A vertical cavity surface emitting device includes a substrate, a first multilayer film reflecting mirror formed on the substrate, a light-emitting structure layer formed on the first multilayer film reflecting mirror and including a light-emitting layer, and a second multilayer film reflecting mirror formed on the light-emitting structure layer. A resonator is constituted between the second multilayer film reflecting mirror and the first multilayer film reflecting mirror. The light-emitting structure layer includes a low resistance region and a high resistance region. The low resistance region is disposed in a ring shape between the first multilayer film reflecting mirror and the second multilayer film reflecting mirror. The high resistance region is formed inside the low resistance region and has an electrical resistance higher than an electrical resistance of the low resistance region.

A photonics frequency comb generator includes two integrated dies: an indium phosphide die laser of a first wavelength is grown on from, and a silicon photonics die having a microring resonator connected to the laser and frequency modulators. The microring resonator converts the first wavelength into a number of second wavelengths. One type of the microring resonator is a hybrid non-linear optical wavelength generator, comprising non-silicon materials, such as SiC or SiGe built on silicon to yield a non-linear wavelength generation. The second wavelengths are generated by adjusting the ring's geometric size and a distance between the ring and the traverse waveguide. Another type of microring resonator splits the first wavelength into a plurality of second wavelengths and transmits the multiple second wavelengths to filters and modulators, and each selects and modulates one of the second wavelengths in a one-to-one relationship. This frequency comb generator has applications in WDM/CWDM and multi-chip modules in high speed transceivers.

A method for fabricating an array of emitters may include providing a first metallization layer for a first set of emitters of a first channel, wherein the first metallization layer comprises a first interchannel portion positioned between the first set of emitters and a second set of emitters of a second channel. The method may include depositing a dielectric layer on the first interchannel portion of the first metallization layer. The method may include providing a second metallization layer for the second set of emitters, wherein the second metallization layer comprises a second interchannel portion positioned between the first set of emitters and the second set of emitters, and wherein the second interchannel portion of the second metallization layer at least partially overlaps the first interchannel portion of the first metallization layer.

A semiconductor laser element a first ring resonator. The first ring resonator includes a first semiconductor stack including a first n-side semiconductor layer, a first p-side semiconductor layer, and a first active layer located between the first n-side semiconductor layer and the first A-side semiconductor layer, wherein the first ring resonator comprises a diffraction grating. The semiconductor laser element further includes a second ring resonator optically coupled to the first ring resonator by evanescent field coupling. The second ring resonator includes a second semiconductor stack including a second n-side semiconductor layer, a second p-side semiconductor layer, and a second active layer located between the second n-side semiconductor layer and the second p-side semiconductor layer, wherein a peak wavelength of light emitted by the second ring resonator is the same as a peak wavelength of light emitted by the first ring resonator.

In at least one embodiment, the environment sensor for sensing at least one environment parameter includes a semiconductor layer sequence, a sheath, the index of refraction of which changes as a function of the environment parameter, and a first electrical contact and a second electrical contact for supplying current to the semiconductor layer sequence. The semiconductor layer sequence has the shape of a generalized cylinder having a main axis. In directions perpendicular to the main axis, the semiconductor layer sequence is at least partly covered by the sheath. The semiconductor layer sequence has an index of refraction which is greater than the index of refraction of the sheath. The semiconductor layer sequence is designed to form laser modes within the environment sensor. Furthermore, the environment sensor is designed such that, in its normal operation, a change in the index of refraction of the sheath causes a change in the electrical resistance of the semiconductor layer sequence as a result of a change in radiation losses within the semiconductor layer sequence.

In some implementations, a surface emitting laser may have an emitter design with a short oxidation length and/or a large number of trenches. For example, the surface emitting laser may comprise a metallization layer comprising multiple extended portions extending outwards from a circumference of an inner ring portion, and multiple tabs extending laterally from the multiple extended portions in a partial ring shape. The surface emitting laser may further comprise multiple via openings connecting the metallization layer to a plating metal, where each via opening is positioned over a corresponding tab, of the multiple tabs. The surface emitting laser may comprise multiple oxidation trenches that are each formed in an angular gap between a pair of extended portions, of the multiple extended portions, such that the multiple tabs and the multiple via openings are exclusively outside outer radii of the multiple oxidation trenches.

A fully integrated photonic coherent microwave generator includes an external laser cavity on a suitable material waveguide platform (e.g., LiNbO3) operationally integrated with a III-V gain element. Operational components include a tunable high-Q resonator (e.g., LiNbO3 microresonator) and one or more end mirrors to form an integrated semiconductor external-cavity laser. Operationally coupled electrical components enable coherent microwave and phase-locked laser comb outputs as follows. An optical detector converts the beating of generated laser-comb modes into microwaves with a fundamental frequency equal to the free-spectral range f.sub.R of the microresonator. The external laser cavity enables high-speed electro-optic modulation of laser modes directly inside the laser cavity. Phase locking of the lasing modes is accomplished via electro-optic modulation and electro-optic comb generation directly inside the laser cavity. Highly coherent microwaves are generated via phase-locked comb-like lasing modes.

To realize a reservoir computing system with a small size and reduced learning cost, provided is a laser apparatus including a laser; a feedback waveguide that is operable to feed light output from the laser back to the laser; an optical splitter that is provided in a path of the feedback waveguide and is operable to output a portion of light propagated in the feedback waveguide to outside; and a first ring resonator that is operable to be optically connected to the feedback waveguide, as well as a reservoir computing system including this laser apparatus.

Example embodiments relate to lasers that include loop resonators. One example laser includes a loop resonator forming a closed loop light path. The loop resonator includes an optical gain medium configured to lase. The loop resonator is configured to, during lasing, present a pair of modes: a mode of light propagating in a clockwise direction in the closed loop light path of the loop resonator (termed CW mode) and a mode of light propagating in a counter-clockwise direction in the closed loop light path of the loop resonator (termed CCW mode). The laser also includes a first light output configured to output laser light from the laser. Additionally, the laser includes an optical power modulating unit. The optical power modulation unit is configured to modulate an optical power of the CW mode of the loop resonator and an optical power of the CCW mode of the loop resonator.

A tuneable ring laser having a ring cavity, wherein the ring cavity comprises at least one ring resonator having a waveguide for guiding waves, a phase modulator having a waveguide for guiding waves, one or more power couplers for coupling the waves in, and out of, the at least one ring resonator, wherein a cross section of the waveguides of the at least one ring resonator and the phase modulator is configured as PIN diodes and act as an electro-refractive modulator such that the tuneable ring laser is tuneable by applying a reverse bias voltage.