An optical transmitter device (14) includes a digital signal processor ‘DSP’ (20) having digital hardware (30). The DSP is operative to generate (102,202,302) shaped bits from a first set of information bits, and to apply (104,204,304) a systematic forward error correction ‘FEC’ scheme to encode the shaped bits and a second set of information bits, where the first set of information bits and the second set of information bits are disjoint sets. Unshaped bits and the shaped bits are mapped to selected symbols or are used to select symbols from one or more constellations. The selected symbols are mapped to physical dimensions. Each unshaped bit is either one of the second set of information bits or one of multiple parity bits resulting from the FEC encoding. In this manner, a target spectral efficiency is achieved.

An optical modulation method and device capable of stably generating an optical signal including a zero-intensity state among four states required for phase-time coding scheme by a nested modulator, is provided. A controller controls the phase difference generated by the phase shifter and an intensity and a magnitude of phase modulation provided by each of the first modulator and the second modulator to change an output lightwave of the nested modulator between four constellation points (S1-S4) on IQ plane. A first constellation point (S4) of the four constellation points has an intensity of 0, a second constellation point (S1) has a relative intensity of 1, each of a third constellation point (S2) and a fourth constellation point (S3) has a relative intensity ranging from 0 to 1, and the third and the fourth constellation points has a phase difference of 90 degrees.

An optical full-field transmitter for an optical communications network includes a primary laser source configured to provide a narrow spectral linewidth for a primary laser signal, and a first intensity modulator in communication with a first amplitude data source. The first intensity modulator is configured to output a first amplitude-modulated optical signal from the laser signal. The transmitter further includes a first phase modulator in communication with a first phase data source and the first amplitude-modulated optical signal. The first phase modulator is configured to output a first two-stage full-field optical signal. The primary laser source has a structure based on a III-V compound semiconductor.

A ternary phase shift keying transmitter and receiver can efficiently communicate using ternary encoded data that avoids indistinguishable transition curves for each of the three modulated states in the ternary encoded data. The transmitter is interoperable and can function with different types of receivers including direct detection-based receivers and coherent detection-based receivers.

Systems and methods for predicting performance of a modulation system are provided. A neural network model is trained using performance information of a source system. The neural network model is modified with transferable knowledge about a target system to be evaluated. The neural network model is tuned using specific characteristics of the target system to create a source-based target model. The target system performance is evaluated using the source-based target model to predict system performance of the target system.

A key generation method includes modulating a first key to a first light source signal, to obtain a modulated optical signal, splitting the modulated optical signal, to obtain a first sub modulated optical signal and a second sub modulated optical signal, attenuating the first sub modulated optical signal such that a quantity of photons included in each period of the first sub modulated optical signal is less than a preset value, and sending an attenuated first sub modulated optical signal to a receive-end device, and obtaining a second key carried in the second sub modulated optical signal, and storing the second key.

The present disclosure relates to a method for transmitting or receiving a signal by a reception device in a wireless communication system, and the method may comprise the steps of: receiving, from a transmission device, a signal modulated on the basis of a differential phase shift keying (DPSK) scheme; converting the received signal into an input signal of a spiking neural network (SNN); calculating an output value through the spiking neural network previously learned; and converting the output value into an input signal of a channel decoder.

An optical full-field transmitter for an optical communications network includes a primary laser source configured to provide a narrow spectral linewidth for a primary laser signal, and a first intensity modulator in communication with a first amplitude data source. The first intensity modulator is configured to output a first amplitude-modulated optical signal from the laser signal. The transmitter further includes a first phase modulator in communication with a first phase data source and the first amplitude-modulated optical signal. The first phase modulator is configured to output a first two-stage full-field optical signal. The primary laser source has a structure based on a III-V compound semiconductor.

Amplitude-modulated (AM) signals spanning a spatial wide area can be efficiently detected using a slowly scanning optical system. The system decouples the AM carrier from the AM signal bandwidth (or carrier uncertainty), enabling Nyquist sampling of only the information-bearing AM signal (or the known frequency bandwidth). The system includes a staring sensor with N pixels (e.g., N>10.sup.6) that searches for a sinusoidal frequency of unknown phase and frequency, perhaps constrained to a particular band by a priori information about the signal. Counters in the sensor pixels mix the detected signals with local oscillators to down-convert the signal of interest, e.g., to a baseband frequency. The counters store the down-converted signal for read out at a rate lower than the Nyquist rate of AM signal. The counts can be shifted among pixels synchronously with the optical line-of-sight for scanning operation.

A system and method for wavelength detection includes one or more detection stages configured for receiving at least a portion of an optical carrier. Each stage includes a splitter for splitting the signal into two arms. A 90-degree optical hybrid and in-phase (I-channel)/quadrature (Q-channel) differential detectors generate I-channel and Q-channel differential signals based on the hybrid outputs. A gas cell or like multi-point wavelength reference path also receives the input signal and provides a set of reference absorption wavelengths converted into the electrical domain by a reference photodetector. A logic device receives sets of detection signals (including I-channel and Q-channel differential signals and the set of reference wavelengths, all corresponding to a common measurement time) and determines a wavelength of the optical carrier based on an arctangent of a ratio of the Q-channel and I-channel differential signals, mapped to the set of reference absorption wavelengths.