A laser comprising a laser cavity formed by a first optical reflector, a gain region, a second optical reflector having a plurality of reflection peaks, and at least one optically active region. The first mirror may be a DBR or comb mirror and the second mirror may be a comb mirror. The spectral reflectance of the second optical reflector is adjusted at least partially based on an electric signal received form the optically active region such that only one reflection peak is aligned with a cavity mode formed by the first and second reflector.

A laser device includes a laser and a controller. The laser has an optical cavity that includes an active gain section and a phase shifter. The controller is configured to excite the active gain section to lase light out of the optical cavity. The controller is further configured to, while the light is being lased out of the optical cavity, modulate a refractive index of the phase shifter to shift an optical phase of lasing modes of the lased light to thereby reduce coherence of the lased light.

A QCL may include a substrate, an emitting facet, and semiconductor layers adjacent the substrate and defining an active region. The active region may have a longitudinal axis canted at an oblique angle to the emitting facet of the substrate. The QCL may include an optical grating being adjacent the active region and configured to emit one of a CW laser output or a pulsed laser output through the emitting facet of substrate.

A laser structure comprising a first photonic crystal surface emitting laser (PCSEL), a second PCSEL, and a coupling region that extends between the first PCSEL and the second PCSEL along a longitudinal axis and that is electrically controllable so as to be capable of coherently coupling the first PCSEL to the second PCSEL. Each PCSEL include an active layer, a photonic crystal, and a two-dimensional periodic array distributed in an array plane parallel to the longitudinal axis within the photonic crystal where the two-dimensional periodic array is formed of regions having a refractive index that is different to the surrounding photonic crystal.

A laser comprising a laser cavity formed by a first optical reflector, a gain region, a second optical reflector having a plurality of reflection peaks, and at least one optically active region. The first mirror may be a DBR or comb mirror and the second mirror may be a comb mirror. The spectral reflectance of the second optical reflector is adjusted at least partially based on an electric signal received form the optically active region such that only one reflection peak is aligned with a cavity mode formed by the first and second reflector.

A semiconductor laser and a photonic nonlinear circuit chip are integrated together. The nonlinear circuit chip may include a nonlinear waveguide configured or controlled to enable sum-frequency generation, difference-frequency generation, second-harmonic generation, parametric amplification, or other nonlinear processes. Coupling between the semiconductor laser and the nonlinear circuit may be optimized by mode-matching, while back-reflections are minimized by diverting the reflections so that optical isolators are not needed. The integration of the semiconductor laser and the nonlinear photonic circuit chip enables nonlinear optical processing using a compact and scalable platform in a flexible manner that is compatible with different types of semiconductor lasers and different operation regimes. An additional input is provided so users can input an optical signal into the photonic chip for processing therein. In some examples, the photonic chip is configured with pump resonators, such as racetrack resonators. Method and device examples are described herein.

A light emitting device has a first mirror; and one or more active regions with a first active region adjacent to the first mirror. Each of active region includes quantum wells and barriers, and is surrounded by one or more p-n junctions. The active regions have a selected shape structure each with a tunnel junction (TJ). One or more apertures are provided with the selected shape structure; one or more buried tunnel junctions (BTJ), additional TJ's, planar structures and/or additional BTJ's, created during a regrowth process that is independent of a first growth process of the first mirror as well as the active region and the one or more TJs. One or more electrical confinement apertures are defined by the one or more BTJ's, additional TJ's, planar structures and/or additional BTJ's. A vertical resonator cavity is disposed over the electrical confinement aperture. A high contrast grating (HCG) operates as a second mirror positioned over the vertical resonator cavity. The HCG is configured to reflect a first portion of light back into the vertical resonator cavity, and a second portion of the light as an output beam from the VCSEL. The HCG structure is layered on the selected shape structure. A shape of the output beam of the light emitting device is determined by a geometric shape of the one or more BTJ apertures, apertures for additional TJ's, planar structures and/or additional BTJ's, with a transmission function of the HCG. The shape is designed according to the desired optical transmission function of the application.

A surface emitting laser includes: multiple active layers; a resonator including a tunnel junction between the multiple active layers; multiple reflectors sandwiching the resonator between the multiple reflectors; and an electrode pair connected to a power supply device through which a current is injected into the multiple active layers. The surface emitting laser does not oscillate a laser beam during a current injection period in which the power supply device injects the current into the multiple active layers through the electrode pair; and oscillates the laser beam during a current decrease period after the current injection period. The current injected into the multiple active layers during the current decrease period is lower than the current injected into the multiple active layers during the current injection period.

A lithium niobate (LN) external cavity includes a Vernier mirror structure which includes two or more microresonators where: one or more or all of the Vernier microresonators are tuned by the electro-optic Pockels effect of LN, with tuning electrodes integrated with the resonators, and one of the Vernier microresonators could be tuned by the thermo-optic effect, with a local heater integrated with the resonator. One or more or all of the Vernier microresonators include a section or the whole resonator that is periodically poled to achieve quasi-phase matching for nonlinear frequency conversion directly inside the laser cavity. The lithium niobate (LN) external cavity also includes a phase shifter whose phase is tuned by the electro-optic Pockels effect of LN. A Sagnac loop mirror is placed at the end of the device to function as the output end mirror of the laser cavity.

Solid-state optical devices (10) enable tuning of an electrically tunable depletion region (200) to reduce and block lateral (in-junction) carrier spreading. This capability reduces the negative effects of gain-guiding in the junction plane and reduces an astigmatism of an emitted light beam. The tunable depletion region is created by forming a highly resistive Schottky contact (105, 110) or metal-insulator-semiconductor (MIS) structure (205, 210) next to a waveguide (optical mode propagation) and current injection region (215), where lateral spread due to diffusion is expected. The depletion region area is tuned by applying a bias to the highly resistive Schottky contact or the MIS contact structure. Such contacts or similar lossy structures reduce in-junction plane gain-guiding also when unbiased by creating additional optical loss for the mode, thus reducing the effective carrier density participating in light generation, thereby reducing astigmatism.