Abstract: An encoder for generating an optical data code from a symbol performs a symbol mapping and an encoding, wherein the symbol mapping performs providing a first constellation format having first and second amplitude rings with circular grids corresponding to phase angles, providing a second constellation format having the first and second amplitude rings with the circular grids corresponding to the phase angles, applying a first part of the symbol to one of the first and second constellation formats to represent the first part of the symbol by one of the first and second amplitude rings with one of the circular grids, and applying a second part of the symbol to another one of the first and second constellation formats to represent the second part of the symbol by one of the first and second amplitude rings with one of the circular grids. The first and the second constellation can be mapped to subcarrier modulation in three different ways.

Abstract: A transmitter for transmitting an encoded codeword over a communication channel is described. The transmitter includes a source to accept source data, an irregular polar encoder operated by a processor to encode the source data with at least one polar code to produce an encoded codeword, a modulator to modulate the encoded codeword, and a front end to transmit the modulated and encoded codeword over the communication channel, wherein the polar code is specified by a set of regular parameters and a set of irregular parameters.

Abstract: A receiver includes a polar decoder for decoding an encoded codeword transmitted over a communication channel. The receiver includes a front end to receive over a communication channel a codeword including a sequence of bits modified with noise of the communication channel and a soft decoder operated by a processor to produce a soft output of the decoding. The codeword is encoded by at least one polar encoder with a polar code. The processor is configured to estimate possible values of the bits of the received codeword using a successive cancelation list (SCL) decoding to produce a set of candidate codewords, determine a distance between each candidate codeword and a soft input to the soft decoder, and determine a likelihood of a value of a bit in the sequence of bits using a difference of distances of the candidate codewords closest to the received codeword and having opposite values at the position of the bit.

Abstract: A transmitter for transmitting an encoded codeword over a communication channel includes a source to accept source data, an irregular polar encoder operated by a processor to encode the source data with at least one polar code to produce the encoded codeword, a modulator to modulate the encoded codeword, and a front end to transmit the modulated and encoded codeword over the communication channel. The polar code is specified by a set of regular parameters including one or combination of parameters defining a number of data bits in the codeword, a parameter defining a data index set specifying locations of frozen bits in the encoded codeword, and a parameter defining a number of parity bits in the encoded codeword.

Abstract: A photonic device for converting optical modes of optical beams includes a first port to receive a first beam having a first mode, a mode converter and a second port to transmit the first beam. The mode converter is configured to broaden the first beam to convert the first mode into a second mode and narrow the broadened first beam at an output side of the mode converter, wherein the mode converter includes a guide material having a first refractive index and perturbation segments each having a second refractive index, wherein the first refractive index is greater than the second refractive index, wherein the perturbation segments are arranged in the guide material to cross the first beam.

Abstract: A scanner includes an emitter configured to emit a wave in a direction of propagation to penetrate layers of a structure of a target object and a receiver configured to measure intensities of the wave reflected by the layers of the target object. The scanner also includes a hardware processor configured to partition the intensities of the reflected wave into a set of segments, such that each segment is the reflection from a corresponding layer of the target object, defining a multi-layered structure of the target object; and reconstruct images of the layers of the target object from corresponding segments using a joint-layer hierarchical image recovery that prevents an increase in sparsity of the layers of the target object in the direction of propagation of the wave. An output interface is configured to render the reconstructed images of layers of the target object.

Abstract: An encoder for encoding source information into an encoded codeword used in a communication channel includes a data input to receive source data, a processor, and a memory to store an encoder program. The encoder program makes the processor to encode the source data into a turbo product coding (TPC) structure, and the TPC structure comprises a data block corresponding to the source data, a first parity block including a first column part, a first corner part and a first bottom part, the first parity block being arranged so as to cover a right end column of the data block, a right bottom corner of the data block and a bottom row of the data block by the first column part, the first corner part and the first bottom part, and a second parity block having a row parity block, a joint parity block and a column parity block.

Abstract: A method for reconstructing an uncompressed signal. The method includes obtaining an encoded signal corresponding to the signal. Obtaining side information about the signal and using the side information to obtain a prediction of dithered linear measurements of the signal. Using the prediction of the dithered linear measurements and encoded quantized dithered linear measurements to obtain quantized linear measurements of the signal based on processing each bitplane iteratively, starting from a least significant level bitplane to a most significant level bitplane. At each iteration, a prediction of each bitplane is formed using the prediction of the dithered linear measurements and the bitplanes processed in the previous iterations. Wherein each code for each bitplane is used to correct each bitplane prediction. Reconstructing the signal as a reconstructed signal using the recovered quantized dithered linear measurements, wherein the steps are performed in a processor of a decoder.

Abstract: A photonic integrated circuit having discrete optical components arranged on a top side of a substrate includes a first and second optical sources respectively configured to emit light beams, a first interferometer having a first and second input ports respectively coupled to the first and second optical sources via first waveguides, a second interferometer configured to receive signals from the first interferometer via second waveguides and combine the signals to transmit a combined signal via a third waveguide, and a submount configured to contact a back side of the substrate, wherein the submount includes a first thermal conductor having a first thermal conductivity and a second conductor having a second thermal conductivity, wherein the first thermal conductivity is greater than the second thermal conductivity, and the first and second optical sources are more proximity to the first thermal conductor than the second thermal conductor.

Abstract: A photonic integrated circuit having discrete optical components arranged on a top side of a substrate includes a first and second optical sources respectively configured to emit light beams, a first interferometer having a first and second input ports respectively coupled to the first and second optical sources via first waveguides, a second interferometer configured to receive signals from the first interferometer via second waveguides and combine the signals to transmit a combined signal via a third waveguide, and a submount configured to contact a back side of the substrate, wherein the submount includes a first thermal conductor having a first thermal conductivity and a second conductor having a second thermal conductivity, wherein the first thermal conductivity is greater than the second thermal conductivity, and the first and second optical sources are more proximity to the first thermal conductor than the second thermal conductor.

