Systems and methods described herein are directed to optical light sources, such as an external cavity laser (ECL) with an active phase shifter. The system may include control circuitry for controlling one or more parameters associated with the active phase shifter. The phase shifter may be a p-i-n phase shifter. The control circuitry may cause variation in a refractive index associated with the phase shifter, thereby varying a lasing frequency of the ECL. The ECL may be configured to operate as a light source for a light detection and ranging (LIDAR) system based on generating frequency modulated light signals. In some embodiments, the ECL may generate an output LIDAR signal with alternating segments of increasing and decreasing chirp frequencies. The ECL may exhibit increased stability and improved chirp linearities with less dependence on ambient temperature fluctuations.

Systems and methods described herein are directed to optical light sources, such as an external cavity laser (ECL) with an active phase shifter. The system may include control circuitry for controlling one or more parameters associated with the active phase shifter. The phase shifter may be a p-i-n phase shifter. The control circuitry may cause variation in a refractive index associated with the phase shifter, thereby varying a lasing frequency of the ECL. The ECL may be configured to operate as a light source for a light detection and ranging (LIDAR) system based on generating frequency modulated light signals. In some embodiments, the ECL may generate an output LIDAR signal with alternating segments of increasing and decreasing chirp frequencies. The ECL may exhibit increased stability and improved chirp linearities with less dependence on ambient temperature fluctuations.

A laser device (100), being configured for generating laser pulses by Ken lens based mode locking, comprises a laser resonator (10) with a plurality of resonator mirrors (11.1, 11.2, 11.3) spanning a resonator beam path (12), a solid state gain medium (20) being arranged in the laser resonator (10), a Kerr medium device (30) being arranged with a distance from the gain medium (20) in the laser resonator (10), wherein the Kerr medium device (30) includes at least one Ken medium being arranged in a focal range of the resonator beam path and being configured for forming the laser pulses by the nonlinear Kerr effect, and a loss-modulation device (31, 32) having a modulator medium, which is capable of modulating a power loss of the laser pulses generated in the laser resonator (10), wherein the Kerr medium device (30) includes the modulator medium of the loss-modulation device (31, 32) as the at least one Kerr medium having an optical non-linearity being adapted for both of creating the Kerr lens based mode-locking in the laser resonator and modulating the power loss in the laser resonator. Furthermore, a method of generating laser pulses by Kerr lens based mode locking is described, wherein a loss-modulation device (31, 32) is used for both of introducing a Ken effect in the laser resonator (10) and modulating the power loss.

Apparatus for providing optical radiation (15), which apparatus comprises an optical input (13), a coupler (2), a first semiconductor amplifier (3), a controller (4), a preamplifier (61), a power amplifier (62) and an output fibre (5), wherein: the optical input (13) is for receiving input optical radiation (14); the optical input (13) is connected in series to the coupler (2), the first semiconductor amplifier (3), the preamplifier (61), the power amplifier (62), and the output fibre (5); the apparatus being characterized in that: the first semiconductor amplifier (3) comprises a waveguide (6) having a low reflecting facet (8); the first semiconductor amplifier (3) is in a double pass configuration such that the low reflecting facet (8) is connected to both the optical input (13) and the preamplifier (61) via the coupler (2); and the controller (4) is configured to cause the waveguide (6) of the first semiconductor amplifier (3) to operate in saturation thereby enabling the first semiconductor amplifier (3) to reduce non-linear effects in the preamplifier (61), the power amplifier (62), and the output fibre (5).

