Abstract: An arrangement is described for compensating intra-channel nonlinearities in an optical communications system which combines optical dispersion compensation with electronic pre-distortion (EPD). EPD with moderate lookup table size can effectively suppress intra-channel nonlinearities over optical transmission links incorporating optical dispersion compensation. The arrangement can be implemented for a variety of optical communications systems, including 10 Gb/s, 40 Gb/s and higher bit rate systems as well as single-channel and wavelength-division multiplexing (WDM) systems.

Abstract: An exemplary apparatus includes a processor configured to compress an A11 message into a compressed message. The processor assigns a first value to a first portion of a first octet of the compressed message based on a message type field of the A11 message. The first portion may be three bits in length. The processor may also assign a second value to a second portion of the first octet of the compressed message based on a code field, a flags field and a status field of the A11 message. The second value may correspond to a set of values for the code, flags and status fields and may be five bits long. Third and fourth values are assigned to portions of a second octet of the compressed message based on an information element identifier and other field/s respectively of the A11 message so as to uniquely identify an information element.

Abstract: System, apparatus and method of optical communication are provided for performing digital compensation of the self-phase modulation (SPM) effect experienced by a polarization-division multiplexed (PDM) orthogonal frequency-division multiplexed (OFDM) signal in fiber transmission by compensating a complex digital waveform representing one orthogonal polarization component of the optical PDM-OFDM signal based on both digital waveforms representing two orthogonal polarization components of the PDM-OFDM signal. The compensation of the digital waveform may be further based on an anticipated mean total nonlinear phase shift experienced by the signal during fiber transmission due to SPM. The compensation may be divided into pre-compensation at the PDM-OFDM transmitter and post-compensation at the PDM-OFDM receiver.

Abstract: Method, corresponding apparatus and system are provided for transparently testing replacement functionality and optionally migrating subscribers on analog phone lines, served, for example, by PSTN Class 5 elements, to Next Generation Network (NGN) elements when copper co-termination is leveraged. According to an exemplary method, a telephone line for a telephone number is accessed through a metallic test access circuit of an analog network element and it is determined if the telephone line is available to test. If the telephone line is available to test, a port of a Next Generation Network element corresponding to the telephone number is activated, and it is determined whether a copper connection to the port of the Next Generation Network element is operating properly based on a voltage level received through the analog network element.

Abstract: Embodiments for optical communication are provided in which subbands of a multi-carrier optical signal are digital coherent detected and then processed to recover data carried by the modulated carriers corresponding to at least one of the subbands. An exemplary optical communication system includes a multi-carrier coherent optical receiver for receiving a multi-carrier optical signal having M modulated carriers that are frequency locked, wherein M is greater than 2. The multi-carrier coherent optical receiver includes a subband digital coherent detector configured to provide output signals in a digital form for N different subbands of the multi-carrier optical signal, where N is an integer greater than 1 and less than M; and a digital signal processor configured to process the digital form of the detected output signals in order to recover the data carried by the modulated carriers corresponding to at least one of the subbands of the multicarrier optical signal.

Abstract: An exemplary apparatus for digital coherent detection of a multi-wavelength signal includes a polarization-diversity optical hybrid, at least four Wavelength De-Multiplexing (W-DMUX) filters, 4M detectors, and 4M analog-to-digital converters (ADCs), with M an integer greater than one. The hybrid has a first input for receiving a multi-wavelength signal including M sub-channels at different wavelengths, and a second input for receiving a reference light source including M continuous-wave references at different wavelengths that approximates center wavelengths of the M sub-channels. The hybrid has at least four outputs. A W-DMUX input for each W-DMUX filter is provided a corresponding one of the hybrid outputs, and each W-DMUX filter provides M filtered optical channel outputs. Each detector converts at least one of the filtered channel outputs into a corresponding electrical signal. Each ADC converts one of the electrical signals into a corresponding digital signal.