Systems, devices, and methods for delivering laser energy directed toward target tissue using a spectroscopic feedback. An exemplary laser feedback control system comprises a feedback analyzer to receive a signal from a target tissue using a spectroscopic sensor, and a laser controller to determine whether the received signal generally equals a first preset. If the received signal meets the first preset, the laser controller can send a control signal to a laser system to change from a first state to a second state of the first laser system. The laser system can deliver laser energy via an optical fiber towards the target tissue.

An 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.

The invention provides an excimer laser system including a means for calibrating laser output to compensate for increased variation in laser optical fibers.

A wavelength selection method for a tunable laser includes: obtaining a target wavelength; and calculating target resistance values of two thermistors, respectively, corresponding to the target wavelength. Each of the two thermistors is used to monitor the temperature of a corresponding one of two wavelength selection components. Each of the target resistance values is calculated according to a relationship between a wavelength drift and a resistance change of the corresponding thermistor and according to an initial wavelength and an initial resistance value of the corresponding thermistor corresponding to the initial wavelength. The method further includes: heating the two wavelength selection components to control their temperatures until real-time resistance values of the two thermistors reach the target resistance values, respectively; and stabilizing the real-time resistance values at the target resistance values and outputting a laser beam having the target wavelength.

A laser gas regenerating apparatus regenerates a discharged gas discharged from at least one ArF excimer laser apparatus and supplies the regenerated gas to the at least one ArF excimer laser apparatus connected to a first laser gas supply source that supplies a first laser gas and to a second laser gas supply source that supplies a second laser gas. The laser gas regenerating apparatus includes a data obtaining unit that obtains data on a supply amount of the second laser gas supplied to the at least one ArF excimer laser apparatus; a xenon adding unit that adds, to the regenerated gas, a third laser gas; and a control unit that controls, based on the supply amount, an addition amount of the third laser gas by the xenon adding unit.

A beam quality control device includes an optical fiber, a stress-applying portion, and a temperature controller. The optical fiber has a core and a cladding that surrounds an outer peripheral surface of the core. The stress-applying portion is in surface-contact with at least a portion of an outer peripheral surface of the optical fiber. The stress-applying portion has a coefficient of thermal expansion of the stress-applying portion that is different from a coefficient of thermal expansion of the cladding. The temperature controller controls a temperature of the stress-applying portion. The stress-applying portion contracts or expands due to the temperature being changed by the temperature controller such that a distribution of external force applied by the stress-applying portion to the cladding becomes non-uniform in a peripheral direction of the cladding.

In an example, the disclosed technology includes a laser source, comprising a plurality of pump elements configured to generate laser light, a controller coupled to the plurality of pump elements, configured to select individual drive current levels to be provided to respective ones of the plurality of pump elements responsive to a request for a laser power level and at least one power supply coupled to one or more of the plurality of pump elements for driving individual pump elements at selected drive currents.

A wavelength selection method for a tunable laser includes: obtaining a target wavelength; and calculating target resistance values of two thermistors, respectively, corresponding to the target wavelength. Each of the two thermistors is used to monitor the temperature of a corresponding one of two wavelength selection components. Each of the target resistance values is calculated according to a relationship between a wavelength drift and a resistance change of the corresponding thermistor and according to an initial wavelength and an initial resistance value of the corresponding thermistor corresponding to the initial wavelength. The method further includes: heating the two wavelength selection components to control their temperatures until real-time resistance values of the two thermistors reach the target resistance values, respectively; and stabilizing the real-time resistance values at the target resistance values and outputting a laser beam having the target wavelength.

In a first embodiment, an external cavity tunable laser, comprising a silicon photonics circuit comprising one or more resonators having one or more p-i-n junctions; wherein a voltage is applied to one or more of the p-i-n junctions. In a second embodiment, a method of operating an external cavity tunable laser, comprising sweeping out free-carriers from a resonator of the tunable laser by applying a voltage to a p-i-n junction of a waveguide of the resonator.

Optical line amplifiers with on-board controllers and supervisory devices for controlling optical line amplifiers are provided for controlling bootstrap or power-up procedures when optical line amplifiers are initially installed in an optical communication network. The controllers may include non-transitory computer-readable medium configured to store computer logic having instructions that, when executed, cause one or more processing devices to block an input to one or more gain units of the line amplifier and cause the line amplifier to operate in an Amplified Spontaneous Emission (ASE) mode. In response to a detection of a valid power level of the line amplifier, the instructions can further cause the one or more processing devices to switch the line amplifier from the ASE mode to a regular mode and unblock the input to the one or more gain units of the line amplifier to allow operation of the line amplifier in the regular operating mode.