Provided is a semiconductor laser element including: a resonator structure; and a first reflection film and a second reflection film provided on a non-emission end surface of the resonator structure and an emission end surface of the resonator structure, respectively. Reflectance R of the second reflection film at a gain wavelength satisfies the following relational expression: R1≤R≤R(Oc)×C where R1 is reflectance of the second reflection film when the resonator structure performs laser oscillation with power 1.4 times a minimum value of threshold power which is minimum power for the resonator structure to perform the laser oscillation, R(Oc) is reflectance of the external resonance mirror, and C is a ratio of light, which is reflected by the external resonance mirror and is incident in the resonator structure, to light which is reflected by the external resonance mirror.

A semiconductor optical device includes an SOI substrate having a waveguide of silicon, and at least one gain region of a group III-V compound semiconductor having an optical gain bonded to the SOI substrate. The waveguide has a bent portion and multiple linear portions extending linearly and connected to each other through the bent portion. The gain region is disposed on each of the multiple linear portions.

In a WBC system of the present disclosure, an LD bar array constituted by a plurality of LD bars is configured such that a main axis direction of an off-angle of at least one LD bar is reversed with respect to a main axis direction of an off-angle of the other LD bar. By doing so, even in the LD bar in which a wavelength distribution in a wafer exists, a difference between a designed lock wavelength and a gain peak wavelength can be kept within a range where an LD oscillation due to an external resonance is possible for all emitters in the LD bar, thereby an output in the WBC system can be maximized.

A light source module includes a first semiconductor laser element hermetically sealed, a second semiconductor laser element hermetically sealed, and firth to fourth optical elements. A first laser beam prior to reaching the first optical element has divergence angle θfd1 in a direction along a second optical axis and divergence angle θsd1 in a direction along a third optical axis, and satisfy 90°>θfd1>θsd1>0°. Divergence angle θfd12 of a first laser beam in the direction along the second optical axis decreases from divergence angle θfd1, the first laser beam having exited the first optical element. A component of a first laser beam in the direction along the second optical axis is collimated, the first laser beam having exited the second optical element. The same applies to the second semiconductor laser element.

Implementing systems and methods for operating a LiDAR system. The methods comprise: supplying current from a laser diode bar driver of the LiDAR system to a light source of the LiDAR system; passing the current through a laser diode bar of the light source (the laser diode bar comprising a plurality of laser diodes electrically connected in series); emitting a light beam from the light source when current is passing through the plurality of laser diodes; and/or receiving light reflected off an object.

In various embodiments, laser systems or resonators incorporate two separate cooling loops that may be operated at different cooling temperatures. One cooling loop, which may be operated at a lower temperature, cools beam emitters. The other cooling loop, which may be operated at a higher temperature, cools other mechanical and/or optical components, for example optical elements such as lenses and/or reflectors.

A spectroscopic laser sensor based on hybrid III-V/IV system-on-a-chip technology. The laser sensor is configured to either (i) be used with a fiber-optic probe connected to an intravenous/intra-arterial optical catheter for direct invasive blood analyte concentration level measurement or (ii) be used to measure blood analyte concentration level non-invasively through an optical interface attached, e.g., to the skin or fingernail bed of a human. The sensor includes a III-V gain-chip, e.g., an AIGalnAsSb/GaSb based gain-chip, and a photonic integrated circuit, with laser wavelength filtering, laser wavelength tuning, laser wavelength monitoring, laser signal monitoring and signal output sections realized on a chip by combining IV-based semiconductor substrates and flip-chip AIGal-nAsSb/GaSb based photodetectors and embedded electronics for signal processing. Embodiments of the invention may be applied for real-time monitoring of critical blood analyte concentration levels such as lactates, urea, glucose, ammonia, albumin, etc.

It is an aim of the present invention to provide ultra-compact highly-integrated diffraction-grating semiconductor lasers on chips. Various embodiments combined enable the lasers to be compact in size, light weight, mechanically rugged, low in manufacturing cost, and in some cases high in electrical wall-plugged power efficiency or high in optical power output, comparing to typical lasers based on discrete optical components.

Various technologies described herein pertain to injection locking on-chip laser(s) and external on-chip resonator(s). A system includes a first integrated circuit chip and a second integrated circuit chip. The first integrated circuit chip and the second integrated circuit chip are separate integrated circuit chips and can be optically coupled to each other. The first integrated circuit chip includes a laser configured to emit light via a first path and a second path. The second integrated circuit chip includes a resonator formed of an electrooptic material. The resonator can receive the light emitted by the laser of the first integrated circuit chip via the first path and return feedback light to the laser of the first integrated circuit chip via the first path. The feedback light can cause injection locking of the laser to the resonator to control the light emitted by the laser (e.g., via the first and second paths).

A laser module includes: a laser diode bar including a plurality of emitters configured to emit laser light from a front surface and leak light from a rear surface; a housing including a reflecting surface configured to surround a space together with the laser diode bar and reflect, toward the space, light leaked from the rear surface, in a scattering manner; and a detector configured to detect light reflected by the reflecting surface. A laser module includes: a laser diode bar including a plurality of emitters configured to emit laser light from a front surface and leak light from a rear surface; a condenser lens on which light leaked from rear surfaces of all of the plurality of emitters impinges; and a detector configured to detect light transmitted through the condenser lens.