A laser oscillator includes a first structure disposed with an optical section, a second structure disposed with a power source section, and an electric cable that electrically connects the optical section and the power source section. The first structure is removably coupled to the second structure, the electric cable is removably connected to at least one of the power source section and the optical section, and the optical section is allowed to be replaced.

In some implementations, a thermally-controlled photonic structure may include a suspended region that is suspended over a substrate; a plurality of bridge elements connected to the suspended region and configured to suspend the suspended region over the substrate, where a plurality of openings are defined between the plurality of bridge elements; and at least one heater element having a modulated width disposed on the suspended region. The at least one heater element having the modulated width may include at least one section of a greater width and at least one section of a lesser width. The at least one section of the greater width may be in alignment with an opening of the plurality of openings and the at least one section of the lesser width may be in alignment with a bridge element of the plurality of bridge elements.

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.

Provided is a fixing device for a diffraction element including an element installation portion where a diffraction element is installed, and an element fixing portion that fixes the diffraction element installed on the element installation portion, wherein the element installation portion includes an element installation surface for curving the installed diffraction element in a discretionary shape, and the element installation surface is formed in an arch-like shape such that deformation of the diffraction element due to pressure of a cooling fluid is reduced.

Described herein are isolated ring cavities that have refractive and heat-generating components physically separated and mechanically held by flexure mounts that are adapted to function in combination with the physically separated structure to moderate the thermal expansion effects of the heat generated by the refractive and other heat-generating elements (e.g., gain element) of the optical cavity. The flexure mounts may be configured as thinned portions of connective elements, reducing the effects of thermal expansion of the baseplate and allowing a thermal isolation from the baseplate. Multiple flexure mounts may be arranged to minimize further the effects of thermal expansion of the baseplate.

In various embodiments, laser devices feature means, such as fasteners, for attaching a laser package to a cooling plate, which allow motion of the laser package in response to thermal cycles resulting from operation of a beam emitter therewithin. Embodiments of the invention additionally or instead include laser devices featuring segmented barrier layers for electrically isolating the laser package from the cooling plate.

Provided is a laser device in which: a laser medium doped with ytterbium emits light upon absorption of excitation light; the light emitted by the laser medium is amplified to obtain output light; and the output light is outputted in the form of a plurality of pulses. In the laser device, a spatial filter is disposed in the optical path of the light emitted by the laser medium or is disposed in the optical path of the output light outputted from an optical resonator, the spatial filter being configured to filter out a portion of the light or of the output light around the optical axis.

An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The optical semiconductor device is applied to a ridge-stripe type laser.

A single-frequency laser apparatus comprises a mirror and a volume Bragg grating (VBG) reflector defining a laser cavity therebetween and an optical gain material for emitting and amplifying an intra-cavity beam in the laser cavity. The optical gain material comprises a transition-metal doped crystal such as a crystal doped with transition-metal ions selected from one or more of Ti.sup.3+ ions, Cr.sup.2+ ions, Cr.sup.3+ ions or Cr.sup.4+ ions. A reflectivity spectrum of the VBG reflector and an optical length of the laser cavity are selected so that a beam output from the laser cavity is a single-frequency output beam and/or includes only one longitudinal mode of the laser cavity. The laser apparatus may provide a robust, compact, low cost, high-power wavelength adjustable (from approximately 650 to 950 nm), narrow linewidth (<100 kHz), single frequency laser source which is suitable for a wide range of applications from laser sensing, spectroscopy, and high precision frequency metrology sectors.

A laser resonator assembly and a method of assembly of the laser resonator assembly are described. The laser resonator assembly has a gain element and an output coupler that are placed in a gain element frame and output coupler frame, respectively. The output coupler may also be a saturable absorber element so that the laser resonator assembly emits Q-switched pulses. The frames provide heat dissipation and can be easily aligned and permanently affixed in an appropriate alignment. A laser using the laser resonator assembly can be assembled in a low-cost manner.