Abstract: External cavity laser systems are described that can operate with essentially no mode hopping. One example configuration of the laser system includes a semiconductor laser device, a folded cavity external to the semiconductor laser device, where at the semiconductor laser device is positioned at a fold in the folded cavity. In this configuration, at least one mirror is positioned in the folded cavity to enable sustained propagation of light within the folded cavity, and at least two polarization elements are positioned in the folded external cavity. The polarization elements cause a polarization state of the light that impinges in different directions on each semiconductor laser device that is positioned at a fold to be orthogonal to one another, thus eliminating or substantially reducing mode hopping in the laser output.

Abstract: Methods, devices and systems for improving single-frequency operation of diode lasers are described. One such method includes ramping up an operational current of a diode laser for a first predetermined number of steps, and measuring an associated current value indicative of optical power within the laser diode for each of the first predetermined number of steps. Next, operational current of the diode laser is ramped down for a second predetermined number of steps, and an associated current value indicative of optical power within the laser diode is measured for each of the second predetermined number of steps. Using the measured data current values at which a mode hop or a multimode operation is likely to occur are identified, and a contiguous range of operating currents that is devoid of identified likely mode hops or multimode regions of operation is determined as the operating current range of the diode laser.

Abstract: The described methods and devices minimize or reduce the effects of the leading amplified spontaneous emission component of an optical pulse in optical multi-pass amplifier systems. One multi-pass optical amplifier includes a gain medium positioned to receive a pump laser, and to receive an optical pulse having a main component and one or both of a leading or a trailing component. The optical amplifier also includes one or more reflectors positioned at a first side or at a second side of the gain medium that allow multi-pass propagation of the optical pulse through the gain medium. The one or more reflectors are positioned to allow the main component of the optical pulse to traverse through the gain medium in a first pass before the leading component of the optical pulse reaches the gain medium in a second pass through the gain medium.

Abstract: Methods, systems and methods for reducing temporal coherence of laser systems are described. One example laser system includes a seed laser having a continuous wave output and operable at a first wavelength, a phase modulator positioned to receive laser light from the seed laser and to impart phase modulation to the seed laser. The laser system also includes an optical parametric amplifier positioned to receive phase-modulated laser light at one of its inputs and a pump laser light at another input, and to produce an output beam having spectral characteristics of the phase-modulated laser light that is amplified according to a temporal feature of the pump laser light. In the example laser system, an output of the optical parametric amplifier has a lower temporal coherence compared to the seed laser.

Abstract: Methods, devices and systems for improving single-frequency operation of diode lasers are described. One such method includes ramping up an operational current of a diode laser for a first predetermined number of steps, and measuring an associated current value indicative of optical power within the laser diode for each of the first predetermined number of steps. Next, operational current of the diode laser is ramped down for a second predetermined number of steps, and an associated current value indicative of optical power within the laser diode is measured for each of the second predetermined number of steps. Using the measured data current values at which a mode hop or a multimode operation is likely to occur are identified, and a contiguous range of operating currents that is devoid of identified likely mode hops or multimode regions of operation is determined as the operating current range of the diode laser.

Abstract: External cavity diode laser (ECDL) devices and methods for producing the same are described that allows ECDLs to be readily produced and configured to operate at a desired range of wavelengths, while allowing tunability of the output wavelength. One ECDL includes a laser gain chip including a gain medium, a first reflective surface at a first end of the gain medium, and a second surface at a second end of the gain medium opposite to the first reflective surface. The second surface has a facet that forms an angle approximately equal to Brewster's angle for light having a first wavelength. The ECDL further includes a diffraction grating positioned to receive light that passes through the second surface, to operate as a mirror in the external cavity diode laser, and to allow a portion of the light to be directed outside of the external cavity diode laser as output light.

Abstract: External cavity laser systems are described that can operate with essentially no mode hopping. One example configuration of the laser system includes a semiconductor laser device, a folded cavity external to the semiconductor laser device, where at the semiconductor laser device is positioned at a fold in the folded cavity. In this configuration, at least one mirror is positioned in the folded cavity to enable sustained propagation of light within the folded cavity, and at least two polarization elements are positioned in the folded external cavity. The polarization elements cause a polarization state of the light that impinges in different directions on each semiconductor laser device that is positioned at a fold to be orthogonal to one another, thus eliminating or substantially reducing mode hopping in the laser output.

