An optical network includes a transmitter portion configured to (i) precode an input digitized stream of symbols into a precoded symbol stream, (ii) pulse shape the precoded symbol stream with an eigenvalue channel matrix, and (iii) transmit the pulse shaped symbol stream over a digital optical link. The optical network further includes a receiver portion configured to (i) recover the pulse shaped symbol stream from the digital optical link, (ii) decompose eigenvalues of the eigenvalue channel matrix from the recovered symbol stream, and (iii) decode the decomposed symbol stream into an output symbol stream.

An optical signal receiver includes a processor, a memory, an input, an output, and a sampling unit in operable communication with the processor and the memory. The sampling unit includes a shift register and a clock, and is configured to receive a laser signal at the input, collect a first sample of the received input laser signal at a first time interval, determine an amplitude of the first sample, assign a first symbol of a plurality of symbols to the determined amplitude, insert the first symbol at a first insertion point within the shift register, and generate a delay value at the output based on a position of the first insertion point with respect to the output.

Methods and apparatus for interference cancelation in a radio frequency communications device are described. In various embodiments a signal to be transmitted in converted into an optical signal and processed using an optical filter assembly including one or more optical filters to generate an optical interference cancelation signal. The optical interference cancelation signal is converted into an analog radio frequency interference cancelation signal using an optical to electrical converter prior to the analog radio frequency interference cancelation signal being combined with a received signal to cancel interference, e.g., self interference. The optical filter assembly can include a large number of taps, e.g., 30, 50, 100 or more. Each tap may be implemented as a separate optical filter or series of optical filters. Delays and/or gain of the optical filters can be controlled dynamically based on channel estimates which may change due to changes in the environment and/or communications device position.

The present invention relates to an optical noise removal circuit, an optical receiver, and an optical chip. The optical noise removal circuit includes: a noise filter unit, where an input end of the noise filter unit receives an electrical signal coming from an photoelectric conversion unit, and the noise filter unit is configured to filter out a noise electrical signal, in the electrical signal, that is generated due to ambient light, and output a target pulse signal at an output end; and a comparison unit, where a first input end of the comparison unit is coupled to the output end of the noise filter unit to receive the target pulse signal, and the comparison unit is configured to output a digital signal based on comparison between the target pulse signal and a reference voltage. By implementing the present invention, quality of a received optical signal can be effectively improved.

The present disclosure provides an optical signal receiving apparatus, an optical line terminal, an optical signal receiving system, an optical signal receiving method, and a computer-readable storage medium. The optical signal receiving apparatus includes: a first filter configured to perform wavelength division processing on original optical signals, and perform at least one of following operations: outputting at least one of a first optical signal corresponding to a first wavelength range or a second optical signal corresponding to a second wavelength range; an amplifier configured to amplify the first optical signal; a second filter configured to receive the amplified first optical signal, and perform noise reduction processing on the amplified first optical signal; and the detection element is configured to receive and convert at least one of the first optical signal subjected to the noise reduction processing or the second optical signal into a transmission electrical signal.

High-performance ultra-wideband Receive Phased Array Sensors (Rx-PAS) are disclosed, which have unique capabilities, enabled through photonic integrated circuits and novel optical architectures. Unique capabilities for a Rx-PAS are provided by wafer scale photonic integration including heterogeneous integration of III-V materials and ultra-low-loss silicon nitride waveguides. Novel aspects include optical multiplexing combining wavelength division multiplexing and/or a novel extension to array photodetectors providing the capability to combine many RF photonic signals with very low loss. The architecture includes tunable optical down-conversion, moving a chosen frequency band to baseband with high dynamic range; creating also a single frequency hand channelizer, which is also expanded to create a multiple tunable frequency band channelizer. Simultaneous multi-channel beamforming is achieved through optical power splitting of optical signals to create multiple exact replicas of the signals that are then processed independently.

Methods and apparatus for interference cancelation in a radio frequency communications device are described. In various embodiments a signal to be transmitted in converted into an optical signal and processed using an optical filter assembly including one or more optical filters to generate an optical interference cancelation signal. The optical interference cancelation signal is converted into an analog radio frequency interference cancelation signal using an optical to electrical converter prior to the analog radio frequency interference cancelation signal being combined with a received signal to cancel interference, e.g., self interference. The optical filter assembly can include a large number of taps, e.g., 30, 50, 100 or more. Each tap may be implemented as a separate optical filter or series of optical filters. Delays and/or gain of the optical filters can be controlled dynamically based on channel estimates which may change due to changes in the environment and/or communications device position.

According to one embodiment of the present invention, an apparatus and method for transmitting and receiving signals in a wireless communication system comprise receiving an optical signal including an interference signal and a target signal, attenuating the interference signal, and converting the optical signal in which the interference signal is attenuated, into electric signals via a photodiode array, wherein a transceiver comprises a first optical filter upon which the optical signal is incident, and a second optical filter upon which the optical signal having passed through the first optical filter is incident, wherein the interference signal may be attenuated through the first optical filter and the second optical filter.

A channel estimation technique suitable for implementation at a digital communication receiver such as an optical signal receiver apparatus includes receiving, over a communication channel, a transmission comprising a sequence of modulated symbols, estimating, at multiple frequencies, estimated values of a channel transfer function of the communication channel and selectively revising the estimated values of channel transfer function by reducing glitches in the estimated values of the channel transfer function.

High-performance ultra-wideband Receive Phased Array Sensors (Rx-PAS) are disclosed, which have unique capabilities, enabled through photonic integrated circuits and novel optical architectures. Unique capabilities for a Rx-PAS are provided by wafer scale photonic integration including heterogeneous integration of III-V materials and ultra-low-loss silicon nitride waveguides. Novel aspects include optical multiplexing combining wavelength division multiplexing and/or a novel extension to array photodetectors providing the capability to combine many RF photonic signals with very low loss. The architecture includes tunable optical down-conversion, moving a chosen frequency band to baseband with high dynamic range; creating also a single frequency band channelizer, which is also expanded to create a multiple tunable frequency band channelizer. Simultaneous multi-channel beamforming is achieved through optical power splitting of optical signals to create multiple exact replicas of the signals that are then processed independently.