An example laser apparatus of the disclosure may include an oscillator capable of outputting a laser beam, a slab optical amplifier capable of amplifying the laser beam outputted by the oscillator by passing the laser beam through an optical amplification region shaped like a slab and outputting the amplified laser beam, and a mirror disposed on an optical path of the laser beam to enter the slab optical amplifier or the amplified laser beam outputted from the slab optical amplifier, the mirror being movable in a direction parallel to a plane where the laser beam travels in the slab optical amplifier.

A method (10) of changing operating mode of an optical amplifier in an amplifier chain in an optical network, the optical amplifier initially configured to operate in a first mode to apply a substantially constant first gain to an optical signal comprising a plurality of optical channels, the method comprising, after a time period unique to the optical amplifier within the amplifier chain (12), configuring the optical amplifier to operate in a second mode to apply a second gain to the optical signal so that the optical power of the optical signal is maintained at a target optical power dependent on a current plurality of optical channels in the optical signal (14).

An example of the disclosure is a laser apparatus including a master oscillator capable of outputting a pulse laser beam, a plurality of optical amplifiers disposed on an optical path of the pulse laser beam outputted from the master oscillator and configured to sequentially amplify the pulse laser beam, an optical reflector capable of passing the pulse laser beam therethrough and reflecting a self-oscillation beam generated in one of the plurality of optical amplifiers, and an optical absorber capable of receiving and absorbing the self-oscillation beam reflected by the optical reflector.

Low wavelength infrared Super Continuum (SC) signals from a master oscillator seeds an amplifier that supports the Raman effect. Counter-propagating, high-power, continuous wave, and quasi-continuous wave quantum cascade lasers pumps (amplify) the optical seeds forming multiple coherent wavelength optical pump sources.

An active laser medium for emitting a light beam by laser effect includes an X—F2-doped crystal, wherein X is a chemical element from the alkaline-earth family and F is fluorine. The crystal is doped with trivalent ions including: a first category of optically active dopant ions, in which each dopant ion is an ion of a first rare earth; and a second category of optically inactive dopant ions, referred to as buffer ions, in which each dopant ion is an ion of a rare earth different from the first rare earth. The second category of dopant ions has at least ions of a second rare earth and ions of a third rare earth, different from one another. The invention provides an active laser medium that can be used to obtain both a desired emission spectrum shape and a high thermal conductivity.

Disclosed is a laser radar device, which includes a signal light source that outputs a first signal light, a pump light source that outputs a pump light, a pump optical fiber that transfers the pump light, a first signal optical fiber that transfers the first signal light, a first amplifier that receives and amplifies the first signal light from the first signal optical fiber, a second signal optical fiber that receives and transfers a second signal light from the first amplifier, the second signal light being obtained by amplifying the first signal light, a second amplifier that receives and amplifies the second signal light from the second signal optical fiber, and an optical coupler connected to the first signal optical fiber, the second signal optical fiber, and the pump optical fiber, and that distributes the pump light to the first signal optical fiber and the second signal optical fiber.

A laser amplifier head is provided. The laser amplifier head includes a plurality of plates of a solid-state laser active medium disposed in a housing, arranged parallel to one another with their main surfaces facing one another, the housing being provided with an inlet port and an outlet port for a cooling liquid, and also at least one window allowing a laser beam to pass through the laser active medium plates, wherein it also includes: a mechanical connection device allowing a cyclic movement at least of the laser active medium plates in relation to the laser beam in a plane (xy) perpendicular to the direction (z) of their thickness; and cooling liquid guide plates arranged in the extension of the laser active medium plates, between the latter and the inlet port of said liquid.

An optical amplification device includes a first Raman amplifier outputs a first excitation light to a transmission line in a same direction as a signal light, and a second Raman amplifier outputs a second excitation light to the transmission line in an opposite direction to the signal light. The first Raman amplifier includes a first detector detects a first power of a first transmitted light transmitted through a first optical filter. The second Raman amplifier includes a second detector detects second power of a second transmitted light transmitted through a second optical filter. The first Raman amplifier stops output of the first excitation light when the first power is higher than a threshold. The second Raman amplifier stops output of the second excitation light when the second power is reduced from power of the first excitation light transmitted through the second optical filter.

Example fiber amplifiers and gain adjustment methods for the fiber amplifiers are described. One example fiber amplifier includes a first power amplifier, a wavelength level adjuster, and a controller, where the first power amplifier is connected to the wavelength level adjuster. The controller includes a first input end and a control output end. The first input end is configured to receive an input optical signal, and the control output end is configured to output a first amplification control signal to the first power amplifier, and output an adjustment control signal to the wavelength level adjuster. The wavelength level adjuster is configured to perform power adjustment on each wavelength in a separate manner based on the adjustment control signal.

A laser processing method of performing laser processing on a transparent material that is transparent to ultraviolet light by using a laser processing system includes: performing relative positioning of a transfer position of a transfer image and the transparent material in an optical axis direction of a pulse laser beam so that the transfer position is set at a position inside the transparent material at a predetermined depth ΔZsf from a surface of the transparent material in the optical axis direction; and irradiating the transparent material with the pulse laser beam having a pulse width of 1 ns to 100 ns inclusive and a beam diameter of 10 μm to 150 μm inclusive at the transfer position.