| Patent application number | Description | Published |
|---|
| 20080199191 | MAXIMUM LIKELIHOOD SEQUENCE ESTIMATION FOR HIGH SPECTRAL EFFICIENCY OPTICAL COMMUNICATION SYSTEMS - Severe inter-symbol interference (ISI), introduced by narrow-band optical filtering in high spectral efficiency wavelength-division multiplexed (WDM) systems to avoid coherent WDM crosstalk, can be substantially mitigated by the use of maximum-likelihood sequence estimation (MLSE) reception. Compared to conventional threshold detection, the use of an MLSE receiver allows, for example, a 22% reduction in optical receive filter bandwidth. For tight optical filtering, the MLSE receiver benefits from taking into account noise correlation. MLSE receivers with one and with two samples per bit are described and it is shown that while oversampling is beneficial for wide-band optical filters, the benefit goes away for narrow-band optical filtering, thereby facilitating MLSE design for rates beyond 10 Gb/s. | 08-21-2008 |
| 20100111542 | Intra-Channel Nonlinearity Compensation For Optical Data Communications - 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. | 05-06-2010 |
| 20100150559 | Time-interleaved polarization-division-multiplexed transmission systems and transmitters - A WDM system having at least two channels, each of which employs two polarizations, is arranged so that the start times of symbols carried by one polarization of a channel are displaced in time from the start times of symbols carried by the other polarization of that channel, e.g., the start time for each symbol on one polarization is not substantially synchronized with the closest-in-time symbol start time on the other polarization of that channel. Preferably, the data signals are modulated using a return-to-zero (RZ) format and the start times of the symbols of the data signal carried by one polarization of a channel is offset from the start time of the symbols data signal carried by the other polarization of that channel by between 20% to 80%—preferably 50%—of the symbol period of the data signals, when the data signals have the same symbol period. | 06-17-2010 |
| 20100150577 | Communication System and Method With Signal Constellation - An example method includes modulating an optical signal using a Phase Shift Keying (PSK) signal constellation, wherein signal points of the PSK signal constellation are located on at least two rings. The first ring has a first radius r | 06-17-2010 |
| 20100329670 | RECEIVER FOR OPTICAL TRANSVERSE-MODE-MULTIPLEXED SIGNALS - A representative optical receiver of the invention receives an optical transverse-mode-multiplexed (TMM) signal through a multimode fiber that supports a plurality of transverse modes. The optical receiver has a plurality of optical detectors operatively coupled to a digital signal processor configured to process the TMM signal to determine its modal composition. Based on the determined modal composition, the optical receiver demodulates each of the independently modulated components of the TMM signal to recover the data encoded onto the TMM signal at the remote transmitter. | 12-30-2010 |
| 20100329671 | TRANSVERSE-MODE MULTIPLEXING FOR OPTICAL COMMUNICATION SYSTEMS - An optical communication system having an optical transmitter and an optical receiver optically coupled via a multi-path fiber. The optical transmitter launches, into the multi-path fiber, an optical transverse-mode-multiplexed (TMM) signal having a plurality of independently modulated components by coupling each independently modulated component into a respective transverse mode of the multi-path fiber. The TMM signal undergoes inter-mode mixing in the multi-path fiber before being received by the optical receiver. The optical receiver processes the received TMM signal to reverse the effects of inter-mode mixing and recover the data carried by each of the independently modulated components. | 12-30-2010 |
| 20110211828 | Flexible Dispersion Mapping - One method configures an all-optical network such that at least eighty percent of optical fiber spans of a portion of a first all-optical path of the network have substantially a first residual dispersion per span and at least eighty percent of optical fiber spans of a remainder of the first all-optical path have residual dispersions per span substantially differing from the first residual dispersion per span. The remainder of the first all-optical path includes an overlap between the first all-optical path and a second all-optical path of the network. The second all-optical path has a plurality of optical fiber spans and a substantially singly periodic dispersion map. | 09-01-2011 |
| 20110243574 | MULTIMODE OPTICAL COMMUNICATION - An optical transmitter includes a set of optical waveguides and first, second, and third optical modulators. Output ends of the optical waveguides of the set form a two-dimensional array capable of end-coupling the optical waveguides of the set to a multimode optical fiber in response to the array being located to optically face one end of the multimode optical waveguide. The first optical modulator is optically connected to a first of the optical waveguides of the set, and each of the second and third optical modulators is optically connected to the second and third of the optical waveguides of the set. The set of optical waveguides is configured to provide a coupling matrix of rank three or more between the optical modulators and optical propagation modes in the multimode optical fiber. | 10-06-2011 |
