Abstract: An optical transport system (OTS) having a plurality of optical transponders (OTs) connected via one or more optical links and adapted to communicate with one another using respective rate-adaptive forward-error-correction (FEC) codes. In one embodiment, the OTS has a rate control unit (RCU) adapted to configure the OTs to dynamically adjust the rates of the FEC codes based on an estimated performance margin for each link between two respective communicating OTs to optimize the overall capacity of the OTS while maintaining an adequate, but not excessive, overall system margin.

Abstract: Methods and apparatus are described for generating and receiving amplitude and differential-phase encoded signals in which the number of phase states at a given amplitude level is always less than or equal to that at a higher amplitude level and at least two amplitude levels have different numbers of phase states.

Abstract: A laser projector having a configurable spatial light modulator (SLM) adapted to display various spatial modulation patterns and redirect illumination from a laser to form an image on the viewing screen. The laser projector drives the SLM to change spatial modulation patterns at a rate that causes the corresponding sequence of projected images to fuse to mitigate appearance of speckle in the resulting fused image. The SLM can be designed to redirect the illumination using either diffraction or specular reflection of light from the displayed spatial modulation pattern. In one embodiment, the SLM is a MEMS device having an array of individually addressable mirrors supported over a substrate and adapted to move (e.g., translate and/or rotate) with respect to the substrate.

Abstract: An optical transport system (OTS) having a plurality of optical transponders (OTs) connected via one or more optical links and adapted to communicate with one another using respective rate-adaptive forward-error-correction (FEC) codes. In one embodiment, the OTS has a rate control unit (RCU) adapted to configure the OTs to dynamically adjust the rates of the FEC codes based on an estimated performance margin for each link between two respective communicating OTs to optimize the overall capacity of the OTS while maintaining an adequate, but not excessive, overall system margin.

Abstract: A laser projector having a configurable spatial light modulator (SLM) adapted to display various spatial modulation patterns and redirect illumination from a laser to form an image on the viewing screen. The laser projector drives the SLM to change spatial modulation patterns at a rate that causes the corresponding sequence of projected images to fuse to mitigate appearance of speckle in the resulting fused image. The SLM can be designed to redirect the illumination using either diffraction or specular reflection of light from the displayed spatial modulation pattern. In one embodiment, the SLM is a MEMS device having an array of individually addressable mirrors supported over a substrate and adapted to move (e.g., translate and/or rotate) with respect to the substrate.

Abstract: Method and apparatus for routing messages in a network includes first filters to provide frequency-based message signals converted from an optically-based signal and mixers adapted to mix the frequency-based message signals with sub-carriers to generate frequency-based sub-carrier modulated message signals. A frequency generator connected to the mixers provides the sub-carriers to the mixers and a combiner connected to the mixers combines the frequency-based sub-carrier modulated message signals. Second filters connected to the combiner receive and group the frequency-based sub-carrier modulated message signals. Optical transmitters connected to second filters optically convert and transmit the frequency-based sub-carrier modulated message signals. The frequency generator generates and applies a particular sub-carrier frequency to one of the mixers according to information contained in the frequency-based message signal.

Abstract: An optical WDM-TDM network includes a plurality of devices, each of the devices including at least one optical add/drop device adapted to drop optical signals of at least one channel of a plurality of received channels and pass through the remaining channels, at least one receiver, for receiving the at least one dropped channel from the at least one optical add/drop device, an aggregation device for assembling optical signals from the at least one receiver into original data formats, at least one transmitter for transmitting wavelength division multiplexed optical signals on the plurality of channels, a de-aggregation device for disassembling input data into blocks of data to be transmitted as optical signals by the at least one transmitter, and a controller for processing a global timing schedule.

