An apparatus includes a plurality of VCSELs, a master laser, one or more electrical drivers, and an optical combiner. The master laser is configured to transmit laser light to the VCSELs to optically lock wavelengths of the VCSELs. The one or more electrical drivers are connected to directly electrically modulate the VCSELs in a manner responsive to one or more digital data stream. The optical combiner is configured to combine light received from, at least, a pair of the VCSELs into an optical carrier with a substantially phase digital data modulation.

An FM LIDAR system is described that includes a frequency modulated LIDAR system that incorporates a laser source that is optically coupled to a whispering gallery mode optical resonator. Light from the laser that is coupled into the whispering gallery mode optical resonator is coupled back out as a returning counterpropagating wave having a frequency characteristic of a whispering gallery mode of the optical resonator. This returning wave is used to reduce the linewidth of the source laser by optical injection. Modulation of the optical properties of the whispering gallery mode optical resonator results in modulation of the frequency of the frequencies supported by whispering gallery modes of the resonator, and provides a method for producing highly linear and reproducible optical chirps that are highly suited for use in a LIDAR system. Methods of using such an FM LIDAR system and vehicle assisting systems that incorporate such FM LIDAR systems are also described.

A narrow linewidth laser in which an all-optical feedback line-up is used to improve the linewidth from a conventional laser source, such as a laser diode. The feedback line-up comprises an optical device having a controllable unbalanced optical coupler arranged on a cavity input path to couple a source signal from the laser source into the optical cavity, and to couple a seed signal received back from the optical cavity into the laser source. The seed signal has a lower power than the source signal. The unbalanced optical coupler may be an optical isolator arranged to couple the seed signal into the laser source at a power level selected to promote preferential stimulated emission within a narrower linewidth. By controlling the power of seed signal such that only a small portion thereof influences the lasing cavity, the narrowing effect of the preferential stimulated emission can be enhanced.

Apparatus and methods for altering one or more spectral, spatial, or temporal characteristics of a light-emitting device are disclosed. Generally, such apparatus may include a volume Bragg grating (VBG) element that receives input light generated by a light-emitting device, conditions one or more characteristics of the input light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light.

A light pulse source and method for generating repetitive optical pulses are described. The pulse source includes a continuous wave (cw) laser device, an optical waveguide optically coupled with the laser device, an optical microresonator, and a tuning device. The optical microresonator coupling cw laser light via the waveguide into the microresonator, which may include a light field in a soliton state with soliton shaped pulses coupled out of the microresonator for providing the repetitive optical pulses. The laser device includes a chip based semiconductor laser, the microresonator and/or the waveguide may reflect an optical feedback portion of light back to the semiconductor laser, which may provide self-injection locking relative to a resonance frequency of the microresonator. The tuning device is arranged for tuning at least one of a driving current and a temperature of the semiconductor laser such that the microresonator may provide the soliton state.

An optoelectronic oscillator for generating an optical and/or electric pulse comb, comprising a monolithically integrated passively mode-coupled semiconductor laser and an optical feedback loop which guides a part of the optical radiation of the semiconductor laser and feeds said part back into the semiconductor laser as feedback pulses. Without the influence of the feedback pulses, the semiconductor laser would emit comb-like optical pulses, hereafter referred to as primary pulses, and in the event of an influence, emits comb-like output pulses which have been influenced by the feedback pulses, said output pulses having a lower temporal jitter or less phase noise than the primary pulses. The feedback loop is damped between 27.5 and 37.5 dB, and the time lag of the feedback loop is selected such that each feedback pulse is incident within the temporal half-value width of each subsequent primary pulse.

A sensor system includes a self-mixing interferometry sensor; a drive circuit configured to apply a modulated drive signal to an input of the self-mixing interferometry sensor; a mixer circuit configured to mix a modulated output of the self-mixing interferometry sensor with a local oscillator signal that is orthogonal to the modulated drive signal over a period of time; an integrator circuit configured to integrate an output of the mixer circuit over the period of time; and a processor configured to determine, using an output of the integrator circuit, at least one of a round-trip propagation time of electromagnetic radiation emitted by the self-mixing interferometry sensor and reflected back into the self-mixing interferometry sensor by an object or medium, or a velocity of the object or medium.

A non-reciprocal optical assembly for injection locking a laser to a resonator is described. The laser emits a light beam, and the resonator receives the light beam and returns a feedback light beam to the laser such that the feedback light beam causes injection locking. The non-reciprocal optical assembly is interposed between and optically coupled to the laser and the resonator. The non-reciprocal optical assembly includes a first port that receives the light beam from the laser, and a second port that outputs the light beam to the resonator and receives the feedback light beam from the resonator. The first port also outputs the feedback light beam to the laser. The light beam passes through the non-reciprocal optical assembly with a first power loss, and the feedback light beam passes through the non-reciprocal optical assembly with a second power loss (the first power loss differs from the second power loss).

Methods, systems, and apparatus, for optical communication. One apparatus includes a Fabry-Perot (FP) laser diode assembly coupled to a first port of a circulator; an optical amplifier coupled to a second port of the circulator; a wavelength division multiplexer (WDM) filter coupled to a third port of the circulator; and a Faraday rotator mirror coupled to the WDM filter.

A method of performing spectroscopic measurements provides an optical frequency comb, and directs the comb through or at a sample. The optical frequency comb is generated by gain switching a laser diode constructed from Gallium Nitride and related materials. Various techniques are described for manipulating the comb source to achieve desired benefits for spectroscopy.