Abstract: A technique is provided for a receiver of an optical signal. The technique includes an apparatus that is configured to input digitized samples of the optical signal at a first sampling rate. The apparatus is further configured to filter the digitized samples based on a plurality of filter coefficients to obtain filtered samples of the optical signal at a second sampling rate. The second sampling rate is different from the first sampling rate. The apparatus is further configured to output the filtered samples of the optical signal at the second sampling rate.

Abstract: In some embodiments, an apparatus includes a processor configured to receive a set of digital samples associated with a set of optical signals received at a coherent optical receiver. The set of digital samples is associated with a set of optical channels. Each optical channel from the set of optical channels is spaced from at least one adjacent optical channel from the plurality of optical channels. The processor is configured to calculate, for each optical channel from the set of optical channels, a spacing between that optical channel and at least one adjacent optical channel from the set of optical channels based on digital signal processing of the set of digital samples. The processor is configured to send a signal indicating, for each optical channel from the set of optical channels, the spacing between that optical channel and the at least one adjacent optical channel.

Abstract: A method may include causing a signal to be transmitted that includes a plurality of wavelengths. The signal may be transmitted via an optical fiber that is associated with a particular wavelength. The particular wavelength may be included in the plurality of wavelengths. The method may include filtering the signal, based on the particular wavelength, to generate a filtered signal. The filtered signal may include the particular wavelength. The method may include detecting the filtered signal in association with the optical fiber. The method may include determining the particular wavelength based on the filtered signal. The method may include storing or providing information identifying at least one of the particular wavelength, the optical fiber, or a transmitter that transmitted the signal.

Abstract: In some embodiments, an apparatus includes a processor configured to receive a set of digital samples associated with a set of optical signals received at a coherent optical receiver. The set of digital samples is associated with a set of optical channels. Each optical channel from the set of optical channels is spaced from at least one adjacent optical channel from the plurality of optical channels. The processor is configured to calculate, for each optical channel from the set of optical channels, a spacing between that optical channel and at least one adjacent optical channel from the set of optical channels based on digital signal processing of the set of digital samples. The processor is configured to send a signal indicating, for each optical channel from the set of optical channels, the spacing between that optical channel and the at least one adjacent optical channel.

Abstract: A wavelength division multiplexing (WDM) transceiver module comprising an optical port and an optical modulator is disclosed herein. The optical port includes a data transmit and receive optical fiber connector and a laser source-in optical fiber connector. The laser source-in optical fiber connector is configured to couple to a laser source external to the WDM transceiver module, and provide polarization alignment for a polarization-maintaining fiber. The optical modulator is configured to receive a laser output from the external laser source via the polarization-maintaining fiber and modulate the laser output based on analog electrical signals generated by a digital signal processor. The WDM transceiver module may not including an onboard laser source.

Abstract: A method may include causing a signal to be transmitted that includes a plurality of wavelengths. The signal may be transmitted via an optical fiber that is associated with a particular wavelength. The particular wavelength may be included in the plurality of wavelengths. The method may include filtering the signal, based on the particular wavelength, to generate a filtered signal. The filtered signal may include the particular wavelength. The method may include detecting the filtered signal in association with the optical fiber. The method may include determining the particular wavelength based on the filtered signal. The method may include storing or providing information identifying at least one of the particular wavelength, the optical fiber, or a transmitter that transmitted the signal.

Abstract: A wavelength division multiplexing (WDM) transceiver module comprising an optical port and an optical modulator is disclosed herein. The optical port includes a data transmit and receive optical fiber connector and a laser source-in optical fiber connector. The laser source-in optical fiber connector is configured to couple to a laser source external to the WDM transceiver module, and provide polarization alignment for a polarization-maintaining fiber. The optical modulator is configured to receive a laser output from the external laser source via the polarization-maintaining fiber and modulate the laser output based on analog electrical signals generated by a digital signal processor. The WDM transceiver module may not including an onboard laser source.

Abstract: A wavelength division multiplexing (WDM) transceiver module comprising an optical port and an optical modulator is disclosed herein. The optical port includes a data transmit and receive optical fiber connector and a laser source-in optical fiber connector. The laser source-in optical fiber connector is configured to couple to a laser source external to the WDM transceiver module, and provide polarization alignment for a polarization-maintaining fiber. The optical modulator is configured to receive a laser output from the external laser source via the polarization-maintaining fiber and modulate the laser output based on analog electrical signals generated by a digital signal processor. The WDM transceiver module may not including an onboard laser source.

Abstract: In some embodiments, an apparatus includes an optical transceiver which includes a rate-adaptive forward error correction (FEC) encoder and a rate-adaptive FEC decoder. The rate-adaptive FEC encoder is configured to adjust a number of a set of known symbols associated with a codeword to achieve rate adaption. A length of the codeword is fixed. The rate-adaptive FEC encoder is configured to generate the codeword based on (1) a set of information symbols including the set of known symbols and a set of data symbols, and (2) a fixed number of a set of parity symbols generated using information symbols. The rate-adaptive FEC decoder is configured to receive a set of reliability values associated with a channel word, and expand the set of reliability values to produce an expanded set of reliability values. The rate-adaptive FEC decoder is further configured to decode the expanded set of reliability values.

