A frequency modulated, continuous wave (FMCW) laser using a microchip gain medium, an optical coupling element, and a tuning element is described. The laser may be part of a coherent laser ranging system.

Reduction or elimination of negative consequences of reflected stray light from lens surfaces is achieved by propagating a laser beam through an eccentric pupil that excludes the optical axis of the system, which is rotationally symmetric. In such systems, stray light reflections eventually are focused onto the unique optical axis of the system, in either a real or virtual focal region. By using an eccentric pupil, all damage due to focusing of the stray light lies outside of the beam. These focal regions can, e.g., be physically blocked to eliminate beam paths that lead to optical damage, re-pulse beams and parasitic lasing.

To provide a mode-locked pulse photoproduction filter for easily realizing self-starting mode-locking, and a laser device for generating a picosecond or femtosecond-pulse laser light by including such filter, the laser device including an amplifying unit for amplifying and outputting a light inside a resonator, and the mode-locked pulse photoproduction filter having a first filter part for selectively outputting a first wavelength component that is a wavelength component of an oscillation band inside the resonator, and a second filter part for selectively outputting a second wavelength component that is a wavelength component different from the oscillation band inside the resonator.

A fixed input current is provided to a pump laser of an optical pumping block. Further, a first tuning temperature is provided to the pump laser while providing the fixed input current. The first tuning temperature is based on a target band of a pumping beam and causes the pump laser to generate a light beam having a first frequency band that is dictated by the first tuning temperature and the fixed input current. Further, a second tuning temperature is provided to a temperature dependent optical reflector configured to receive the light beam. The second tuning temperature is based on the target band of the pumping beam and causes the optical reflector to reflect light of the light beam that is within a second frequency band that corresponds to the target frequency band. The reflected light beam is emitted into a transmission optical medium configured to carry an optical signal.

A steerable laser transmitter and active situational awareness sensor that achieves SWaP-C, steering rate and spectral diversity improvements by scanning a beam with a Micro-Electro-Mechanical System (MEMS) Micro-Minor Array (MMA). One or more sections of non-linear material (NLM) positioned in the optical path (e.g. as annular sections around a conic mirror or as reflective optical coatings on the MMA) are used to convert the wavelength of the beam to a different wavelength while preserving the steering of the beam. The MEMS MMA may include piston actuation of the mirrors to shape the spot-beam.

The present invention benefits from the determination that pre-selected spectral bandwidths that avoid the spectrum of an electronic transition of a metal/alloy vapor allow for welds substantially free from detritus that may discolor the weld. Accordingly, the present invention provides analytical methods, welding methods and fiber lasers configured to provide high quality metal/alloy welds.

The invention discloses a Raman laser apparatus including a linear cavity having a first direction and a second direction opposite to the first direction, the linear cavity including along the first direction: a first optical component, a gain medium, a Raman medium, a lithium triborate (LBO) crystal and a second optical component. The first optical component receives an incident pumping light in the first direction. The gain medium receives the pumping light from the first optical component, and generates a first infrared base laser having a first wavelength. The Raman medium receives the first infrared base laser, and generates a second infrared base laser having a second wavelength. The LBO crystal receives the first and the second infrared base lasers, and generates a visible laser light having a third wavelength. The second optical component is configured to allow the visible laser light to be transmitted out along the first direction.

An optical fiber includes a core and a cladding. An effective area A.sub.eff of light of a fundamental mode, having a wavelength of 1070 nm and propagating through the core, is 500 μm.sup.2 or more. A numerical aperture NA of the core satisfies the following formula:

NA≥(1.3×10.sup.−11×a.sup.4/b.sup.6).sup.1/6

where a (m) is a radius of the core and b (m) is a radius of the cladding. A V value, that is a waveguide parameter of the optical fiber, satisfies the following formula:

V≤1.3583×b.sup.−0.2555.

A method and a laser for breaking through the limitation of fluorescence spectrum on laser wavelength is disclosed. The method includes: exciting electrons to a high energy level by pump light, and suppressing an oscillation of radiation light by laser cavity coating, using a laser resonance to enhance a transition probability of an electron-phonon coupling from the high energy level to a multi-phonon coupling level, so as to realize the emission and enhancement of breakthrough fluorescence spectrum and realize the radiation light oscillation, wherein the laser cavity includes an incident mirror, a folding mirror, a tuning element and an exit mirror arranged in sequence along an optical path direction, the laser gain medium is located between an incident mirror and a folding mirror in the laser resonator, and the tuning element is arranged in the laser cavity at a Brewster angle.

An objective of the present invention is to provide an amplification fiber having a cladding excitation configuration that improves amplification efficiency and an optical amplifier. An amplification fiber (10) according to the present invention is a multi-core amplification fiber having, from one end (E1) to the other end (EE), a plurality of cores (11b) in a cladding (11a), and a total distance from the one end (E1) to the other end (EE) in which rare earth ions are doped differs depending on the types of cores (11b). The cores (11b) are preferably disposed such that the cores of the same type are not adjacent to each other. By arranging the types of the cores in this manner, requirements for inter-core crosstalk can be mitigated since the bands of signal light in the adjacent cores are different. As a result, a density of cladding excitation light can be increased by shortening the inter-core distance, and thus the amplification efficiency can be improved.