Fluctuations in optical output are positively suppressed in a laser apparatus that adjusts the temperature of a housing that contains constituent components of a laser to be a predetermined temperature. Constituent components of a laser that include a resonator constituted by the back end surface of a laser diode and a resonator mirror are contained within a housing. The housing is bonded to a Peltier element via an adhesive layer. The Peltier element is driven based on detected temperatures within the housing to adjust the housing to be of a predetermined temperature. An adhesive layer in which a plurality of substantially uniformly shaped spacers that regulate the distance between the housing and the Peltier element are dispersed is employed as the adhesive layer.

An optical system can lock a wavelength of a tunable laser to a specified wavelength of a temperature-insensitive spectral profile of a spectral filter. In some examples, the spectral filter, such as a Fabry-Perot filter, can have a temperature-insensitive peak wavelength and increasing attenuation at wavelengths away from the peak wavelength. The spectral filter can spectrally filter the laser light to form filtered laser light. A detector can detect at least a fraction of the filtered laser light. Circuitry coupled to the detector and the laser can tune the tunable laser to set a signal from the detector to a specified value corresponding to a specified wavelength in the spectral profile, and thereby adjust the selectable wavelength of the tunable laser to match the specified wavelength. In some examples, the optical system can include a polarization rotator, and can use polarization to separate incident light from return light.

A light source device includes a semiconductor laser that has a first end surface and a second end surface parallel to each other and forming a first resonator, and an optical system that is disposed on an optical path of laser light emitted from the semiconductor laser, that forms a second resonator with the second end surface of the semiconductor laser, and that has a reflection characteristic in which a reflectance with respect to light having a previously specified wavelength width centered at a specified center wavelength of the semiconductor laser is higher than the reflectance of the first end surface.

The invention relates to a resonator mirror (4) for an optical resonator (1) of a laser device (2), especially of a gas laser or a slab waveguide laser, comprising a reflective surface (6) with a structured area (5) which spans across a region of the reflective surface (6) centered about the optical axis (5). According to one variant of the principle underlying the invention, the structured area (5) has at least one reflective surface cross-section (8, 18, 28, 38, 48, 58, 68) which is offset with respect to the reflective surface (6) outside the structured area (5) and parallel to the optical axis (A) by half of a predefined wavelength or by a whole multiple of half the predefined wavelength. According to another variant, the structured area (5) has at least two surface cross-sections (8, 18, 28, 38, 48, 58, 68) which are offset against each other and parallel to the optical axis (A) by half of a predefined wavelength or by a whole multiple of half the predefined wavelength. In addition, the invention relates to a laser device (2) whose optical resonator (1) comprises a resonator mirror (4) designed in such a manner.

An optical element may include a plurality of subsurface induced scattering centers formed in the optical element, where the plurality of subsurface induced scattering centers scatter light passing through the optical element. In some implementations, the plurality of subsurface induced scattering centers may form a scattering region in the optical element. Additionally, or alternatively, the plurality of subsurface induced scattering centers may spatially vary transmission of light through the optical element. The optical element may be an optical waveguide, a bulk optic, and/or the like.

System and method for utilizing a serial array (10) of large laser cores (11), positioned inside an external cavity formed with full reflection mirrors (12) and a partial reflection mirror (13), containing a mode-selection mechanism, based on a seeding laser (14), a Fabry-Perot (16), and an isolator (15), for ensuring only the axial wave (17) can exist, generating correspondingly an output beam (18) of high power as well high beam quality.

A method of inducing light losses at a parasitic wavelength in a fiber laser system includes providing a wavelength discriminator (WD) spaced from and between feeding and process fibers or from the end output of the feeding fiber so as to induce losses of light at parasitic wavelength. The device implementing the disclosed method is configured with a laser source, the delivery fiber and WD spaced at a distance between the surface to be treated and the end of the delivery fiber, wherein the WD receives the parasitic light over free space and is configured as a dichroic filter inducing losses to the light at the parasitic wavelength.

A laser light source includes: a resonance unit with a light emitter; and an optical negative feedback unit. The resonance unit includes: a first waveguide; a first reflector to input the reflected light to the first waveguide; a second waveguide; a second reflector connected to the second waveguide; and a ring resonator between the first waveguide and the second waveguide. The light from the first reflector is blocked from the ring resonator and partially transmitted to a first end of the first waveguide opposite to a second end connected to the light emitter and the first reflector. The optical negative feedback unit includes: a third waveguide to which the light transmitted to the first end of the first waveguide is inputted; and a third reflector connected to the third waveguide. The light from the third reflector is inputted to the first waveguide via the third waveguide.

A laser apparatus, a measurement apparatus, and a measurement method are provided in which the laser apparatus outputs a frequency-modulated laser beam with a plurality of modes and includes: an optical cavity that has a gain medium for amplifying a light to be input, and an optical SSB modulator for shifting a frequency of the light amplified by the gain medium: and a control part that controls the optical SSB modulator to shift a frequency of a light to be input to the optical SSB modulator.

A laser system, comprising: a laser cavity, a gain medium positioned within the laser cavity, a pump source optically coupled to the gain medium, an input minor positioned at a first end of the laser cavity, an output coupler positioned at a second end of the laser cavity, a first etalon positioned within the laser cavity, and a q-switching element positioned within the laser cavity, wherein the laser system is configured to provide a laser beam at a selected wavelength ranging of 1700 to 3000 nm with a tunable spectral range of at least 10 nm. A method for using the laser system e.g., for producing a pulsed laser beam is further disclosed.