Abstract: Techniques are described for determining pre-compensation parameters to compensate for signal integrity degradation along a signal path. A processor generates a first digital signal and receives a second digital signal. The second digital signal is generated from an optical-to-electrical conversion of a feedback optical signal that is generated from an electrical-to-optical conversion of an electrical signal by an optical module. The processor determines the pre-compensation parameters based on the first and second digital signals.

Abstract: In general, techniques are described for dynamically determining a logical network topology for more efficiently transporting network traffic over a physical topology based on end-to-end network traffic demands and optical transport network (OTN) characteristics of the network. The techniques may be applicable to meeting network traffic demands placed upon a multi-layer network having a base transport layer and a logical or overlay Internet Protocol (IP) layer routed on the transport layer.

Abstract: A technique is provided for a receiver of an optical signal. The technique includes an apparatus that is configured to input digitized samples of the optical signal at a first sampling rate. The apparatus is further configured to filter the digitized samples based on a plurality of filter coefficients to obtain filtered samples of the optical signal at a second sampling rate. The second sampling rate is different from the first sampling rate. The apparatus is further configured to output the filtered samples of the optical signal at the second sampling rate.

Abstract: An optical receiver (20) for multimode communications comprises: a mode demultiplexer (21) having an input connected to a multimode link (22) and a plurality of output lines (231-234), wherein the mode demultiplexer is adapted to couple each of the modal components of the optical signal substantially into a selected one of the output lines, a plurality of coherent optical detectors (251-254) respectively connected to the output lines to produce a set of electrical digital signals each comprising an in-phase component and a quadrature-phase component, a plurality of independently adjustable optical delay devices (241-244) arranged on the output lines to impart a selected delay to each of the corresponding modal components, and a signal processing device (26) adapted to process the digital signals to recover the independent modulations of the respective modal components by inverting a mode-mixing characteristic of the multimode link.

Abstract: In general, techniques are described for dynamically determining a logical network topology for more efficiently transporting network traffic over a physical topology based on end-to-end network traffic demands and optical transport network (OTN) characteristics of the network. The techniques may be applicable to meeting network traffic demands placed upon a multi-layer network having a base transport layer and a logical or overlay Internet Protocol (IP) layer routed on the transport layer.

Abstract: The present document relates to an optical communication system. In particular, the present document relates to the alignment of the laser frequency at a transmitter of the optical communication system and the local oscillator frequency at a coherent receiver of the optical communication system. A coherent optical receiver (222) is described. The receiver (222) comprises a reception unit adapted to convert a received optical signal at a carrier frequency into a digital signal using a local oscillator, referred to as LO, having an LO frequency; a spectral analysis unit adapted to estimate a degree of asymmetry of a spectrum of the received optical signal, based on the digital signal; and a transmission unit adapted to transmit an indication of the degree of asymmetry to a near-end transponder (210) comprising a transmitter (211) of the received optical signal.

Abstract: A method and a device for optical data transmission are proposed. Incoming optical signals having respective incoming waveguide modes are mapped into outgoing optical signals having respective outgoing waveguide modes, using optical spatial modulators, whose multiplicative patterns correspond to the respective electrical field patterns of the respective incoming or outgoing waveguide modes. An incoming optical signal, whose respective incoming waveguide mode is of an azimuthal order equal to zero, results in an outgoing optical signal, whose respective outgoing waveguide mode is of an azimuthal order equal to zero. Furthermore, two incoming optical signals, whose respective second incoming waveguide modes are of a same azimuthal order greater than zero, of a same radial order, and orthogonal to each other result in respective outgoing signals, whose respective outgoing waveguide modes are off a same azimuthal order greater than zero, of a same radial order and orthogonal to each other.

Abstract: A modulator with polarization marking comprising two input ports for receiving two optical signals at one wavelength, and exhibiting essentially perpendicular optical polarization states, capable of phase-modulating those signals with data signals and of combining them with polarization, characterized in that it comprises a source of phase overmodulation for overmodulating the phase of one of said two optical signals, said phase overmodulation exhibiting a modulation frequency substantially lower than the modulation frequency of said data signals. A method and a coherent receiver are also disclosed.

Abstract: The present invention refers to a method for operating a coherent optical packet receiver comprising at least one linear physical impairment compensation filter wherein the settings of at least one linear physical impairment compensation filter applied on a received optical packet having at least one given travelling parameter are determined in function of previous settings determination of said at least one linear physical impairment compensation filter achieved on at least one optical packet having a similar at least one travelling parameter as said received optical packet.

Abstract: A method and a device for optical data transmission are proposed. Incoming optical signals having respective incoming waveguide modes are mapped into outgoing optical signals having respective outgoing waveguide modes, using optical spatial modulators, whose multiplicative patterns correspond to the respective electrical field patterns of the respective incoming or outgoing waveguide modes. An incoming optical signal, whose respective incoming waveguide mode is of an azimuthal order equal to zero, results in an outgoing optical signal, whose respective outgoing waveguide mode is of an azimuthal order equal to zero. Furthermore, two incoming optical signals, whose respective second incoming waveguide modes are of a same azimuthal order greater than zero, of a same radial order, and orthogonal to each other result in respective outgoing signals, whose respective outgoing waveguide modes are off a same azimuthal order greater than zero, of a same radial order and orthogonal to each other.

Abstract: An exemplary technique is provided for a coherent optical receiver adapted to receive an optical signal transmitted over an optical transmission channel exhibiting Cross-Polarization Modulation (XPOLM). The received optical signal comprises a first polarization component and a second polarization component.