A lidar device, comprising a laser generator and a lidar unit, is provided and operated with frequency modulation continuous wave. The laser generator comprises an amplifier unit; and a reflector unit connected with at least one end of the amplifier unit. The amplifier unit comprises at least one first luminous gain area and at least one second luminous gain area. The first luminous gain area is operated in a saturated region with a first current source applied. The second luminous gain area is operated in a linear region with a second current source applied. Thus, a laser is generated and outputted to the lidar unit. The laser generator is operated with the luminous gain areas of the amplifier unit pushed into the saturated region to suppress intensity modulation and fix power. Even if current changes, frequency drifts only with continuity and adjustability achieved and no mode hop happened.

A laser device includes: a substrate formed from material transparent at a laser wavelength; a first reflecting layer to reflect at least some incident radiation at the laser wavelength; a layer including a gain medium for providing stimulated emission of radiation at the laser wavelength, and positioned between the first reflecting layer and the substrate; a second reflecting layer on an opposite side of the substrate from the first reflecting layer to reflect at least some incident radiation at the laser wavelength; a spatial light modulator in an optical cavity comprising the first and second reflecting layers, and comprising an array of elements each corresponding to a different path for radiation in the optical cavity; and a computer controller that, during operation, causes the spatial light modulator to selectively vary an intensity or phase of radiation in the optical cavity to provide variable transverse spatial mode output of the radiation.

The present disclosure relates to a diode laser having reduced beam divergence. Some implementations reduce a beam divergence in the far field by means of a deliberate modulation of the real refractive index of the diode laser. An area of the diode laser (e.g., the injection zone), may be structured with different materials having different refractive indices. In some implementations, the modulation of the refractive index makes it possible to excite a supermode, the field of which has the same phase (in-phase mode) under the contacts. Light, which propagates under the areas of a lower refractive index, obtains a phase shift of π after passing through the index-guiding trenches. Consequently, the in-phase mode is supported and the formation of the out-of-phase mode is prevented. Consequently, the laser field can, in this way, be stabilized even at high powers such that only a central beam lobe remains in the far field.

A semiconductor laser diode includes a semiconductor body having an emitter region; and a first connection element that electrically contacts the semiconductor body in the emitter region, wherein the semiconductor body is in contact with the first connection element in the emitter region, and at least in places in the emitter region, the semiconductor body has a structuring that enlarges a contact area between the semiconductor body and the first connection element.

Laser Side Mode Suppression Ratio (SMSR) control is provided via a logic controller configured to measure an SMSR of a carrier wave upstream of a modulator and measure an Average Optical Power (AOP) of the carrier wave downstream of the modulator; transmit a bias voltage based on the SMSR and the AOP to a laser driver for a laser generating the carrier wave; and transmit an attenuation level based on the SMSR and the AOP to a Variable Optical Attenuator (VOA) upstream of the modulator. In various embodiments the attenuation level and bias voltage can rise or fall together, or one may rise and one may fall to ensure the output optical signal meets specified SMSR and AOP values.

A semiconductor laser device with external resonator with stable longitudinal mode regardless of variation of drive current is disclosed. The device includes: a semiconductor light-emitting element having a pair of end faces with a light emitting section disposed therebetween, and an external resonator configured to oscillate light emitted from the semiconductor light-emitting element, the external resonator being formed by a resonator mirror disposed outside the semiconductor light-emitting element and one of the pair of end faces that is farther from the resonator mirror, wherein, as the semiconductor light-emitting element, a semiconductor light-emitting element having a structure which does not oscillate light emitted therefrom by itself is used. The device further includes a wavelength control element disposed in the optical path within the external resonator and configured to select a wavelength range of the light, and a driver circuit configured to perform fast modulation drive of the semiconductor light-emitting element.

A control circuit in this laser equipment drives a drive circuit of a photonic crystal laser element under a predetermined condition. It was found that a wavelength width of a laser beam to be output from the photonic crystal laser element is dependent on a standardized drive current k and a pulse width T, and had a predetermined relationship with these. By meeting this condition, a laser beam with a plurality of wavelengths can be controlled and output.

An optical source is described. This optical source includes a semiconductor optical amplifier (with a semiconductor other than silicon) that provides an optical gain medium and that includes a reflector. Moreover the hybrid external cavity laser includes a photonic chip with: an optical waveguide that conveys an optical signal output by the semiconductor optical amplifier; and a ring resonator, having a resonance wavelength, which reflects at least a resonance wavelength in the optical signal, where the reflector and the ring resonator define an optical cavity. Furthermore, the photonic chip includes: a thermal-tuning mechanism that adjusts the resonance wavelength; a photo-detector that measures an optical power output by the ring resonator; and control logic that adjusts the temperature of the ring resonator based on the measured optical power to lock a cavity mode of the optical cavity to a carrier wavelength.

A photonic-crystal surface-emitting laser element includes: a first semiconductor layer formed by embedding a photonic crystal layer that includes air holes arranged with two-dimensional periodicity in a formation region in a plane parallel to the photonic crystal layer; an active layer formed on the first semiconductor layer; a second semiconductor layer formed on the active layer; and a mesa portion with a mesa shape formed at a surface of the second semiconductor layer, wherein the mesa portion is located inside the formation region of the air holes when viewed in a direction perpendicular to the photonic crystal layer.

A semiconductor laser diode includes a semiconductor body having an emitter region; and a first connection element that electrically contacts the semiconductor body in the emitter region, wherein the semiconductor body is in contact with the first connection element in the emitter region, at least in places in the emitter region, the semiconductor body has a structuring that enlarges a contact area between the semiconductor body and the first connection element, the semiconductor body includes a connection region that directly adjoins the first connection element at the contact area, and the connection region is a highly p-doped layer.