Abstract: A pulse laser apparatus includes a laser configured to generate a pulse of a laser beam, a fiber amplifier, and a pulse compressor. The fiber amplifier includes a rare-earth doped fiber that exhibits normal dispersion at a wavelength of the laser beam generated from the laser. The pulse laser apparatus further includes a unit configured to give a loss to energy portions in a wavelength region corresponding to a zero-dispersion wavelength of the rare-earth doped fiber and/or a wavelength region longer than the zero-dispersion wavelength within a wavelength spectrum of the laser beam having been chirped in the fiber amplifier.

Abstract: A nano-wire optical block device for amplifying, modulating, and detecting an optical signal in a large-core hollow metallized waveguide. The nano-wire optical block device comprises a substrate with a plurality of nano-wires coupled to the substrate to form the nano-wire optical block. Each properly formed nano-wire is comprised of a p-doped region, an intrinsic region, and an n-doped region. The nano-wire optical block is operable to be inserted into the large-core hollow metallized waveguide to provide at least one of amplifying, modulating, and detecting the optical signal.

Abstract: The light-enhancing system of the invention comprises a laser diode in which a fully reflecting mirror and/or a partially reflecting mirror of the laser diode is made in the form of digital planar holography (DPH) incorporating a mode-reorganization function that decreases divergence and improves brightness of the output beam of the system by suppressing high-order modes and gaining low-order modes, or mode. The holographic elements are made in the form of rectangular grooves that can be manufactured as binary features reproduced by methods of nanolithography or nanoimprinting.

Abstract: The present invention relates to a light source apparatus having a structure to enable a short pulse optical output with high pulse energy or a high pulse peak equivalent to that of a Q switch laser light source. The light source apparatus comprises a seed light source, a pre-stage optical amplifier, a subsequent-stage optical amplifier, and a control section. After the pulse light outputted from the seed light source is amplified by the pre-stage optical amplifier, the pulse light is amplified further by the subsequent-stage optical amplifier. In the subsequent-stage optical amplifier, a ring-type resonator is constituted by an optical coupler, an optical coupler, an optical amplification waveguide, an optical isolator, an optical coupler, an optical waveguide, a lens, a Q switch, a lens, and an optical waveguide that are disposed sequentially on the propagation path of the pulse light.

Abstract: A laser apparatus with all optical-fiber includes a plurality of pumping light sources in different wave bands and an optical-fiber laser system. The optical-fiber laser system includes an optical fiber at least doped with erbium (Er) element and doped with or not doped with ytterbium (Yb) element according to a need. The optical-fiber laser system outputs a laser light through the pumping light source.

Abstract: A method of operating a fiber amplifier characterized by a spectral gain curve includes providing an input signal at a signal wavelength. The signal wavelength lies within an in-band portion of the spectral gain curve extending from a first in-band wavelength to a second in-band wavelength, the in-band portion being characterized by a first amplitude range. The method also includes providing pump radiation at a pump wavelength. The pump wavelength is less than the signal wavelength. The method further includes coupling the pump radiation to the fiber amplifier and amplifying the input signal to generate an output signal. All portions of the spectral gain curve at wavelengths less than the first in-band wavelength and greater than the pump wavelength are characterized by a second amplitude less than or equal to 10 dB greater than the first amplitude range.

Abstract: In various embodiments, output beams of multiple seed lasers differing in at least one beam characteristic are combined, amplified, and separated according to the beam characteristic(s) for use in, e.g., plateless lithographic printing.

Abstract: A core includes a center core region, a core layer that is formed around the center core region and that has a refractive index lower than that of the center core region, and at least one buffer core layer that is formed between the center core region and the core layer and that has a refractive index lower than that of the center core region and higher than that of the core layer. A cladding is formed around the core layer and that has a refractive index lower than that of the center core region and higher than that of the core layer. An effective core area at a wavelength of 1550 nm is equal to or smaller than 18 ?m2.

Abstract: An apparatus and method for compensating for mode-profile distortions caused by bending optical fibers having large mode areas. In various embodiments, the invention micro-structures the index of refraction in the core and surrounding areas of the inner cladding from the inner bend radius to the outer bend radius in a manner that compensates for the index changes that are otherwise induced in the index profile by the geometry and/or stresses to the fiber caused by the bending.

Abstract: The present disclosure provides an approach to more efficiently amplify signals by matching either the gain materials or the pump profile with the signal profile for a higher-order mode (HOM) signal. By doing so, more efficient energy extraction is achieved.

Abstract: The present invention embraces an optical fiber that includes a central core to transmit optical signals and an optical cladding surrounding the central core to confine transmitted optical signals. The optical fiber typically includes metallic nanostructures for increasing second-order nonlinearity effects. The optical fiber typically has a refractive index profile that ensures a phase-matching condition.