Abstract: A communication system includes a data source to receive a block of bits, a memory to store a set of distribution matchers. Each distribution matcher is associated with a probability mass function (PMF) to match equally likely input bits to a fixed number of output bits with values distributed according to the PMF of the distribution matcher. Each distribution matcher is associated with a selection probability, such that a sum of joint probabilities of all distribution matchers equals a target PMF. A joint probability of a distribution matcher is a product of PMF of the distribution matcher with the selection probability of the distribution matcher.

Abstract: A receiver includes a polar decoder for decoding an encoded codeword transmitted over a communication channel The receiver includes a front end to receive over a communication channel a codeword including a sequence of bits modified with noise of the communication channel and a soft decoder operated by a processor to produce a soft output of the decoding. The codeword is encoded by at least one polar encoder with a polar code. The processor is configured to estimate possible values of the bits of the received codeword using a successive cancelation list (SCL) decoding to produce a set of candidate codewords, determine a distance between each candidate codeword and a soft input to the soft decoder, and determine a likelihood of a value of a bit in the sequence of bits using a difference of distances of the candidate codewords closest to the received codeword and having opposite values at the position of the bit.

Abstract: A transmitter for transmitting an encoded codeword over a communication channel includes a source to accept source data, an irregular polar encoder operated by a processor to encode the source data with at least one polar code to produce the encoded codeword, a modulator to modulate the encoded codeword, and a front end to transmit the modulated and encoded codeword over the communication channel. The polar code is specified by a set of regular parameters including one or combination of parameters defining a number of data bits in the codeword, a parameter defining a data index set specifying locations of frozen bits in the encoded codeword, and a parameter defining a number of parity bits in the encoded codeword.

Abstract: A transmitter includes a plurality of antennas for beamforming with different angles of departure (AoD), an information interface to receive a sequence of symbols including a first symbol and a second symbol and a modulator to cause the plurality of antennas to form a transmission beam with an AoD selected according to a value of the first symbol and modulated according to a value of the second symbol.

Abstract: A method decodes an optical signal transmitted over an optical channel from a transmitter to a receiver. The receiver receives the transmitted optical signal to produce a digital signal which is filtered in the frequency domain for compensating static effects and/or dynamic effects. The filtering is performed in the frequency domain, while the frequency coefficients of the filter are updated in the time domain by updating at least some of time coefficients of the filter and transforming the time coefficients into the frequency domain.

Abstract: Methods and systems for decoding symbols transmitted over an optical channel having a cross-polarization modulation (XPolM) impairment, wherein an optical signal is polarized to encode the symbols on an x-polarization and an y-polarization before transmitted. The method including receiving the optical signal transmitted over the optical channel. Sampling the optical signal to produce a sequence of digital samples, wherein each digital sample includes a measurement of each polarization of the optical signal at an instance of time. Selecting a subset of the sequence of digital samples that includes a digital sample and neighboring digital samples on the sequence. Repeating the selecting and the determining for each digital sample remaining in the sequence of digital samples to produce a sequence of cross-talk coefficients; and decoding some of the symbols from the sequence of digital samples using cross-talk models with corresponding cross-talk coefficients, wherein method steps are performed using a processor.

Abstract: Methods and systems for decoding symbols transmitted over an optical channel having a cross-polarization modulation (XPolM) impairment, wherein an optical signal is polarized to encode the symbols on an x-polarization and an y-polarization before transmitted. The method including receiving the optical signal transmitted over the optical channel. Sampling the optical signal to produce a sequence of digital samples, wherein each digital sample includes a measurement of each polarization of the optical signal at an instance of time. Selecting a subset of the sequence of digital samples that includes a digital sample and neighboring digital samples on the sequence. Repeating the selecting and the determining for each digital sample remaining in the sequence of digital samples to produce a sequence of cross-talk coefficients; and decoding some of the symbols from the sequence of digital samples using cross-talk models with corresponding cross-talk coefficients, wherein method steps are performed using a processor.

Abstract: An optical waveguide interferometer that includes a first optical section, a second optical section, and a set of optical waveguides configured to connect the first and second optical sections, such that light propagating between the first optical section and the second optical section passes through each optical waveguide in the set, wherein the set of optical waveguides includes a first optical waveguide having a first length and a first width and a second optical waveguide having a second length and a second width, wherein the second length is greater than the first length, and the second width is greater than the first width.

Abstract: A method for decoding a codeword transmitted over a channel demodulates data received over the channel to produce an initial estimate of belief messages for bits of the codeword and decodes the codeword using a belief propagation (BP) decoding that iteratively passes the belief messages between a set of variable nodes representing the bits of the codeword and a set of check nodes representing parity-check constraints on the bits of the codeword until a termination condition is met. The BP decoding selects a look-up table based on a probability of the belief messages and maps, using the look-up table, values of at least two incoming belief messages to values of at least one outgoing belief message that forms an incoming belief message in a subsequent iteration of the BP decoding.

Abstract: An optical data coding method includes at least steps of selecting a modulation scheme comprising an X-polarization constellation format having first and second amplitude rings with circular grids corresponding to predetermined phase angles and a Y-polarization constellation format having the first and second amplitude rings with the circular grids corresponding to the predetermined phase angles, arranging a first part of the symbol on a first circular grid of the first amplitude ring on the X-polarization constellation format, and arranging a second part of the symbol on a second circular grid of the second amplitude ring on the Y-polarization constellation format.