A semiconductor laser (1) emits laser light. An electro-absorption optical modulator (2) modulates the laser light. The electro-absorption optical modulator (2) includes a plurality of electro-absorption regions (2a, 2b, 2c) having different extinction characteristics, whereby the extinction ratio curve of the optical device can be controlled to have a shape with multiple steps that is suited to driving conditions.

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.

Systems and methods for increasing throughput of a photonic processor by using photonic degrees of freedom (DOF) are provided. The photonic processor includes a multiplexer configured to multiplex, using at least one photonic DOF, multiple encoded optical signals into a multiplexed optical signal. The photonic processor also includes a detector coupled to an output of an optical path including the multiplexer, the detector being configured to generate a first current based on the multiplexed optical signal or a demultiplexed portion of the multiplexed optical signal. The photonic processor further includes a modulator coupled to and output of the detector, the modulator being configured to generate a second current by modulating the first current.

A device for generating wide capture range frequency tunable optical millimeter-wave signal includes a millimeter-wave signal generating structure, a millimeter-wave signal modulation structure, an optical delay phase detection structure and a feedback control loop. The millimeter-wave signal generating structure obtains millimeter-wave signal by beat frequency of the optical signal generated by a master laser and a slave laser, the millimeter-wave signal is modulated onto an optical carrier of the master laser by the electro-optical modulation structure, and then passes through the optical delay phase detection structure to generate an error signal associated with a frequency of the millimeter-wave signal. The error signal is controlled by the feedback control loop to change temperature and driving current of the slave laser, and adjust a difference between output wavelengths of the master laser and the slave laser, and at last maintain the frequency and phase of the millimeter-wave be stable.

An optical modulator for generating quadrature amplitude modulation (nQAM) and phase-shift keying (nPSK) signals with tunable modulation efficiency. The modulator includes a controlling circuit for adjusting the modulation efficiency or modulation depth of the modulator by controlling the direct current (DC) bias.

One example includes an optical transmitter system. The system includes a waveguide to receive and propagate an optical signal. The system also includes a ring modulation system comprising a ring resonator that is optically coupled to the waveguide and is to resonate a given wavelength of the optical signal in response to an input data signal that is provided to a modulation amplifier to provide carrier injection to change a refractive index of the ring resonator to resonate the given wavelength of the optical signal to modulate the optical signal. The system further includes a tuning controller associated with the ring modulation system. The tuning controller can implement iterative feedback tuning of the ring modulation system based on a relative amplitude of an optical intensity of the given wavelength in the ring resonator and a variable reference amplitude to substantially stabilize the ring resonator with respect to the given wavelength.

The nonlinearities of cascaded and series configurations of Mach-Zehnder electrooptic modulators are utilized to increase signal bandwidth and boost signal fidelity in electronic digital to analog converters.

A method and system for locking the resonance frequency of ring resonators by using laser sources to emit a plurality of different wavelengths, applying a tagging signal to each of the wavelengths, multiplexing the tagged wavelengths using a wavelength division multiplexor, coupling the multiplexed tagged wavelengths onto a bus waveguide, detecting the multiplexed tagged wavelengths with a first photodetector disposed before a first ring resonator and a second photodetector disposed after a last ring resonator of a plurality of ring resonators, sending the signals detected by the first and second photodetector to a processor, which identifies and processes the tagging signals, generating a control signal for each ring resonator, by the processor and applying the control signals to phase shifters on each ring resonator of the plurality of ring resonators to tune and align the resonance wavelengths of the ring resonators with the wavelengths of the corresponding laser sources.

The present disclosure provides a photonics-aided vector terahertz signal communication system. The system includes an optical frequency comb generation module, a vector terahertz signal generation module, an optical fiber transmission module, a vector terahertz signal detection module, and a vector terahertz signal emission module that are sequentially connected, where the vector terahertz signal generation module includes a first binary sequence generator, a first electronic amplifier, and a first intensity modulator that are sequentially connected, the first binary sequence generator generates binary data representing to-be-transmitted data, the first intensity modulator performs, based on the binary data, amplitude modulation on an optical frequency comb entering the first intensity modulator, and an optical signal obtained after the modulation of the first intensity modulator is a vector terahertz signal carrying the to-be-transmitted data. In the present disclosure, a vector terahertz signal can be generated by using an intensity modulator.

A method and system for locking the resonance frequency of ring resonators by using laser sources to emit a plurality of different wavelengths, applying a tagging signal to each of the wavelengths, multiplexing the tagged wavelengths using a wavelength division multiplexor, coupling the multiplexed tagged wavelengths onto a bus waveguide, detecting the multiplexed tagged wavelengths with a first photodetector disposed before a first ring resonator and a second photodetector disposed after a last ring resonator of a plurality of ring resonators, sending the signals detected by the first and second photodetector to a processor, which identifies and processes the tagging signals, generating a control signal for each ring resonator, by the processor and applying the control signals to phase shifters on each ring resonator of the plurality of ring resonators to tune and align the resonance wavelengths of the ring resonators with the wavelengths of the corresponding laser sources.