Abstract: External cavity diode laser (ECDL) devices and methods for producing the same are described that allows ECDLs to be readily produced and configured to operate at a desired range of wavelengths, while allowing tunability of the output wavelength. One ECDL includes a laser gain chip including a gain medium, a first reflective surface at a first end of the gain medium, and a second surface at a second end of the gain medium opposite to the first reflective surface. The second surface has a facet that forms an angle approximately equal to Brewster's angle for light having a first wavelength. The ECDL further includes a diffraction grating positioned to receive light that passes through the second surface, to operate as a mirror in the external cavity diode laser, and to allow a portion of the light to be directed outside of the external cavity diode laser as output light.

Abstract: In one embodiment, the present disclosure provides a deep ultraviolet laser generation device 1000 having a first laser source 100 at a first wavelength between 1.87 ?m and 2.1 ?m, a second laser source 200 at a second wavelength between 1.53 ?m and 1.57 ?m, a nonlinear wavelength conversion element 3 for generating near-infrared light 31 at a wavelength between 841 nm and 899 nm through a sum-frequency mixing (SFM) process, a nonlinear wavelength conversion element 4 for generating blue light 41 at a wavelength between 420 nm and 450 nm from the near-infrared light through a second harmonic generation (SHG) process, and a third nonlinear wavelength conversion element 5 for generating deep ultraviolet light 51 at a wavelength between 210 nm and 225 nm from the blue light, through another SHG process.

Abstract: In one embodiment, the present disclosure provides a deep ultraviolet laser generation device 1000 having a first laser source 100 at a first wavelength between 1.87 ?m and 2.1 ?m, a second laser source 200 at a second wavelength between 1.53 ?m and 1.57 ?m, a nonlinear wavelength conversion element 3 for generating near-infrared light 31 at a wavelength between 841 nm and 899 nm through a sum-frequency mixing (SFM) process, a nonlinear wavelength conversion element 4 for generating blue light 41 at a wavelength between 420 nm and 450 nm from the near-infrared light through a second harmonic generation (SHG) process, and a third nonlinear wavelength conversion element 5 for generating deep ultraviolet light 51 at a wavelength between 210 nm and 225 nm from the blue light, through another SHG process.

Abstract: A time delay is introduced in the optical path of the light pulse at fundamental wavelength relative to that for the fourth harmonic light pulse in a set up for generating the 5th harmonic, to compensate for at least a portion of the time delay of the fourth harmonic relative to the fundamental wavelength caused by 4HG generation. In one embodiment, this is achieved by introducing a time delay of the fundamental relative to the second harmonic wavelength, such as preferably by means of a timing compensator in the optical paths of the second harmonic and the fundamental wavelength. Preferably, any further delay of the fourth harmonic relative to the fundamental wavelength caused by other optical components can also be compensated for in this manner.

Abstract: In order to generate efficiently a deep ultraviolet laser beam having a wavelength in a deep ultraviolet region and to make the generated laser beam to be high output, it is arranged in such that a laser beam having about 227 nm wavelength is generated by sum-frequency mixing of fourth harmonic of the laser beams obtained by amplifying semiconductor laser beams having 1064.0 to 1065.0 nm wavelengths by means of an optical fiber amplifier, and the laser beams obtained by amplifying semiconductor laser beams having 1557.0 to 1571.0 nm wavelengths by means of another optical fiber amplifier; and further laser beams having 198.4 to 198.7 nm wavelengths are generated by sum-frequency mixing of the above sum-frequency mixed laser beam and the above-described semiconductor laser beams having 1557.0 to 1571.0 nm wavelengths.

Abstract: The present invention provides a deep ultraviolet laser apparatus exhibiting high robustness which can generate laser beams in a wavelength region of wavelengths of from 198.3 to 198.8 nm, further may be loaded on a variety of apparatuses as a light source for lighting, and is practicable and a size of the whole structure of thereof is reduced. The deep ultraviolet laser apparatus is arranged in such that laser beams having a wavelength of from 1064 to 1065 nm pulse-output from a first light source is a first fundamental wave; fourth harmonic obtained by wavelength-converting the first fundamental wave by means of a first wave-length conversion means is a second fundamental wave; laser beams having a wavelength of from 1560 to 1570 nm pulse-output from a second light source is a third fundamental wave; second harmonic obtained by wavelength-converting the third fundamental wave by means of a second wave-length conversion means is a fourth fundamental wave; and laser beams having a wavelength of from 198.

