Abstract: Systems, devices and techniques for processing received QPSK modulated optical signals include sampling the received signal at twice the baud rate, thereby producing samples that are then processed as 9-QAM symbols using a decision directed least squares optimization method. A third stage of channel equalization is filtering performs channel equalization to mitigate linear filtering effects along the transmission link. Data bits are then recovered from the resulting symbol estimates. The received optical signal may also include dual polarized signals for increased bandwidth capacity.

Abstract: A blind equalization technique of high-order QAM signals is provided. A method implemented at a receiver-side in an optical communication network receives an optical signal and performs a two-step polarization tracking process on the received optical signal. Using another method, a polarization multiplexed optical transmission is received by a receiver and a polarization tracking process is performed by applying two different algorithms in parallel. One algorithm may be a decision directed least means square (DD-LMS) algorithm. Another algorithm may be a constant modulus algorithm (CMA).

Abstract: Techniques for receiving a modulated optical signal which has undergone a digital Fourier transform spreading (DFTS), include generating digital samples of the modulated optical signal, performing resampling and synchronization of the digital samples to generate time-corrected digital samples from an input wireless signal, compensating the time-corrected digital samples for nonlinearity (NL) to produce NL-compensated digital samples, de-spreading the NL-compensated digital samples using an inverse digital Fourier transform to recover quadrature amplitude modulation (QAM) modulated signals, applying post-equalization to the QAM signals to generate equalized QAM signals, performing a decision directed least mean square (DD-LMS) equalization to generate blind-optimized QAM signals and demodulating the blind-optimized QAM signals to recover data bits.

Abstract: Throughput between a transmitter and a receiver is increased by performing a three-stage joint channel optimization in which training sequences are used for calculating a pre-equalization estimate in the first stage, a look up table for pre-distortion in the second stage and a further updating the pre-equalization estimate and the look up table based on a third stage in which the training sequence used for the updating is pre-equalized and pre-distorted using previously calculated values prior to transmitting from the transmitter to the receiver.

Abstract: A latch for a closure panel of a vehicle including a latch housing; a ratchet mounted to the latch housing and movable between a closed position and an open position, the ratchet having a channel for receiving a striker with a first portion relative to the channel and a second portion relative to the channel, the channel having an over slam region positioned adjacent to a bottom of the channel; a pawl mounted to the latch housing and movable between a ratchet holding position and a ratchet release position; and a pair of levers mounted to the latch housing and configured for corotation about a pivot, the pair of levers biased towards a rest position by a biasing member coupled to at least one of the pair of levers.

Abstract: A method of optical communication, implemented at a receiver in an optical communication network, includes receiving an optical signal carrying modulated information bits, processing the optical signal through a receiver subsystem to generate a stream of digitized modulation symbols from the optical signal, and producing, using the digitized modulation symbols as input symbols to an iterative process, estimates of information bits. Each iteration includes: generating estimated output symbols from input symbols by filtering by an estimate of inverse of the optical channel, updating, using the estimated output symbols, the estimate of the inverse of the optical channel to minimize a measure of error, and compensating the estimated output symbols by using pre-distortion values from a look-up table (LUT) to generate compensated output symbols that are used as input to a next iteration.

Abstract: An exemplary technique of optical signal transmission in which modulated optical signals are generated using photonic heterodyne beating and operating a digital to analog converter at baseband includes receiving information bits, modulating the information bits to generate a precoded vector signal at baseband, generating, using photonic heterodyne beating, from the precoded vector signal at baseband, a precoded vector signal at an upconverted frequency, and transmitting the precoded vector signal at the upconverted frequency on the optical communication network.

Abstract: Embodiments of the present invention pertain to optical wireless architecture and, in particular, to novel optical architecture to provide fiber-optic and wireless communication systems, links, and access networks. Certain embodiments of the invention pertain to a novel method and apparatus to provide 109.6 Gb/s capacity over spans of 80-km SMF and 2×2 MIMO. Conversion of PM-QAM modulated wireless mm-wave signal to an optical signal as well as 80-km fiber transmission of the converted optical signal is also realized.

Abstract: A dual-polarization, 2-subcarriers code orthogonal, orthogonal frequency division multiplexed signal carrying information bits is transmitted in an optical communication network without transmitting a corresponding pilot tone or training sequence. A receiver receives the transmitted signal and recovers information bits using a blind equalization technique and by equalizing the 2-subcarriers OFDM signal as a 9-QAM signal in time domain with a CMMA (constant multi modulus algorithm) equalization method.

