Methods and systems for encoding multi-level pulse amplitude modulated signals using integrated optoelectronics are disclosed and may include generating a multi-level, amplitude-modulated optical signal utilizing an optical modulator driven by first and second electrical input signals, where the optical modulator may configure levels in the multi-level amplitude modulated optical signal, drivers are coupled to the optical modulator; and the first and second electrical input signals may be synchronized before being communicated to the drivers. The optical modulator may include optical modulator elements coupled in series and configured into groups. The number of optical modular elements and groups may configure the number of levels in the multi-level amplitude modulated optical signal. Unit drivers may be coupled to each of the groups. The electrical input signals may be synchronized before communicating them to the unit drivers utilizing flip-flops. Phase addition may be synchronized utilizing one or more electrical delay lines.

Disclosed herein are optical transceivers with multi-laser modules, as well as related optoelectronic assemblies and methods. In some embodiments, an optical transceiver may include: a first laser and a second laser; an optical output path, wherein an output of the first laser is coupled to the optical output path; and switching circuitry to decouple the output of the first laser from the optical output path and to couple an output of the second laser to the optical output path.

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 communication system includes a plurality of optical transmitters, a plurality of first optical couplers provided respectively corresponding to the plurality of optical transmitters, a plurality of optical receivers, and a plurality of second optical couplers provided respectively corresponding to the plurality of optical receivers, in which each of the plurality of first optical couplers splits an optical signal transmitted by the corresponding optical transmitter and outputs the optical signal to each of the plurality of second optical couplers, each of the plurality of second optical couplers merges a plurality of optical signals output from the plurality of first optical couplers and outputs the merged signal to the corresponding optical receiver, and the plurality of optical transmitters alternately transmits the optical signals.

An optical modulator comprises, as optical modulator components, first and second transmitter chains and a first optical time division multiplex, OTDM, generator arranged to receive time interleaved optical pulses generated by one of said optical modulator components.

An integrated transmitter chip comprising: at least one input port disposed at a first end; a first variable power divider optically connected to a first input port of the at least one input port, the first variable power divider being tunable to a first splitting ratio; a second and a third variable power dividers each optically connected to the first variable power divider, the second and the third variable power dividers being tunable to a second and a third splitting ratios; and a first and a second optical channels being optically branched from the second variable power divider, and a third and a fourth optical channels being optically branched from the third variable power divider; wherein an optical signal being launched into the first input port and having an input power is caused to be split by the first variable power divider into a first and a second optical signals.

An optical transmitter includes an I-component optical modulation unit, a Q-component optical modulation unit, and a 2×2 optical coupler. The I-component optical modulation unit generates modulated light based on an I-component data signal. The Q-component optical modulation unit generates modulated light based on a Q-component data signal. The 2×2 optical coupler receives the modulated light generated by the I-component optical modulation unit from a first input port, receives the modulated light generated by the Q-component optical modulation unit from a second input port, generates two optical QAM signals having a phase conjugate relationship from the modulated light which has been input from the first input port and the modulated light which has been input from the second input port, outputs one of said two optical QAM signals from a first output port, and outputs the other one of said two optical QAM signals from a second output port.

An optical transmission system includes an optical transmitter and an optical receiver. The optical transmitter includes a low speed signal generation unit configured to generate, based on an input signal of a transmission data sequence and a signal obtained by cyclically shifting a spectrum of the input signal, a plurality of low speed signals, a high speed signal generation unit configured to digital-to-analog convert and synthesize the plurality of low speed signals to generate a high speed signal, and an optical modulation unit configured to transmit an optical signal obtained by modulation of the high speed signal to a transmission path. The optical receiver includes a reception unit configured to receive the optical signal from the transmission path and output the high speed signal obtained from the optical signal that is received, an optical-receiver-side high speed signal compensation unit configured to compensate, based on the high speed signal output by the reception unit and a signal obtained by cyclically shifting a spectrum of the high speed signal, for the high speed signal, and a reception data decoding unit configured to decode the high speed signal compensated by the optical-receiver-side high speed signal compensation unit to restore binary information included in the optical signal transmitted by the optical transmitter.

Consistent with the present disclosure, a local oscillator is provided in a receiver. The local oscillator laser a first and second mirrors and phase section and heaters are provided adjacent each portion of the laser, such that the temperature and thus the frequency of light output from the local oscillator laser may be tuned. Applying electrical power, such as a current or voltage to the phase section may result in rapid frequency tuning of light output from the local oscillator laser but over a limited frequency range. Temperature changes to the mirror sections, however, may afford frequency tuning over a wider range, but frequency tuning the mirror sections requires more time than that required to tune the phase section. Consistent with the present disclosure, a tuning method and apparatus is provided that optimizes laser tuning by selectively tuning the phase and mirror sections.

Methods and systems for a distributed optical transmitter with local domain splitting are disclosed and may include, in an optical modulator integrated in a silicon photonics chip: receiving electrical signals, communicating the electrical signals to domain splitters along a length of waveguides of the optical modulator via one or more delay lines, and generating electrical signals in voltage domains utilizing the domain splitters for modulating the optical signals in the waveguides of the optical modulator by driving diodes with the electrical signals generated in the voltage domains. The delay lines may comprise one delay element per domain splitter, or may comprise a delay element per domain splitter for a first subset of the domain splitters and more than one delay element per domain splitter for a second subset of the domain splitters.