Abstract: A multi-channel (e.g. WDM) receiver, in which l PMD compensators are time-shared by n (n>1) communication channels, where 1?l?n?1. The receiver implements PMD monitoring to identify channels exhibiting relatively high amounts of PMD. Some or all of the identified channels are then subjected, before decoding, to PMD-reduction processing, while the remaining channels are decoded without such processing. Channel allocation for the processing may be changed dynamically depending on the current amounts of PMD exhibited by various channels. Due to efficient utilization of PMD compensators, multi-channel receivers of the invention are capable of performance comparable to that of the corresponding fully compensated (i.e., having a dedicated PMD compensator for each channel) receivers, but at appreciably lower cost.

Abstract: Methods and apparatus are described for generating and receiving amplitude and differential-phase encoded signals in which the number of phase states at a given amplitude level is always less than or equal to that at a higher amplitude level and at least two amplitude levels have different numbers of phase states.

Abstract: An optical WDM-TDM network includes a plurality of devices, each of the devices including at least one optical add/drop device adapted to drop optical signals of at least one channel of a plurality of received channels and pass through the remaining channels, at least one receiver, for receiving the at least one dropped channel from the at least one optical add/drop device, an aggregation device for assembling optical signals from the at least one receiver into original data formats, at least one transmitter for transmitting wavelength division multiplexed optical signals on the plurality of channels, a de-aggregation device for disassembling input data into blocks of data to be transmitted as optical signals by the at least one transmitter, and a controller for processing a global timing schedule.

Abstract: A control circuit designed to control driving voltages applied to the actuating electrodes of a MEMS mirror. The control circuit is interfaced with a mirror position sensor and includes a variable gain amplifier whose output depends on a desired mirror equilibrium angle and a current mirror tilt angle determined by the sensor. The desired equilibrium angle can be changed by varying a reference signal applied to the amplifier. The control circuit can stabilize the mirror at relatively large tilt angles and, as a result, extend the available angular range beyond the snap-down angle. Since the number of MEMS mirrors that can be arrayed in an optical cross-connect is a function of the available angular range, the number of channels in a cross-connect may be substantially increased.

Abstract: A control circuit designed to control driving voltages applied to the actuating electrodes of a MEMS mirror. The control circuit is interfaced with a mirror position sensor and includes a variable gain amplifier whose output depends on a desired mirror equilibrium angle and a current mirror tilt angle determined by the sensor. The desired equilibrium angle can be changed by varying a reference signal applied to the amplifier. The control circuit can stabilize the mirror at relatively large tilt angles and, as a result, extend the available angular range beyond the snap-down angle. Since the number of MEMS mirrors that can be arrayed in an optical cross-connect is a function of the available angular range, the number of channels in a cross-connect may be substantially increased.

Abstract: A multi-channel (e.g. WDM) receiver, in which l PMD compensators are time-shared by n (n>1) communication channels, where 1≦l≦n−1. The receiver implements PMD monitoring to identify channels exhibiting relatively high amounts of PMD. Some or all of the identified channels are then subjected, before decoding, to PMD-reduction processing, while the remaining channels are decoded without such processing. Channel allocation for the processing may be changed dynamically depending on the current amounts of PMD exhibited by various channels. Due to efficient utilization of PMD compensators, multi-channel receivers of the invention are capable of performance comparable to that of the corresponding fully compensated (i.e., having a dedicated PMD compensator for each channel) receivers, but at appreciably lower cost.

Abstract: This invention is directed toward reducing substantially the loss incurred when two optical fibers of different mode diameters are coupled together. In this invention, the coupling of one fiber to that of another where the fibers are of different mode diameters is not with a tapered fusion, core-to-core splice, but with an evanescent field fiber coupler. Briefly, to achieve amplification of a weak optical signal, an amplifying fiber is inserted into the system at one or a plurality of locations. More specifically, at a desired location, the transmission fiber is severed to provide two sections and the severed sections are transversely coupled to the amplifying fiber. The weak signal from the first section of the transmission fiber is coupled into the amplifying fiber via a first evanescent field type of fiber coupler; and the amplified signal is coupled from the amplifying fiber to the second section of the transmission fiber via a second evanescent field type of fiber coupler.