Systems and methods for controlling optical feedback in an optical system. A resonant optical cavity includes at least two cavity mirrors, one of which is a cavity coupling mirror, and has a plurality of optical resonance cavity modes. A radiation source emits a beam of continuous wave radiation and is capable of being scanned whereby a mean optical frequency of the continuous wave radiation beam is adjustable over a range of frequencies, wherein the radiation source is responsive to optical feedback radiation emerging from the cavity, and wherein the mode matching optics couples the beam of continuous wave radiation to the cavity via the cavity coupling mirror. The radiation source and the mode matching optics are aligned so that a mode fill ratio is reduced relative to a maximum mode fill ratio, wherein the laser beam is coupled with a fundamental cavity mode.

To realize a reservoir computing system with a small size and reduced learning cost, provided is a laser apparatus including a laser; a feedback waveguide that is operable to feed light output from the laser back to the laser; an optical splitter that is provided in a path of the feedback waveguide and is operable to output a portion of light propagated in the feedback waveguide to outside; and a first ring resonator that is operable to be optically connected to the feedback waveguide, as well as a reservoir computing system including this laser apparatus.

A criterion method of GCCS (Globally Complete Chaos Synchronization) for three-node VCSEL (Vertical Cavity Surface Emitting Laser) networks with delay coupling is provided, including steps of: providing a delay-coupled VCSEL network consisting of three identical units and dynamic equations of the VCSEL network; providing assumptions of an outer-coupling matrix and a unitary matrix under the dynamic equations of the VCSEL network; in the three-node VCSEL network, determining rate equations of i-VCSEL, determining dynamic equations of a synchronization manifold, and determining a master-stability equation; calculating three maximum Lyapunov exponents; determining a stability of a synchronization state of the three-node VCSEL network, and determining whether the synchronization manifold of the VCSEL network is a chaotic waveform. Through a master-stability function, the method for determining whether the GCCS is achieved among all node lasers is provided, which solves a difficult problem of GCCS criterion for the VCSEL networks.

An optical path test system includes a return light test unit for emitting laser light to an optical path monitoring unit to simulate return light received by the optical path monitoring unit in a normal operation; a light path monitoring unit arranged on a light path of the return light testing unit for receiving the return light and normally emitting laser light; and a power detector for receiving the laser light emitted by the light path monitoring unit so as to monitor stability of output power of the chip when the light path monitoring unit receives the return light emitted by the return light testing unit. The technical solution in the present invention emits laser light to a tested laser chip to simulate return light received by the tested laser chip in a normal operation, and a return light resistance threshold of the laser chip can be accurately evaluated.

In an example, a tandem pumped fiber amplifier may include a seed laser, a first section coupled to an output of the seed laser, and a second section coupled to an output of the first section. The first section may operate as an oscillator, and may receive pump light from one or more diode pumps, and may the first section may be arranged to convert the one or more diode pumps into a tandem pump. The second section may operate as a power amplifier, and may include a length of a single or plural active core fiber. The tandem pumped fiber amplifier may be arranged to mitigate spectral broadening related to four-wave mixing.

In one embodiment, a light source is configured to emit an optical signal. The light source includes a seed laser diode configured to produce a seed optical signal and a semiconductor optical amplifier (SOA) configured to amplify the seed optical signal to produce the emitted optical signal. The light source also includes an optical isolator disposed between the seed laser diode and the SOA, where the optical isolator is configured to (i) transmit the seed optical signal to the SOA and (ii) reduce an amount of light that propagates from the SOA toward the seed laser diode.

In one embodiment, a light source is configured to emit an optical signal. The light source includes a seed laser diode configured to produce a seed optical signal and a semiconductor optical amplifier (SOA) configured to amplify the seed optical signal to produce the emitted optical signal. The SOA includes an optical waveguide extending along a longitudinal direction from an input end of the SOA to an output end of the SOA. The optical waveguide is configured to guide and provide optical gain to the seed optical signal while the seed optical signal propagates in the longitudinal direction along the optical waveguide from the input end to the output end. The SOA also includes a Bragg grating disposed parallel to the optical waveguide, where the Bragg grating includes a region of the SOA having a refractive index that varies along the longitudinal direction.

In one embodiment, a lidar system includes a light source configured to emit an output optical signal and a local-oscillator optical signal. The output optical signal includes (i) pulses of light and (ii) frequency-modulated (FM) output-light signals, where each pair of consecutive pulses of light is separated in time by one or more of the FM output-light signals. The local-oscillator optical signal includes FM local-oscillator light signals corresponding to the FM output-light signals. The lidar system also includes a receiver configured to detect the local-oscillator optical signal and an input optical signal. The input optical signal includes (i) a received pulse of light that includes a portion of one of the emitted pulses of light scattered by a target located a distance from the lidar system and (ii) a received FM light signal that includes a portion of one of the FM output-light signals scattered by the target.

Disclosed herein are electronic devices having touch input surfaces. A user's touch input or press on the touch input surface is detected using a set of lasers, such as vertical-cavity surface-emitting lasers (VCSELs) that emit beams of light toward the touch input surface. The user's touch causes changes in the self-mixing interference within the VCSEL of the emitted light with reflected light, such as from the touch input surface. Deflection and movement (e.g., drag motion) of the user's touch is determined from detected changes in the VCSELs' operation due to the self-mixing interference.

A modulated light source includes an FP laser that emits light in a plurality of Fabry-Perot (FP) modes, a band-pass filter whose center wavelength can be modulated, a light reflector that selectively feeds only light having passed through the modulation filter back to the FP laser, and a wavelength adjustment mechanism that adjusts the center wavelength so as to coincide with one of the predetermined FP mode when the light fed back to the FP laser is used as seed light for stimulated emission of radiation to cause selective light emission at an oscillation wavelength.