Systems and methods for optical amplifier failure prediction using Machine Learning (ML), such as for an Erbium-Doped Fiber Amplifier (EDFA), are described. A method include obtaining a plurality of inputs from an optical amplifier associated with an optical network; analyzing the plurality of inputs with a trained machine learning model; obtaining an estimate of a total pump current of the optical amplifier as an output of the trained machine learning model; and comparing the estimate of a total pump current to a measured total pump current of the optical amplifier. The steps can include determining a health of the optical amplifier based on the comparing

A laser apparatus includes: (A) a solid-state laser apparatus that outputs burst seed pulsed light containing a plurality of pulses; (B) an excimer amplifier that amplifies the burst seed pulsed light in a discharge space in a single occurrence of discharge and outputs the amplified light as amplified burst pulsed light; (C) an energy sensor that measures the energy of the amplified burst pulsed light; and (D) a laser controller that corrects the timing at which the solid-state laser apparatus is caused to output the burst seed pulsed light based on the relationship of the difference between the timing at which the solid-state laser apparatus outputs the burst seed pulsed light and the timing at which the discharge occurs in the discharge space with a measured value of the energy.

Described herein are methods for developing and maintaining pulses that are produced from compact resonant cavities using one or more Q-switches and maintaining the output parameters of these pulses created during repetitive pulsed operation. The deterministic control of the evolution of a Q-switched laser pulse is complicated due to dynamic laser cavity feedback effects and unpredictable environmental inputs. Laser pulse shape control in a compact laser cavity (e.g., length/speed of light <˜1 ns) is especially difficult because closed loop control becomes impossible due to causality. Because various issues cause laser output of these compact resonator cavities to drift over time, described herein are further methods for automatically maintaining those output parameters.

A method for providing spectral beam combining (SBC) including generating a plurality seed beams each having a central wavelength and a low fill factor profile, where the wavelength of all of the seed beams is different; amplifying the seed beams; causing the amplified beams to expand as they propagate so as to be converted from the low fill factor profile to a high fill factor profile where the high fill factor profile tapers to a lower value at a perimeter of each beam; causing a wavefront of the converted beams to flatten to provide a plurality of adjacent SBC beams having different wavelengths with minimal overlap and a minimal gap between the beams; collimating the SBC beams; and directing the collimated SBC beams onto an SBC element that spatially diffracts the individual beam wavelengths and directing the beams in the same direction as a combined output beam.

A hybrid coherent beam combining (CBC) and spectral beam combining (SBC) fiber laser amplifier system including a beam shaper array assembly and a beam source that provides a plurality of beams having a low fill factor profile. The assembly includes an input beam shaper array having a plurality of rectilinear input cells positioned adjacent to each other that are 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 a plurality of output cells positioned adjacent to each other that are 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.

A coherently beam combining (CBC) fiber laser amplifier system including beam shaper array assembly and a beam source that provides a plurality of beams having a low fill factor profile. The assembly includes an input beam shaper array having a plurality of input cells positioned adjacent to each other that are 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 and cause the profile to taper to a lower value at a perimeter of each input array cell. The assembly further includes an output beam shaper array having a plurality of output cells positioned adjacent to each other that are 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.

An EDFA may include an input photodiode configured to generate a control signal based on an input signal. The EDFA may include a blind stage configured to generate an amplified signal based on the control signal and the input signal. The EDFA may include a non-blind stage configured to generate an output signal based on the amplified signal within the blind stage, the control signal, and a feedback signal. The EDFA may include a filter configured to generate a filtered signal based on the output signal. The EDFA may include an output photodiode configured to generate the feedback signal based on the filtered signal. The EDFA may include an alarm device. A signal within the non-blind stage may be generated based on the feedback signal and the control signal. The alarm device may be configured to generate an alarm signal when the signal exceeds a threshold value.

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 coherently beam combining (CBC) fiber laser amplifier system including beam shaper array assembly and a beam source that provides a plurality of beams having a low fill factor profile. The assembly includes an input beam shaper array having a plurality of input cells positioned adjacent to each other that are 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 and cause the profile to taper to a lower value at a perimeter of each input array cell. The assembly further includes an output beam shaper array having a plurality of output cells positioned adjacent to each other that are 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.

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.