A pulsed fiber generator is configured with a unidirectional ring waveguide configured to emit a train of pulses. The ring waveguide includes multiple fiber amplifiers, chirping fiber components coupled to respective outputs of first and second fiber amplifiers, and multiple spectral filters coupled to respective outputs of the chirping components. The filters have respective spectral band passes centered around different central wavelengths so as to provide leakage of light along the ring cavity in response to nonlinear processes induced in the ring cavity. The pulse generator operates at a preliminary stage during which it is configured to develop a pitch to a signal, and at a steady stage during which it is configured to output a train of pulses through an output coupler at most once per a single round trip of the signal.

A method and apparatus for control of a dose of extreme ultraviolet (EUV) radiation generated by a laser produced plasma (LPP) EUV light source. Each laser pulse is modulated to be of a width that is determined to be sufficient to allow for extraction of a suitable uniform amount of energy in the laser source gain medium; in some embodiments the suitable uniform amount of energy to be extracted may be selected to avoid self-lasing. The EUV energy created by each pulse is measured and total EUV energy created by the fired pulses determined, and a desired energy for the next pulse is determined based upon whether the total EUV energy is greater or less than a desired average EUV energy times the number of pulses. The energy of the next pulse is modulated, either by modulating its magnitude or by modulating the amplification of the pulse by one or more amplifiers, but without decreasing the determined width of the laser pulse.

A semiconductor laser device includes: a semiconductor laser element including an emitter that emits emission light; a lens that transmits the emission light emitted from the emitter; a driver that supports the lens in a state in which a position and an orientation of the lens are changeable; a detector that detects an intensity distribution of the emission light emitted from the emitter and transmitted through the lens; and a controller that, based on a detection result of the detector, controls at least one of the position or the orientation of the lens by driving the driver to cause the intensity distribution of the emission light detected by the detector to be a predetermined light intensity distribution.

A technique related to a semiconductor chip is provided. An optical gain chip is attached to a semiconductor substrate. An integrated photonic circuit is on the semiconductor substrate, and the optical gain chip is optically coupled to the integrated photonic circuit thereby forming a laser cavity. The integrated photonic circuit includes an active intra-cavity thermo-optic optical phase tuner element, an intra-cavity optical band-pass filter, and an output coupler band-reflect optical grating filter with passive phase compensation. The active intra-cavity thermo-optic optical phase tuner element, the intra-cavity optical band-pass filter, and the output coupler band-reflect optical grating filter with passive phase compensation are optically coupled together.

A technique related to a semiconductor chip is provided. An optical gain chip is attached to a semiconductor substrate. An integrated photonic circuit is on the semiconductor substrate, and the optical gain chip is optically coupled to the integrated photonic circuit thereby forming a laser cavity. The integrated photonic circuit includes an active intra-cavity thermo-optic optical phase tuner element, an intra-cavity optical band-pass filter, and an output coupler band-reflect optical grating filter with passive phase compensation. The active intra-cavity thermo-optic optical phase tuner element, the intra-cavity optical band-pass filter, and the output coupler band-reflect optical grating filter with passive phase compensation are optically coupled together.

An intra-cavity doubled OPS-laser has a laser-resonator including a birefringent filter (BRF) for coarse wavelength-selection, and an optically nonlinear (ONL) crystal arranged for type-II frequency-doubling and fine wavelength-selection. Laser-radiation circulates in the laser-resonator at one of a range of fundamental wavelengths dependent on the resonator length. The ONL crystal has a transmission peak-wavelength dependent on the crystal temperature. Reflection of circulating radiation from the BRF is monitored. The reflection is at a minimum when the ONL crystal transmission-peak wavelength is at the circulating radiation wavelength. The temperature of the ONL crystal is selectively varied to maintain the monitored reflection at about a minimum.

The present invention provides a burst-laser generator using an optical resonator which produces high pulse-strength of burst-laser in order to conduct laser Compton scattering, comprising: a self-oscillation amplifying optical loop-path and an external optical resonator to burst-amplify laser, wherein, laser supplied by an exciting laser source is self-oscillation amplified with the self-oscillation amplifying optical loop-path and further burst-amplified with the external optical resonator.

A swept light source of the present invention keeps a coherence length of an output beam long over an entire sweep wavelength range. A gain of a gain medium is changed with time in response to a wavelength sweep and the coherence length is kept maximum. The gain of the gain medium is kept close to a lasing threshold and an unsaturated gain range of the gain medium is narrowed over the entire sweep wavelength range. An SOA current waveform data acquiring method of driving while keeping the coherence length long, a novel coherence length measuring method, and an optical deflector suitable for the swept light source are also disclosed.

A swept light source of the present invention keeps a coherence length of an output beam long over an entire sweep wavelength range. A gain of a gain medium is changed with time in response to a wavelength sweep and the coherence length is kept maximum. The gain of the gain medium is kept close to a lasing threshold and an unsaturated gain range of the gain medium is narrowed over the entire sweep wavelength range. An SOA current waveform data acquiring method of driving while keeping the coherence length long, a novel coherence length measuring method, and an optical deflector suitable for the swept light source are also disclosed.

A method and a system for controlling an output of an optical system, the method comprising generating a plurality of optical signal components having different optical properties and passing the generated optical signal components as input to an optical system comprising an optical device and/or an optical medium; an output of the optical system being based on interactions of the signal components within the optical device and/or the optical medium; and relative proportions of the optical signal components that are generated and individual optical properties thereof being selected to control the output of the optical system.