; and the in-phase and quadrature gains as a product and a ratio, respectively, between the common gain and the differential gain.

Abstract: Proposed is a method of decoding a differentially encoded PSK modulated optical data signal carrying FEC encoded data values. The optical signal is corrected by an estimated phase offset. From the corrected signal, respective likelihood values for the FEC encoded data values are derived, using an estimation algorithm which accounts for a differential encoding rule used for differentially encoding the optical signal. The derived likelihood values are limited to a predetermined range of values. From the limited likelihood values, FEC decoded data values are derived, using an algorithm which accounts for a FEC encoding rule used for FEC encoding the FEC encoded data values.

Abstract: Proposed is a method of deriving differentially decoded data values from a received differentially encoded phase modulated optical signal. The method uses an estimation algorithm in order to find derive a sequence of differentially decoded data values. The algorithm stipulates transition probabilities between hypothetical first states, representing differentially encoded data symbols assuming that no phase slip has occurred, and transition probabilities towards hypothetical second states, which represent differentially encoded data symbols assuming that a phase slip has occurred. The transition probabilities between the first and second states are weighted on the basis of a predetermined phase slip probability value.

Abstract: In order to provide very fast tuning of an coherent optical receiver, an apparatus for use in optical telecommunications includes a coherent optical receiver with a converter stage adapted to convert a received optical signal to an electrical signal by down-converting the received optical signal in frequency using a local oscillator signal, an analog/digital converter stage adapted to sample the converted signal, a digital processor adapted to process the sampled signal to restore a transmitted data signal, and a wavelength selector adapted to select from a distribution network an unmodulated light signal at a configurable wavelength for use as the local oscillator signal. The distribution network is an optical bus system in the form of a fiber ring.

Abstract: In one embodiment, an optical receiver has a bulk dispersion compensator and a butterfly equalizer serially connected to one another to perform dispersion-compensation processing and electronic polarization de-multiplexing. The bulk dispersion compensator has a relatively large dispersion-compensation capacity, but is relatively slow and operates in a quasi-static configuration. The butterfly equalizer has a relatively small dispersion-compensation capacity, but can be dynamically reconfigured on a relatively fast time scale to track the changing conditions in the optical-transport link. The optical receiver has a feedback path that enables the configuration of the bulk dispersion compensator to be changed based on the configuration of the butterfly equalizer in a manner that advantageously enables the receiver to tolerate larger amounts of chromatic dispersion and/or polarization-mode dispersion than without the use of the feedback path.

Abstract: Proposed is a method of decoding a differentially encoded PSK modulated optical data signal carrying FEC encoded data values. The optical signal is corrected by an estimated phase offset. From the corrected signal, respective likelihood values for the FEC encoded data values are derived, using an estimation algorithm which accounts for a differential encoding rule used for differentially encoding the optical signal. The derived likelihood values are limited to a predetermined range of values. From the limited likelihood values, FEC decoded data values are derived, using an algorithm which accounts for a FEC encoding rule used for FEC encoding the FEC encoded data values.

Abstract: In one embodiment, an optical receiver has a bulk dispersion compensator and a butterfly equalizer serially connected to one another to perform dispersion-compensation processing and electronic polarization de-multiplexing. The bulk dispersion compensator has a relatively large dispersion-compensation capacity, but is relatively slow and operates in a quasi-static configuration. The butterfly equalizer has a relatively small dispersion-compensation capacity, but can be dynamically reconfigured on a relatively fast time scale to track the changing conditions in the optical-transport link. The optical receiver has a feedback path that enables the configuration of the bulk dispersion compensator to be changed based on the configuration of the butterfly equalizer in a manner that advantageously enables the receiver to tolerate larger amounts of chromatic dispersion and/or polarization-mode dispersion than without the use of the feedback path.

