An assembly (10) for generating a laser beam (12) includes a beam steering assembly (18); a laser assembly (16) that is tunable over a tunable range; and a controller (20). The laser assembly (16) generates a laser beam (12) that is directed at the beam steering assembly (18). The controller (20) dynamically controls the beam steering assembly (18) to dynamically steer the laser beam (12) as the laser assembly (16) is tuned over at least a portion of the tunable range. As a result thereof, the laser beam (12) is actively steered along a desired beam path (12A) while the wavelength of the laser beam (12) is varied.

A MEMS tunable VCSEL includes a membrane device having a mirror and a distal-side electrostatic cavity for displacing the mirror to increase a size of an optical cavity. A VCSEL device includes an active region for amplifying light. Then, one or more proximal-side electrostatic cavities are defined between the VCSEL device and the membrane device and used to displace the mirror to decrease a size of an optical cavity.

Coupled-cavity waveguide reflectors suitable for use in high-Q reflective spectral filters, narrow-linewidth lasers, and the like, are presented. Coupled-cavity waveguide reflectors in accordance with the present disclosure comprise multiple waveguide segments arranged in a series, each segment including a tooth having relatively higher refractive index and a gap having relatively lower refractive index, where the lengths of the teeth and gaps are based on the position of their respective segments in the series. The lengths of the teeth and gaps are selected such that the reflectivity of the segments align at only a single wavelength, thereby enabling very narrow-linewidth operation.

Systems and methods described herein are directed to optical light sources, such as an external cavity laser (ECL) with an active phase shifter. The system may include control circuitry for controlling one or more parameters associated with the active phase shifter. The phase shifter may be a p-i-n phase shifter. The control circuitry may cause variation in a refractive index associated with the phase shifter, thereby varying a lasing frequency of the ECL. The ECL may be configured to operate as a light source for a light detection and ranging (LIDAR) system based on generating frequency modulated light signals. In some embodiments, the ECL may generate an output LIDAR signal with alternating segments of increasing and decreasing chirp frequencies. The ECL may exhibit increased stability and improved chirp linearities with less dependence on ambient temperature fluctuations.

Narrow-optical linewidth laser generation devices and methods for generating a narrow-optical linewidth laser beam are provided. One narrow-optical linewidth laser generation devie includes a single-wavelength mirror or multiwavelength mirror (for comb lasers) formed from one or more optical ring resonators coupled with an optical splitter. The optical splitter may in turn be coupled with a quantum dot optical amplifier (QDOA), itself coupled with a phase-tuner. The phase tuner may be further coupled with a broadband mirror. The narrow-optical linewidth laser beam is generated by using a long laser cavity and additionally by using an integrated optical feedback.

A light source device includes an optical fiber; a beam light source configured to coaxially combine laser beams of different peak wavelengths to generate and emit a wavelength-combined beam; and an optical coupling device configured to allow the wavelength-combined beam emitted from the beam light source to be incident on the optical fiber. The optical coupling device includes a first cylindrical lens configured to focus the wavelength-combined beam in a first plane and having a first focal length, a second cylindrical lens configured to focus the wavelength-combined beam in a second plane and having a second focal length, and a third cylindrical lens having a third focal length greater than the first focal length and configured to focus the wavelength-combined beam in the first plane to be incident on the first cylindrical lens.

An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The quantum well active layer is doped with 0.3 to 1×10.sup.18/cm.sup.3 of n-type impurity.

A laser system for generating a narrow linewidth semiconductor light beam includes a substrate, a gain chip affixed on the substrate and configured to amplify light beam, and an optical feedback photonic chip affixed on the substrate, optically coupled to the gain chip, and configured to output light beam, which has a narrow linewidth around a resonant frequency of the optical feedback photonic chip, to the gain chip. The optical feedback photonic chip includes first and second optical gratings, a first multimode interferometer (MMI) and a second MMI optically coupled with a respective end of the first and second optical gratings, a third MMI configured to output two light beams to the first and second MMIs, respectively, through a respective waveguide. Based on receiving a respective one of the two light beams, the first MMI outputs two light beams to its respective end of the first and second optical gratings and the second MMI outputs two light beams to its respective end of the first and second optical gratings, the first and second optical gratings output second and third light beams, the second light beam, of which a linewidth is narrower than a linewidth of the third light beam, is directed to the third MMI, and an output port of the third MMI is configured to direct the second light beam to the gain chip.

An injection locking laser source is provided for an optical communications system. The injection locking laser source includes a laser cavity configured to receive an externally injected low linewidth primary light source. The laser cavity includes a cavity length, a cavity facet reflectivity, and a cavity quality factor. The injection locking laser source further includes an emitting region configured to output a secondary light source injection locked to the externally injected low linewidth primary light source at a stable detuning frequency based on a photon number, a steady-state phase, and a carrier number of the primary light source injected into the cavity.

In one embodiment of the invention, a semiconductor optical amplifier (SOA) in a laser ring is chosen to provide low polarization-dependent gain (PDG) and a booster semiconductor optical amplifier, outside of the ring, is chosen to provide high polarization-dependent gain. The use of a semiconductor optical amplifier with low polarization-dependent gain nearly eliminates variations in the polarization state of the light at the output of the laser, but does not eliminate the intra-sweep variations in the polarization state at the output of the laser, which can degrade the performance of the SS-OCT system.