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 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.

Among other embodiments, a method for generated entangled photons is disclosed. The method comprises generating photons in a fundamental mode and converting the photons from the fundamental mode to a higher-order mode. The method further comprises generating, by a Bragg resonator configured to receive the photons, entangled photons in the fundamental mode from the converted photons in the higher-order mode. The method further comprises outputting the generated entangled photons from the Bragg resonator.

A laser light source includes an inner ring and an outer ring. The inner ring includes a semiconductor optical amplifier (SOA), a pair of optical circulators, a first optical filter, and a first optical waveguide connecting those in series. The outer ring includes the SOA, a pair of optical circulators, a second optical filter, an output port, and a second optical waveguide connecting those in series except for a portion shared. The inner ring operates as a gain-clamped SOA with a feedback control light defined by the first optical filter. The outer ring generates a laser output in a gain region of the clamped SOA, and with multiple peak wavelengths defined by the second optical filter, in a range from L Band to U band, applicable to WDM network systems. A WDM network system and a method of controlling the laser light source are also disclosed.

A semiconductor laser device includes: a support base having a plurality of mounting surfaces arranged in a first direction, wherein heights of the mounting surfaces from a reference plane that is parallel to the first direction decrease stepwise or gradually along the first direction; a first semiconductor laser element secured to a first mounting surface; a second semiconductor laser element secured to a second mounting surface; a first slow-axis collimator lens secured to the first mounting surface, the first slow-axis collimator lens being located at a position at which the first laser light is incident; a second slow-axis collimator lens directly or indirectly secured to the second mounting surface, the second slow-axis collimator lens being located at a position at which the second laser light is incident; and a first sealing cover that defines an inner space in which the first and second semiconductor laser elements are held.

Some embodiments may include a fiber laser system comprising: a pump combiner; a plurality of fiber laser pump modules arranged for pumping a pulsed output from the fiber laser system; and a pump controller to operate in a first operation mode to pump a pulsed output from the fiber laser system and to operate in a second different operation mode to pump a continuous wave (CW) output from the fiber laser system; the pump controller to, in the first operation mode, simultaneously activate individual fiber laser pump modules of the plurality of fiber laser pump modules; and the pump controller to, in the second operation mode, sequentially activate the individual fiber laser pump modules of the plurality of fiber laser pump modules. Other embodiments may be disclosed and/or claimed.

A solid-state laser system includes a gain medium having an optical resonator defined therein. The gain medium is co-doped with first and second active elements. The first active element is Er.sup.3+ and the second active element is Ho.sup.3+ or Dy.sup.3+. The solid-state laser system also includes a pump source coupled to the gain medium for pumping the gain medium with pump light.

A semiconductor-fiber-laser assembly is provided that includes a pumping module, an active optical fiber and an assembling board. The active optical fiber is provided on an upper surface of the assembling board, the pumping module is provided on a surface of the assembling board that is the same as or opposite to the upper surface; and input-side and output-side optical-fiber gratings are provided at two ends of the active optical fiber, to form a laser resonator between the input-side and output-side optical-fiber gratings. The pumping module includes a plurality of semiconductor-laser single emitters, a collimating-lens group and a mirror group that are sequentially arranged, and light beams from the semiconductor-laser single emitters pass through the mirror group to realize beam combination.

Incoherently combining light from different lasers while maintaining high brightness is challenging using conventional fiber bundling techniques, where fibers from different lasers are bundled adjacently in a tight-packed arrangement. The brightness can be increased by tapering the tips of the bundled fibers to match a single, multi-mode output fiber, e.g., one whose core that is just wide enough to fit the input cores. This increases the brightness of the beam combining. In addition, reducing the outer diameters of the signal fiber claddings allows the signal fibers to be bundled closer together, making it possible to couple more signal fiber cores to the core of a multi-mode output fiber. Similarly, reducing the outer diameter of the pump fiber cladding and/or etching away corresponding portions of the signal fiber cladding in a pump/signal combiner makes it possible to couple more pump light into the signal fiber cladding, again increasing brightness.

A system, device, and method for laser cooling rare earth doped silica glass using anti-Stokes fluorescence is disclosed. The system includes a rare earth doped and codoped with one or more codopants silica glass; a laser that provides radiation to a first surface and through a body of the rare earth doped silica glass, wherein the laser is tuned from a first wavelength to a second wavelength; and a thermally sensitive device that captures images of the rare earth doped silica glass as the laser is tuned and determines a third wavelength between the first wavelength and the second wavelength where the rare earth doped silica glass is maximumly or near maximumly cooled.