An external optical feedback element (108) for tuning an output beam of a gas laser (102) having multiple wavelengths includes a partially reflective optical element (108) positioned on a beam path of the output beam (106) outside of an internal optical cavity of the gas laser (102), and a stage (114) to support the optical element and adjust rotation, horizontal tilt angle, and vertical tilt angle of the optical element with respect to the beam path. The output beam (106) is partially reflected at the optical element (108) and fed back into the internal optical cavity of the gas laser (102), with the intensity varying for multiple wavelengths and adjusted by changing rotation, horizontal tilt angle and vertical tilt angle of the optical element. Thereby, a variable feedback of the output beam into the internal optical cavity of the gas laser is provided, which leads to a selective output wavelength of the gas laser, either at a single line or at multiple lines simultaneously. This setup may allow to control the wavelength of a commercial CO2 gas laser without a modification of the laser itself by adding a coupled cavity with a wavelength selective element like a grating to the given gas laser resonator.

A ring cavity laser source, a tunable ring cavity laser source and a method of fabricating a ring cavity laser source. The fiber ring cavity laser source comprises a fiber pigtailed pump laser; a fiber-based gain medium; a fiber-based circulator; a fiber-based coupler, wherein an input fiber port of the fiber-based coupler is coupled to a first end of the fiber-based gain medium, a first output fiber port of the fiber-based coupler is coupled to a first fiber port of the fiber-based circulator, and a second output fiber port of the fiber-based coupler is configured for extracting a laser output of the fiber ring cavity laser source; a fiber-based reflector coupled to a second fiber port of the fiber-based circulator; and a fiber-based combiner, wherein a first input fiber port of the fiber-based combiner is coupled to the fiber pigtailed pump laser, a second input fiber port of the fiber-based combiner is coupled to a third fiber port of the fiber-based circulator, and an output fiber port of the fiber-based combiner is coupled to a second end of the fiber-based gain medium; wherein the fiber-based reflector is configured for wavelength tuning of the laser output.

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 tunable narrow-linewidth photo-generated microwave source based on polarization control includes a high-reflectivity fiber grating, a high-gain fiber, a low-reflectivity polarization-maintaining fiber grating, a stress adjusting device, a single-mode semiconductor pump laser, an optical wavelength division multiplexer, a polarization beam splitter, a polarization controller, an optical coupler, and a photoelectric detector. Birefringence distribution in the low-reflectivity polarization-maintaining fiber grating is controlled by adjusting a stress magnitude of the stress adjusting device to the low-reflectivity polarization fiber grating, thereby controlling a laser frequency working in different polarization modes in a resonant cavity, and a tunable narrow-linewidth photo-generated microwave source is generated by a beat-frequency technology using a dual-wavelength narrow-linewidth laser with variable frequency intervals.

A frequency stabilizing system for high precision single-cavity multi-frequency comb includes a single-cavity multi-comb pulse oscillator, a frequency detection system, and a frequency feedback control system. The single-cavity multi-comb pulse oscillator is configured to output mode-locked pulse trains with a certain repetition rate difference at two or more central wavelengths. The frequency detection system is configured to detect the frequency signal, and output the corresponding electrical signal. The frequency feedback control system is configured to process the electrical signal from the frequency detection system, and transmit it to the frequency response component in the single-cavity multi-comb pulse oscillator to control a strain of the frequency response component, so as to realize feedback control on the frequency (repetition rate, repetition rate difference, and carrier envelope offset frequency) of the mode-locked pulse trains.

Disclosed is an optical kit for forming an optical system including an external resonator of a laser light source that outputs laser light, the optical kit including: a base including a main surface; a light source holding part provided on the main surface for holding the laser light source; and a holding part provided on the main surface for holding the optical system, wherein the holding part has a reflector holding part for holding the corner reflector, a first opening member holding part for holding the first opening member, and a second opening member holding part for holding the second opening member, and wherein the first opening member holding part is positioned closer to the reflector holding part than an emission surface of the laser light of the laser light source held by the light source holding part.

A laser apparatus includes a grating system; an actuator system configured to adjust a first incident angle on the grating system and a second incident angle on the grating system, the first incident angle being an angle of a first part of an optical beam incident on the grating system, the second incident angle being an angle of a second part of the optical beam incident on the grating system; and a processor configured to control the actuator system to periodically vary the first and second incident angles so that the first and second incident angles are different from each other in at least one of phase and variation range.

A laser apparatus includes a grating system; an actuator system configured to adjust a first incident angle on the grating system and a second incident angle on the grating system, the first incident angle being an angle of a first part of an optical beam incident on the grating system, the second incident angle being an angle of a second part of the optical beam incident on the grating system; and a processor configured to control the actuator system to periodically vary the first and second incident angles so that the first and second incident angles are different from each other in at least one of phase and variation range.

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.

The laser module includes a QCL element, a MEMS diffraction grating, a lens holder holding a lens disposed between the QCL element and the MEMS diffraction grating, a package, an electrode terminal disposed along an inner wall surface of the package, and a wire for electrically connecting the electrode terminal and a coil. The top wall of the package faces the bottom wall of the package in a direction orthogonal to the optical axis direction of the lens. The MEMS diffraction grating includes an electrode pad electrically connected to the coil. The electrode pad is connected to the electrode terminal via the wire. A height position of the electrode pad with respect to the bottom wall is equal to or higher than a height position of the electrode terminal with respect to the bottom wall.