Disclosed are a gain adjustment method and an optical fiber amplifier. The gain adjustment method is applied to an optical fiber amplifier at least including a gain medium, a dynamic gain equalizer and a control unit. The method is performed by the control unit, and includes: determining a property parameter of the gain medium and a current attenuation spectrum of the dynamic gain equalizer; determining, in a preset gain attenuation-spectrum library, a gain attenuation-spectrum mapping table corresponding to the property parameter, wherein the gain attenuation-spectrum mapping table includes a mapping relationship between each gain of the optical fiber amplifier and one attenuation spectrum of the dynamic gain equalizer; obtaining a target gain of the optical fiber amplifier; determining a target attenuation spectrum in the gain attenuation-spectrum mapping table according to the target gain; and adjusting the current attenuation spectrum to the target attenuation spectrum.

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 and the wavelength level adjuster are sequentially connected. The controller includes a first input end and a control output end. The first input end is configured to receive an input optical signal of the fiber amplifier, 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 based on the adjustment control signal.

A laser apparatus includes a semiconductor laser element, a waveform calculation unit for calculating input waveform data, a driver circuit for supplying a drive current having a temporal waveform according to the input waveform data to the semiconductor laser element, an optical amplifier for amplifying laser light output from the semiconductor laser element, and a light waveform detection unit for detecting a waveform of laser light after the amplification output from the optical amplifier. The waveform calculation unit compares the waveform of the laser light after the amplification detected by the light waveform detection unit with a target waveform, adjusts a temporal waveform of the input waveform data, and brings the waveform of the laser light after the amplification close to the target waveform.

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.

An optical amplifier which can suppress, without measuring signal beam power at individual wavelengths, wavelength-dependence of gain with respect to a signal beam into which multiple signal beams having respective wavelengths different from each other are multiplexed. The optical amplifier can suppress wavelength-dependence of gain by giving loss in accordance with a linear-loss slope to an amplified signal beam. The optical amplifier includes a variable tilt equalizer for varying a loss slope value representing the slope of the loss slope and a tilt control unit for controlling a loss slope value of the variable tilt equalizer.

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 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 input cells positioned adjacent to each other that are shaped to cause the beams to expand as they propagates away from the input array to be converted from the low fill factor profile to a high fill factor profile and be tapered 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 beams 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 method for fabricating a beam shaper array assembly, where the beam shaper array assembly changes the shape of a plurality of beams. The method includes providing an optical endcap having a plurality of connector stems, welding a fiber to each of the stems to form an emitter array and positioning a beam shaper array adjacent to the endcap opposite to the stems. The method also includes measuring an angle error and a position error of each fiber, calculating a correction for each fiber for the angle error and the position error and correcting the angle and position of each fiber using the calculated corrections.

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 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.