Abstract: An all-fiber Q-switched laser includes a gain fiber spliced between narrowband and broadband fiber gratings that define a polarization-dependent resonant cavity. The narrowband grating is, for example, formed in a PM fiber to create a polarization-dependent reflection band. A modulator applies stress to the fiber chain to induce birefringence and switch the cavity Q-factor to alternately store energy in the gain fiber and then release the energy in a laser pulse.

Abstract: A compact single frequency, single-mode 1 ?m fiber laser with narrow linewidth (<10 kHz) and high output power (>2 mW) is formed with an oxide-based multi-component glass fiber doped with triply ionized rare-earth ytterbium ions and fiber gratings formed in sections of passive silica fiber and fused thereto. The multi-component glass supports higher doping concentrations than standard silica fiber, hence higher output power levels in short cavities. Formation of the gratings in passive silica fiber both facilitates splicing to other optical components and reduces noise thus improving linewidth.

Abstract: A short laser cavity (up to 30 cm in length) comprising a free-space tunable MEMS Fabry-Perot filter, a collimating lens and a section of erbium-doped phosphate gain fiber (2-25 cm) is formed between a pair of broadband reflectors. The cavity is optically pumped to excite the erbium ions and provide gain, which establishes an initial longitudinal mode structure that spans the C-band with a mode spacing of at least 0.3 GHz and a roundtrip unsaturated gain of at least 8 dB over the tuning range. A controller tunes the MEMS filter, which has a filter function whose spectral width is at most ten and preferably less than four times the longitudinal mode spacing, to align its transmission maxima to one of a plurality of discrete output wavelengths that span the C-band. A thermal control element adjusts the longitudinal mode structure to align a single mode with the transmission maxima of the filter.

Abstract: A short laser cavity (up to 30 cm in length) comprising a free-space tunable MEMS Fabry-Perot filter, a collimating lens and a section of erbium-doped phosphate gain fiber (2-25 cm) is formed between a pair of broadband reflectors. The cavity is optically pumped to excite the erbium ions and provide gain, which establishes an initial longitudinal mode structure that spans the C-band with a mode spacing of at least 0.3 GHz and a roundtrip unsaturated gain of at least 8 dB over the tuning range. A controller tunes the MEMS filter, which has a filter function whose spectral width is at most ten and preferably less than four times the longitudinal mode spacing, to align its transmission maxima to one of a plurality of discrete output wavelengths that span the C-band. A thermal control element adjusts the longitudinal mode structure to align a single mode with the transmission maxima of the filter.

Abstract: A multi-port optical amplifier chip has an inner cladding layer sandwiched between a pair of outer cladding layers, a plurality of active core elements disposed substantially within the inner cladding layer to receive optical signals at respective input ports and transmit amplified optical signals at respective output ports, a pair of reflecting surfaces on opposing sides of the inner cladding and at least one pump source. The pump source directs pump light into the inner cladding layer where it is confined to bounce back-and-forth across the active core elements thereby enhancing the absorption of pump light into the core elements, hence increasing gain. Greater than 5 dB over the C-band (1930 nm-1965 nm) in less than 10 cm is expected with a phosphate glass material co-doped with greater than 2 weight percent Erbium and 10 weight percent Ytterbium. A number of fiber drawing based approaches are contemplated for manufacturing the amplifiers to achieve this performance and reduce cost.

Abstract: A compact, high-power, low-cost broadband ASE source is achieved by multi-mode pumping a highly doped multi-component glass fiber in standard ASE source configurations. The multi-mode pump is coupled into and propagates in the fiber cladding exciting the rare-earth dopant ions (Er,Yb) in the fiber core. The multi-component glass includes a network former selected from either phosphate (P2O5) or tellurite (TeO2) and is doped with at least 0.25 weight percent rare-earth dopants. The high concentrations of dopants supported by these glasses absorbs the multi-mode pump in a short length, less than 100 cm, and provides high saturated output powers.

Abstract: A compact, low-cost mid-gain Erbium Micro-Fiber Amplifier (EMFA) is provided by multi-mode pumping a micro fiber formed from a specialty multi-component glass and highly co-doped with Er:Yb. The specialty glass exhibits a much higher core absorption coefficient than standard glasses. As a result, the lower order modes are rapidly absorbed in the fiber core. The abrupt change in the mode profile perturbs the higher order modes and mode couples them into the lower order modes within a very short length of fiber, less than 20 cm. This “absorptive mode coupling” effect can double the absorption efficiency of a circular symmetric micro fiber and extend the length over which such a highly doped fiber can be efficiently inverted. The combination of multi-mode pumping with short fiber lengths reduces the form factor and cost of EMFAs.