Apparatus for providing optical radiation (15), which apparatus comprises an optical input (13), a coupler (2), a first semiconductor amplifier (3), a controller (4), a preamplifier (61), a power amplifier (62) and an output fibre (5), wherein: the optical input (13) is for receiving input optical radiation (14); the optical input (13) is connected in series to the coupler (2), the first semiconductor amplifier (3), the preamplifier (61), the power amplifier (62), and the output fibre (5); the apparatus being characterized in that: the first semiconductor amplifier (3) comprises a waveguide (6) having a low reflecting facet (8); the first semiconductor amplifier (3) is in a double pass configuration such that the low reflecting facet (8) is connected to both the optical input (13) and the preamplifier (61) via the coupler (2); and the controller (4) is configured to cause the waveguide (6) of the first semiconductor amplifier (3) to operate in saturation thereby enabling the first semiconductor amplifier (3) to reduce non-linear effects in the preamplifier (61), the power amplifier (62), and the output fibre (5).

A single-laser light source system for cold atom interferometers, comprising: a reference light module including a narrow-bandwidth laser and a frequency stabilization module and an optical frequency shift module including a first electro-optic modulator and a first narrow-bandwidth optical-fiber filter. The first electro-optic modulator is connected to the first narrow-bandwidth optical-fiber filter by an optical fiber, and the first electro-optic modulator is connected to the laser by an optical fiber. The first electro-optic modulator receives an initial light from the laser, modulates the initial light by a modulation signal with a preset frequency, and generates sidebands with the preset frequency. The first narrow-bandwidth optical-fiber filter filters the optical signal at the output of the first electro-optic modulator to obtain a frequency-shifted light as the +1-order sideband. The frequency-shifted light is used for modulation to obtain a measurement and control light of the cold atom interferometer.

A single-laser light source system for cold atom interferometers, comprising: a reference light module including a narrow-bandwidth laser and a frequency stabilization module and an optical frequency shift module including a first electro-optic modulator and a first narrow-bandwidth optical-fiber filter. The first electro-optic modulator is connected to the first narrow-bandwidth optical-fiber filter by an optical fiber, and the first electro-optic modulator is connected to the laser by an optical fiber. The first electro-optic modulator receives an initial light from the laser, modulates the initial light by a modulation signal with a preset frequency, and generates sidebands with the preset frequency. The first narrow-bandwidth optical-fiber filter filters the optical signal at the output of the first electro-optic modulator to obtain a frequency-shifted light as the +1-order sideband. The frequency-shifted light is used for modulation to obtain a measurement and control light of the cold atom interferometer.

An exposure method includes reading data representing a relationship between a first parameter relating to an energy ratio between energy of first pulsed laser light having a first wavelength and energy of second pulsed laser light having a second wavelength longer than the first wavelength and a second parameter relating to a sidewall angle of a resist film that is the angle of a sidewall produced when the resist film is exposed to the first pulsed laser light and the second pulsed laser light, and determining a target value of the first parameter based on the data and a target value of the second parameter; and exposing the resist film to the first pulsed laser light and the second pulsed laser light by controlling a narrowed-line gas laser apparatus to output the first pulsed laser light and the second pulsed laser light based on the target value of the first parameter.

A control method for a line narrowed gas laser apparatus is a control method for a line narrowed gas laser apparatus configured to emit a pulse laser beam including a first wavelength component and a second wavelength component. The apparatus includes a laser chamber including a pair of electrodes, an optical resonator including an adjustment mechanism configured to adjust a parameter of an energy ratio of the first and second wavelength components, and a processor in which relation data indicating a relation of the parameter of the energy ratio with a control parameter of the adjustment mechanism is stored. The control method includes receiving a command value of the parameter of the energy ratio from an external device, and acquiring, based on the relation data, a value of the control parameter corresponding to the command value and controlling the adjustment mechanism based on the value of the control parameter.

A narrowed-line gas laser apparatus includes a laser chamber that accommodates a pair of electrodes disposed so as to face each other, an output coupling mirror, and a line narrowing apparatus that forms an optical resonator along with the output coupling mirror, the line narrowing apparatus including an optical system having a first region and a second region on which a first portion and a second portion of a light beam that exits out of the laser chamber are incident, the first and second portions passing through different positions in a direction in which the pair of electrodes face each other, the optical system being configured to suppress an increase in the distance between the optical path axis of the first portion and the optical path axis of the second portion.