The present invention provides an optical amplifier and a control method therefor, with which it is possible to stably control an optical amplifier that uses a multicore optical fiber. The optical amplifier uses, in a gain medium, a multicore optical fiber having a plurality of cores, and comprises: an input-light power monitor that monitors the optical power of input light to the plurality of cores of the multicore optical fiber; an output-light power monitor that monitors the optical power of medium-passed output light from the plurality of cores that has passed through the multicore optical fiber; a crosstalk monitor that monitors the amount of inter-core crosstalk among the plurality of cores; and a controller that controls the pump-light power of pump light superimposed on the input light to the plurality of cores on the basis of the monitored optical power of input light, the monitored optical power of output light, and the monitored amount of inter-core crosstalk.

A laser control device includes a processor configured to control, when a control circuit of a laser device detects occurrence of an abnormality in a laser oscillator or a laser optical system and stops laser output from the laser oscillator, the control circuit based on a result of determining whether to enable or disable re-outputting of laser light from the laser oscillator by inputting, to a classifier, input data being at least a part of environmental data and state data about the laser device in a predetermined period including a stop time of laser output. Then, the state data and the input data in the predetermined period include at least one of time-series data about a light amount of laser light and time-series data about a light amount of return light propagating in a direction opposite to a direction of the laser light in the predetermined period.

A laser protection system includes a high-power laser source, an optical diffuser, a photo detector, a signal-processing device, and a control module. The high-power laser source generates a first laser light beam, and the optical diffuser attenuates a laser power of the first laser light beam to form a second laser light beam. The photo detector obtains an optical detection signal from the second laser light beam. The signal-processing device includes a signal conversion module, a processor, and an encoder. The signal conversion module transforms the optical detection signal into a measurement data eigenvalue. The encoder encodes the measurement data eigenvalue into a measured encoded data, and the setting data eigenvalue into a set encoded data. The control module evaluates the set encoded data and the measured encoded data to determine whether or not the high-power laser source needs to be stopped.

An excimer laser apparatus according to the present disclosure includes a chamber configured to accommodate a laser gas and a pair of electrodes and generate pulse-oscillating laser light when the gas pressure of the laser gas is controlled in accordance with voltage applied between the pair of electrodes, a power supply configured to apply the voltage between the pair of electrodes, and a controller to which a target value of the spectral linewidth of the laser light is inputted, the controller configured to correct the voltage used to control the gas pressure, when the target value changes from a first target value to a second target value, based on a first function having the second target value as a parameter and control the gas pressure in accordance with the corrected voltage.

A laser system's laser light energy control and resulting dose control is improved by creating and using a set of gain estimators, one for each of a set or range of laser light pulse repetition rates. When a new repetition rate is used, its corresponding gain estimator is retrieved, used to compute the voltage to fire the laser source, and updated. The resulting generated laser light thereby avoids the convergence delay inherent in prior laser systems and, further, can repeatedly do so with subsequent specified repetition rates.

A laser system's laser light energy control and resulting dose control is improved by creating and using a set of gain estimators, one for each of a set or range of laser light pulse repetition rates. When a new repetition rate is used, its corresponding gain estimator is retrieved, used to compute the voltage to fire the laser source, and updated. The resulting generated laser light thereby avoids the convergence delay inherent in prior laser systems and, further, can repeatedly do so with subsequent specified repetition rates.

A photodetection device including: first optical fibers; a second optical fiber; an optical combiner having: an end face connected to an end face of each of the first optical fibers; and another end face connected to an end face of the second optical fiber; a first photodetector that detects an intensity of light propagating through at least one of the first optical fibers; a second photodetector that detects Rayleigh scattering of light propagating through the second optical fiber; and a calculator that calculates the intensity of light propagating in a predetermined direction through the first optical fibers or the second optical fiber, from a result of detection by the first photodetector and a result of detection by the second photodetector.

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.

A power-measuring protection method includes the steps of: applying an optical diffuser to attenuate a first laser light beam to form a second laser light beam; applying a photo detector to detect the second laser light beam to obtain an optical detection signal; applying a signal conversion module to transform the optical detection signal into a measurement data eigenvalue; applying a processor to receive the measurement and setting data eigenvalues, and to further transmit these data eigenvalues to an encoder; applying the encoder to encode the measurement data eigenvalue and the setting data eigenvalue, and then to transmit a corresponding measured encoded data and a corresponding set encoded data, respectively, to a control module; and, applying the control module to evaluate the set and measured encoded data to determine whether or not the high-power laser source needs to be stopped. In addition, a laser processing system is also provided.

An all solid-state laser light source device comprises a diode-pump laser and the following devices sequentially arranged in an optical path direction of laser light: a coupling optical fiber, a coupling lens assembly, and a resonant cavity. An anisotropic laser crystal is provided in the resonant cavity. Absorption spectra of the anisotropic laser crystal comprise a π polarization absorption spectrum and a σ polarization absorption spectrum. Each of the π polarization absorption spectrum and the σ polarization absorption spectrum has a peak pump region and a left pump region and a right pump region arranged on either side of the peak pump region. Pump light outputted by diode-pump laser has a wavelength λ falling within the left pump region or the right pump region.