Abstract: Proposed is a method of deriving differentially decoded data values from a received differentially encoded phase modulated optical signal. The method uses an estimation algorithm in order to find derive a sequence of differentially decoded data values. The algorithm stipulates transition probabilities between hypothetical first states, representing differentially encoded data symbols assuming that no phase slip has occurred, and transition probabilities towards hypothetical second states, which represent differentially encoded data symbols assuming that a phase slip has occurred. The transition probabilities between the first and second states are weighted on the basis of a predetermined phase slip probability value.

Abstract: It is disclosed an optical coherent receiver for an optical communication network. The optical coherent receiver is configured to receive a modulated optical signal and to process it for generating an in-phase component and a quadrature component. The optical coherent receiver comprises a power adjuster in turn comprising a multiplying unit and a retroactively connected digital circuit. The multiplying unit is configured to multiply the in-phase and quadrature components by in-phase and quadrature gains, respectively, thereby providing power-adjusted in-phase and quadrature components. The digital circuit is configured to compute: a common gain indicative of a sum of the powers of the power-adjusted in-phase and quadrature components; a differential gain indicative of a difference between the powers of the power-adjusted in-phase and quadrature components; and the in-phase and quadrature gains as a product and a ratio, respectively, between the common gain and the differential gain.

Abstract: An optoelectronic receiver and associated method of operation.

Abstract: A signal receiver, such as an RF-matched filter receiver, includes an optical source (e.g. a mode-locked laser) providing an optical signal, and a first optical modulator to modulate the optical signal with a received RF signal and provide a modulated optical signal. A second optical modulator modulates the modulated optical signal with a reference signal and provides a twice modulated optical signal. The modulators may be Mach-Zehnder Modulators (MZM) and/or Indium Phosphide (InP) modulators. An optical detector receives the twice modulated optical signal and provides a detected signal, and a processing unit receives the detected signal and extracts or measures cross-correlation between the received RF signal and the reference signal.

Abstract: The present invention provides an optical beamforming RF transmitter. In one embodiment, the optical beamforming RF transmitter includes an optical WDM splitter having an input and a plurality of outputs. The optical beamforming RF transmitter also includes an array of antennas, where each antenna has an optical input configured to drive the corresponding antenna, and an array of optical modulators, such that each modulator has an output connected to a corresponding one of the antennas and an input connected to one of the outputs of the optical WDM splitter. The optical beamforming RF transmitter further includes a mode-locked laser having an output optically coupled to the input of the optical WDM splitter.

Abstract: An apparatus includes an optical splitter, an optical combiner, first and second optical paths, and a digital signal generator. The optical splitter has an input port and first and second output ports. The optical combiner has first and second input ports and an output port. The first optical path couples the first output port of the splitter to the first input port of the combiner. The second optical path couples the second output port of the splitter to the second input port of the combiner. Each optical path includes an electro-optical phase shifter, and one of the optical paths includes an electro-optical attenuator. The digital signal generator is configured to apply binary-valued voltage signals to control inputs of the phase shifters and the attenuator.

Abstract: An optoelectronic receiver and associated method of operation.

Abstract: A method is provided for identifying a contaminant in a gaseous space. The method includes: generating a broadband optical waveform; shaping the optical waveform to match an expected waveform for a known contaminant; and transmitting the shaped optical waveform towards an unknown contaminant. Upon receiving a reflected optical waveform from the unknown contaminant, determining whether the unknown contaminant correlates to the known contaminant based on the reflected waveform.

Abstract: An optical heterodyne receiver and a method of extracting data from a phase-modulated input optical signal. In one embodiment, the optical heterodyne receiver includes: (1) a photonic quadrature demodulator having first and second optical inputs and first and second electrical outputs and configured to generate at the first and second electrical outputs an in-phase signal and a quadrature-phase signal, respectively, in response to receiving a modulated optical signal at the first optical input and a reference optical oscillator signal at the second optical input, (2) a passive radio frequency single sideband demodulator coupled to the photonic quadrature demodulator and configured to extract at least one sideband of the in-phase signal or the quadrature-phase signal and (3) at least one analog-to-digital converter coupled to the passive radio frequency single sideband demodulator and configured to receive and sample the at least one sideband.