An all-fiber laser oscillator comprises a laser cavity, an amplification fiber, a plurality of diode lasers, and at least one side-pump signal-and-pump combiner (combiner). The combiner comprises a double-clad fiber (DCF) and four or more multimode fibers (MMFs). DCF comprises a first taper portion, whereas each of MMFs comprises a second taper portion fused around DCF. MMFs are configured to carry a portion of combined optical energy (COE) and to couple to DCF. The first taper portion can partially compensate a beam divergence created by the second taper portion, thereby increasing a coupling efficiency of COE coupled from MMFs to DCF with improved thermal performance. In a coupling portion, a refractive index difference between MMFs and DCF is configured to form a backward coupling barrier to suppress an optical energy in DCF from coupling into MMFs, thereby protecting the plurality of diode lasers from damage.

A device for the generation of ultrashort pulses, wherein an oscillator is formed by: a first and a second non-overlapping transmission band-pass filter, which can serve as reflecting end element of the oscillator; optically transparent means with non-linear Kerr coefficient χ.sup.(3) different from zero configured to achieve a spectral broadening by self-phase modulation of the signal transiting through these means; an optical waveguide that produces a positive gain; a node configured to receive a trigger signal designed to activate the operation of the oscillator; a trigger signal generating device comprising: a laser source, for example a microchip, configured to generate a laser pulse, preferably with a minimum bandwidth, having a duration of hundreds of ps, up to the ns; a coupling system designed to introduce the pulse of the trigger laser into a waveguide made of an optically transparent material characterised by a non-linear Kerr coefficient χ.sup.(3) different from zero, which is configured to produce two distinct effects in order to spectrally broaden the pulse of the trigger laser, and precisely: a) self-phase modulation four-wave mixing; the output of the waveguide supplies the trigger signal to the node. The pulses produced by the oscillator typically have a duration of the order of the picosecond and are easily reduced to the Fourier limit of circa 100 femtoseconds by means of a dispersive device.

A mode-lockable ring oscillator includes a gain element for amplifying an optical pulse into an amplified pulse, a nonlinear optical element for broadening the amplified pulse into a first spectrally-broadened pulse, a first optical filter for filtering the first spectrally-broadened pulse into a first filtered pulse, a passive nonlinear optical element for broadening the first filtered pulse into a second spectrally-broadened pulse, and a second optical filter for filtering the second spectrally-broadened pulse into a second filtered pulse. The first and second optical filters have passbands that partially overlap such that the ring cavity can lase CW. With these spectrally overlapping passbands, the mode-lockable ring oscillator can directly initiate single-pulse mode-locking by modulating pump power that pumps the gain element. After this modulation has stopped, the mode-lockable ring oscillator maintains this single-pulse mode-locking while the passbands remain spectrally overlapped.

In some implementations, a device may apply a modulation to an electrical current to derive a modulated electrical current. The device may supply the modulated electrical current to an optical pump source for an optical amplifier to cause the optical pump source to emit light based on the modulated electrical current. The device may generate a signal based on an optical power of the light emitted by the optical pump source. The device may filter the signal with respect to a feedback signal that is to result from the modulated electrical current to derive a filtered signal. The device may process the filtered signal to identify whether the feedback signal is present in the filtered signal based on a power indicated by the filtered signal. Whether the feedback signal is present indicates a state of the optical pump source.

Provided are a laser device and an optical apparatus including the same. The laser device includes a pump light source configured to provide pump light, a gain medium configured to acquire a gain of seed laser light by using the pump light, a first curved mirror and a second curved mirror, which are provided at both sides of the gain medium to reflect the seed laser light into the gain medium, an output mirror configured to transmit a portion of the seed laser light reflected by the second curved mirror and reflect the other portion of the seed laser light to the gain medium, a first acoustic wave generator connected to the gain medium and configured to provide a first photoacoustic wave in the gain medium, and a second acoustic wave generator connected to the gain medium and configured to provide a second photoacoustic wave in the gain medium.

A broadband source device configured for generating broadband radiation or white light output. The broadband source device includes a gas cell, and a hollow-core photonic crystal fiber at least partially enclosed within the gas cell. A gas mixture is within the gas cell and the hollow-core photonic crystal fiber. The gas mixture includes at least one Raman active molecular gas constituting more than 2% of the gas mixture, such that the broadband source device operates in a balanced Kerr-Raman nonlinear interaction regime.

A method for providing spectral beam combining (SBC) including generating a plurality seed beams each having a central wavelength and a low fill factor profile, where the wavelength of all of the seed beams is different; amplifying the seed beams; causing the amplified beams to expand as they propagate so as to be converted from the low fill factor profile to a high fill factor profile where the high fill factor profile tapers to a lower value at a perimeter of each beam; causing a wavefront of the converted beams to flatten to provide a plurality of adjacent SBC beams having different wavelengths with minimal overlap and a minimal gap between the beams; collimating the SBC beams; and directing the collimated SBC beams onto an SBC element that spatially diffracts the individual beam wavelengths and directing the beams in the same direction as a combined output beam.

A Raman fiber laser includes a pump light source, a reflective end mirror, a wavelength division multiplexer, a Raman gain fiber, and an output end mirror. The output end mirror is an ultra-low reflectance fiber Bragg grating. The reflective end mirror is connected to a reflective end of the wavelength division multiplexer. The pump light source is connected to an input end of the wavelength division multiplexer. One end of the Raman gain fiber is connected to a common end of the wavelength division multiplexer, and the other end of the Raman gain fiber is connected to the ultra-low reflectance fiber Bragg grating. The laser of the present invention can reduce loss of laser light at the reflective end mirror, thereby increasing laser light optical conversion efficiency and output power, and simultaneously achieving high time domain stability and extremely low coherence.

In various embodiments, one or more optical elements are utilized to alter the numerical aperture of a radiation beam received from an optical fiber in order to accommodate the properties of a downstream collimator within a laser delivery head.

A laser device may include a laser resonator; a chamber arranged on an optical path of the laser resonator; a pair of electrodes arranged in the chamber; a power source applying a voltage to the electrodes; a storage unit storing a voltage value; and a control unit configured to set an application voltage value of the voltage applied to the electrodes as setting the application voltage value for outputting a pulse whose pulse number is equal to or larger than 1 and smaller than i based on the voltage command value and the voltage value stored in the storage unit, and setting the application voltage for outputting a pulse whose pulse number is equal to or larger than i and smaller than j based on the voltage command value and an offset value corresponding to the voltage command value, where i>1 and j>i.