Abstract: A transmitter of optical signals uses a single light transmitter to modulate a multi-carrier signal. The multi-carrier signal is generated by performing digital signal processing in the digital domain to generate a plurality of components by performing Hilbert transform filtering. The components are modulated on to an optical transmitter as in-phase and quadrature components, thereby generating a multi-carrier waveform using a single optical transmitter.

Abstract: Methods and apparatus to realize high spectral efficiency in optical signals transmitted over long distances.

Abstract: A dual-polarization, 2-subcarriers code orthogonal, orthogonal frequency division multiplexed signal carrying information bits is transmitted in an optical communication network without transmitting a corresponding pilot tone or training sequence. A receiver receives the transmitted signal and recovers information bits using a blind equalization technique and by equalizing the 2-subcarriers OFDM signal as a 49-QAM signal in time domain with a CMMA (constant multi modulus algorithm) equalization method.

Abstract: A novel and simple photonic vector signal generation scheme at radio frequency (RF) bands enabled by a single-drive Mach-Zehnder modulator (MZM)-based optical carrier suppression (OCS) without precoding techniques and optical filter, which can reduce the complexity of transmitter digital signal processing (DSP), is described. The generation and reception of 16/20/22-Gbaud quadrature-phase-shift-keying (QPSK) vector signals at 16/20/22 GHz are experimentally demonstrated, respectively. The measured bit-error ratio for 16 G-baud QPSK vector signals after transmitting over 10-km standard single mode fiber (SSMF) can be under 7% hard-decision forward-error-correction (HD-FEC) threshold of 3.8×10?3. Moreover, compared to the conventional precoding scheme, the receiver sensitivity can be enhanced by 4 dB at both back-to-back (BTB) and after 10-km SSMF transmission cases, which demonstrates the feasibility of this technique, and show its potential promising application in radio over fiber (RoF) system.

Abstract: An optical transmitter transmits a dual polarization optical Nyquist frequency domain multiplexed signal. The signal includes a first polarization component and a second polarization component. Each component comprises multiple subchannels, possibly having different subchannel bandwidths and different modulation schemes. An optical receiver receives the signal and recovers transmitted data.

Abstract: An optical signal transmitter produces optical signals comprising QAM modulated vector signals generated using a single external electro-optical modulator operated in conjunction with a wavelength selective switch. The transmission processing achieves adaptive photonic frequency multiplication and comprises QAM modulated signals with high order constellations such as 8-QAM, 16-QAM, 32-QAM and 64-QAM.

Abstract: An optical communication system includes a transmission apparatus that transmits a test signal over an optical communication medium using a first optical modulation format, receives a reception report for the test signal, determines, based on the received reception report, a pre-equalization scheme, applies the pre-equalization to data transmitted from the transmitter side to generate pre-equalized data and transmits the pre-equalized data using a second optical modulation format based on the reception report. An optical reception apparatus receives the test signal, computes a channel transfer function based on the received test signal, and transmits the reception report.

Abstract: An optical transmitter determines the transfer function in the reference-based pre-equalization for applying to an optically modulated signal at the transmitter. The determined pre-equalization transfer function is made robust to linewidth inaccuracy of the optical source by performing phase correction during the calculation of the pre-equalization transfer function. The phase correction includes averaging a number of consecutive received phase samples. The determined pre-equalization transfer function is applied to modulated signals prior to the transmission over an optical medium.

Abstract: The filter estimate produced by post-equalization processing of an optical signal at a receiver is used to generate pre-equalizer filter coefficients that are communicated back to the source of the optical signal for performing pre-equalization. In one advantageous aspect, the already existing post-equalization modules of an optical receive equipment can thus be used to produce, in addition, a pre-equalizer filter for use by the source side.

Abstract: An optical signal transmitter produces optical signals comprising QAM modulated vector signals generated using a single external electro-optical modulator operated in conjunction with a wavelength selective switch. The transmission processing achieves adaptive photonic frequency multiplication and comprises QAM modulated signals with high order constellations such as 8-QAM, 16-QAM, and 64-QAM.

Abstract: Duo-binary encoding is used for encoding I and Q data prior to performing orthogonal frequency division multiplexing based transmission using discrete Fourier transform spreading (DFT-S). Advantageously, duo-binary encoding improves robustness of the encoded signal to inter symbol interference, making the degradation caused by the subsequent DFT-S stage less susceptible to reduction in bit error rate performance.