A semiconductor device. In some embodiments, the semiconductor device includes: a first layer having a first region and a second region, the first region being corrugated with a plurality of corrugations, the second region being uncorrugated. A first cycle of the corrugations may have a first duty cycle and a second cycle of the corrugations may have a second duty cycle, the second cycle being between the first cycle and the second region, and the second duty cycle being between the first duty cycle and the duty cycle of the second region.

A dielectric-grating waveguide free-electron laser device generating coherent or laser-like radiation is provided. An electron beam propagates next to a dielectric waveguide with a built-in grating structure to generate highly confined coherent or laser-like radiation in the waveguide through the Bragg resonance, the backward-wave resonance, or the Fabry-Perot resonance provided by the grating-waveguide structure. The dielectric-grating waveguide can be made of linear optical materials or nonlinear optical materials or combination of linear and nonlinear optical materials to enable versatile functionalities, such as laser generation, laser-wavelength conversion, and laser signal processing. Owing to the build-up of the laser modes inside the dielectric waveguide, coherent or laser-like Smith-Purcell radiation is also generated above the grating via coupling and bunching of the electrons with the surface mode fields.

An optically pumped on-chip solid-state laser includes a solid gain media substrate and a laser generating structure disposed above the solid gain media substrate. The laser generating structure includes a resonator, a pump light input structure, and a laser light output structure; and the resonator is disposed between the pump light input structure and the laser light output structure, and is propped against or is in clearance fit with the solid gain media substrate.

A system and method for tuning and infrared source laser in the Mid-IR wavelength range. The system and method comprising, at least, a plurality of individually tunable emitters, each emitter emitting a beam having a unique wavelength, a grating, a mirror positioned after the grating to receive at least one refracted order of light of at least one beam and to redirect the beam back towards the grating, and a micro-electro-mechanical systems device containing a plurality of adjustable micro-mirrors.

A grating device includes a supporting body having a first main face and a second main face, an under clad layer provided on the first main face of the supporting body, an optical material layer provided on the under clad layer, and a back face layer provided on the second main face of the supporting body. The under clad layer is composed of g a material having a refractive index of 1.69 or lower. The optical material layer is composed of a metal oxide having a refractive index of 1.70 or higher and 3.50 or lower and includes a Bragg grating. The back face layer is composed of a material having a refractive index of 1.69 or lower or a metal oxide having a refractive index of 1.70 or higher and 3.50 or lower.

Examples of the present invention include integrated erbium-doped waveguide lasers designed for silicon photonic systems. In some examples, these lasers include laser cavities defined by distributed Bragg reflectors (DBRs) formed in silicon nitride-based waveguides. These DBRs may include grating features defined by wafer-scale immersion lithography, with an upper layer of erbium-doped aluminum oxide deposited as the final step in the fabrication process. The resulting inverted ridge-waveguide yields high optical intensity overlap with the active medium for both the 980 nm pump (89%) and 1.5 μm laser (87%) wavelengths with a pump-laser intensity overlap of over 93%. The output powers can be 5 mW or higher and show lasing at widely-spaced wavelengths within both the C- and L-bands of the erbium gain spectrum (1536, 1561 and 1596 nm).

The present invention concerns a waveguide amplifier and a waveguide amplifier device comprising it. In addition, the invention concerns a method for producing such waveguide amplifier. The invention especially relates to erbium doped waveguide amplifiers having a controlled doping concentration.

A tunable laser has a first mirror, a second mirror, a gain medium, and a directional coupler. The first mirror and the second mirror form an optical resonator. The gain medium and the directional coupler are, at least partially, in an optical path of the optical resonator. The first mirror and the second mirror comprise binary super gratings. Both the first mirror and the second mirror have high reflectivity. The directional coupler provides an output coupler for the tunable laser.

The invention relates to a surface refractive index scanning system for characterization of a sample. The system comprises a grating device for holding or receiving the sample, the device comprising at least a first grating region having a first grating width along a transverse direction, and a second grating region having a second grating width in the transverse direction. The first grating region and the second grating region are adjacent in the transverse direction, wherein the first grating region has a grating period Λ.sub.1 in a longitudinal direction, and the second grating region has a grating period Λ.sub.2 in the longitudinal direction, where the longitudinal direction is orthogonal to the transverse direction. A grating period spacing ΔΛ=Λ.sub.1-Λ.sub.2 is finite. Further, the first and second grating periods are chosen to provide optical resonances for light respectively in a first wavelength band and a second wavelength band, light is being emitted, transmitted, or reflected in an out-of-plane direction, wherein the first wavelength band and the second wavelength band are at least partially non-overlapping in wavelength. The system further comprises a light source for illuminating at least a part of the grating device with light at an illumination wavelength band. Additionally, the system comprises an imaging system for imaging the emitted, transmitted or reflected light from the grating device. The imaging system comprises an optical element, such as a cylindrical lens or a bended mirror, configured for focusing light in a transverse direction and for being invariant in an orthogonal transverse direction, the optical element being oriented such that the longitudinal direction of the grating device is oriented to coincide with the invariant direction of the optical element, and an imaging spectrometer comprising an entrance slit having a longitudinal direction oriented to coincide with the invariant direction of the optical element. The imaging spectrometer further comprises a 2-dimensional image sensor. The invention further relates to a method.

A distributed feedback laser, including: an output end including an active region including a grating including a λ/4 phase-shift region; and a non-output end including a reflecting region including a grating with uniform period. The length of the active region is smaller than or equal to 200 μm. The end facet of the output end of the laser is coated with an anti-reflection film.