An optical amplifier includes two amplifier stages, a circulator and an output stage. The first amplifier stage amplifies an input optical signal, and provides a first-stage amplified optical signal that is to be outputted via the circulator to the second amplifier stage. The second amplifier stage amplifies the first-stage amplified optical signal, and outputs a second-stage amplified optical signal to the output stage. The output stage outputs a returned optical signal to the second amplifier stage, so that the second amplifier stage amplifies the returned optical signal, and provides a third-stage amplified optical signal that is to be outputted via the circulator and the output stage to serve as an output optical signal.

An amplified spontaneous emission (ASE) light source and a method for using the ASE light source are provided. The ASE light source may include a seed stage light source for providing a light beam to be amplified. The apparatus may include a tunable element coupled to the seed stage light source configured for filtering a portion of the light beam from the seed stage light source. The apparatus may include a loopback circuit coupled to the tunable element, the loopback circuit comprising a booster stage element for amplifying light from the tunable element.

A beam shaper array assembly including a beam source that provides a plurality of beams having a low fill factor profile. The assembly also includes an input beam shaper array having cells positioned adjacent to each other, where each cell includes an input beam shaper that receives one of the plurality beams and is shaped to cause the beam to expand as it propagates away from the input array to be converted from the low fill factor profile to a high fill factor profile. The assembly further includes an output beam shaper array having cells positioned adjacent to each other, where each cell includes an output beam shaper that receives one of the converted beams and is shaped to cause the beam to stop expanding so that the output array provides a plurality of adjacent beams with minimal overlap and a minimal gap between the beams.

At least one beam of pump pulses is combined in a nonlinear process with a plurality of monochromatic beams, each containing signal pulses of a unique wavelength. This produces an ensemble of beams of pulses having wavelengths of medium length. Then, all of the pulses in all of the beams in the ensemble are subject to second harmonic generation, optical parametric amplification, sum-frequency generation, or combinations to reduce the wavelengths of those pulses to ultraviolet wavelengths, thereby creating driver pulses. Driver beams made up of those reduced-wavelength driver pulses can then be focused upon a fuel pellet.

A laser transmitter including a waveform controller arranged to generate a waveform script having at least one of a pulse repetition frequency setting, a pulse duration setting, and a pulse amplitude pre-warp setting. The transmitter also includes an optical waveform generator arranged to: i) receive the waveform script, ii) generate pre-warped signal pulses based on the waveform script to compensate for gain distortion effects of a laser power amplifier, and iii) output the pre-warped signal pulses. The laser power amplifier is arranged to: i) receive the pre-warped signal pulses, ii) receive a continuous wave signal, and iii) output amplified signal pulses that maintain a substantially constant drive intensity at the input of a non-linear wavelength converter. The non-linear wavelength converter is arranged to receive the amplified signal pulses and emit wavelength-converted pulses.

The present invention discloses a transverse mode switchable all-fiber high-order mode Brillouin laser. The laser comprises a narrow linewidth pump laser, an optical amplifier, a 1×N optical switch (N≥2), a fiber mode selection coupler group, a first polarization controller, a fiber circulator, a fiber coupler, a second polarization controller, and a few-mode fiber. Based on the Brillouin nonlinear gain of a few-mode fiber in a ring cavity, the present invention realizes the resonance amplification of a specific order transverse mode in the cavity, and obtains the transverse mode switchable high-order mode laser beam output. The present invention, adopting an all-fiber structure, has the advantages of simple structure, low cost, easy fiber system integration, high stability and narrow linewidth of outputted laser beams, etc., and improves the practicality and reliability of high-order mode lasers.

The de-multiplexing unit 2 de-multiplexes an inputted optical wavelength multiplexed signal into a first optical wavelength multiplexed signal having a first wavelength band and a second optical wavelength multiplexed signal having a second wavelength band in a longer wavelength band than the first wavelength band. The first optical amplifier 3 amplifies the first optical wavelength multiplexed signal. The second optical amplifier 4 amplifies the second optical wavelength multiplexed signal. The multiplexer 5 multiplexes the amplified first optical wavelength multiplexed signal and the amplified second optical wavelength multiplexed signal and outputs the multiplexed signal to a Raman amplifier 6. The first optical amplifier 3 adjusts the amplification rate of the first optical wavelength multiplexed signal so that the intensity of light in the second wavelength band is compensated for by the Raman effect in the Raman amplifier 6.

A rod-type photonic crystal fiber amplifier includes a signal coupling lens, a first dichroic mirror, a first hollow pump coupling lens, and a rod-type photonic crystal fiber. The rod-type photonic crystal fiber comprises a core and a cladding, wherein signal light is coupled into the core of the rod-type photonic crystal fiber through the signal coupling lens, and pump light is coupled into the cladding of the rod fiber through the hollow pump coupling lens. The structure optimizes the coupling between the signal light and the core of the rod-type photonic crystal fiber, and the coupling between the pump light and the cladding of the rod fiber respectively by introducing the hollow pump coupling lens. The purpose of this is to fully optimize the rod-type photonic crystal fiber amplifier, improve the amplification efficiency and improve the efficiency of a manufacturing process.

In a laser system according to a viewpoint of the present disclosure, a first amplifier amplifies first pulsed laser light outputted from a first semiconductor laser system into second pulsed laser light, a wavelength conversion system converts the second pulsed laser light in terms of wavelength into third pulsed laser light, and an excimer amplifier amplifies the third pulsed laser light. The first semiconductor laser system includes a first current controller that controls current flowing through a first semiconductor laser in such a way that first laser light outputted from the first semiconductor laser is caused to undergo chirping and a first semiconductor optical amplifier that amplifies the first laser light into pulsed light. The laser system includes a control section that controls the amount of chirping performed on the first pulsed laser light in such a way that excimer laser light having a target spectral linewidth is achieved.

This optical amplification module includes a light source that outputs light of a predetermined wavelength as excitation light, a first optical coupler that splits the excitation light into first excitation light and second excitation light such that an optical power ratio becomes a predetermined ratio, and then couples the first excitation light with a first optical signal and outputs the result, and outputs the second excitation light to a different path from the first optical signal and a first optical amplifier that amplifies and outputs the first optical signal.