Abstract: Frequency-multiplied fiber-MOPA apparatus includes one enclosure containing a master oscillator and fiber amplifier stages and another enclosure containing frequency-multiplying stages. Radiation is transmitted between the enclosures by a transport fiber in a flexible jacket or enclosure. The transport fiber functions additionally as a power amplifier fiber, and amplifies the radiation while transporting the radiation between the enclosures. The amplifying transport fiber is energized by diode-lasers in the enclosure containing the master oscillator and fiber amplifiers.

Abstract: A chirped pulse amplifier (CPA) system having a mode-locked laser and a high-speed pulse selector, wherein the pulse selector modulates output pulses based upon an applied modulation voltage. A pulse selector may be an integrated electro-optic modulator, for example a LiNbO3 modulator, or an electro-absorption modulator. Difficulties related to free-space alignment and operational stability of some prior designs are reduced or eliminated. Fiber coupling generally simplifies beam delivery and alignment. Some embodiments include an erbium fiber (or erbium-ytterbium) based CPA system operating at a wavelength of approximately 1550 nanometers. Similar performance can be obtained at other wavelengths, for example a 1.06 micrometer Yb-doped fiber system. Moreover, high amplification and peak intensity at the output may be achieved while avoiding non-linear effects in the pulse selector, thereby providing for high intensity picosecond or femtosecond operation.

Abstract: An optical fiber laser, according to the present invention, has an optical fiber including a core to which a rare earth element is added and a clad disposed around the core, and also has an excitation light source for emitting excitation light incident on a side of the optical fiber. The optical fiber has a corrugated shape on the outer circumference of the clad along the longitudinal direction thereof; and the optical fiber is wound in a spiral form and is bundled in such a way that adjacent sides of the clad are brought into contact with one another.

Abstract: A high-power narrow-linewidth fiber laser system includes a seed oscillator with multiple resonant cavities and an amplifier stage. The seed oscillator includes a gain fiber, a pump source to introduce pump light into the gain fiber, a single-mode output fiber arranged at the end of the active gain fiber, a first resonant cavity including the active gain fiber, and a second resonant cavity including the active gain fiber. The first and second resonant cavities cooperate to minimize the synchronization of longitudinal modes and thereby reduce modal beating. The amplifier preferably includes an active multimode gain fiber capable of supporting a single fundamental mode at the signal wavelength, wherein the single mode output fiber of the seed oscillator and the multimode gain fiber of the amplifier are mode-matched and coupled without a mode converter.

Abstract: A chirped pulse amplification (CPA) system comprises an optical pulse stretcher and an optical pulse compressor that are mismatched in that the optical pulse compressor includes a bulk optical grating while the optical pulse stretcher does not. High order dispersion compensation is provided by an optical phase mask disposed within the optical pulse compressor.

Abstract: The present invention provides methods, systems, and apparatus of improved fiber-based optical parametric oscillators (FOPOs). These oscillators can be used in the creation of short pulsed laser radiation, which are useful in numerous applications, such as characterization of materials and molecules. A relationship between fiber length and performance is realized, where shorter lengths counterintuitively provide greater power and width of output bands. This relationship is used to develop improved FOPOs. For example, fibers of 10 cm or less may be used to obtain superior performance in terms of wavelength tunability (e.g. bandwidth of 200 nm and greater) and output power (e.g. pulse power of 1 nJ). Other realized relationships between length and wavelength position of output bands are also used to select the wavelength range output from the FOPO. The diameter of the fiber may be selected to provide positioning (e.g. a centering) of the range of attainable output wavelengths.

Abstract: A laser oscillator includes a ring resonator. The ring resonator includes an optical circulator having first, second, third, and fourth ports and a first optical amplification fiber connected to the optical circulator. Light incident on the first port is exited from the second port, and light incident on the second port is exited from the third port. The fourth port provides an exciting light and injects the exciting light into the ring resonator through the first port. The first optical amplification fiber amplifies light exited from the third port with the exciting light provided by the fourth port. The laser oscillator also includes an optical member connected to the optical circulator. The optical member reflects at least a part of the light exited from the second port and injects the same into the second port again.

Abstract: Guided adiabatic bend transitions for multimode fibers are presented to preserve the power of guided light in the fundamental mode while guiding from one level of curvature to another for improved operation of mode filters and fiber amplifiers. A method is provided to find the guidance path. Implementations of these transducers include modal power back converters, and guidance paths into and out of higher order mode filtering devices which work on bending. A spiral structure is shown to incorporate adiabatic bends for a forward-pumped fiber amplifier.

Abstract: An apparatus for providing communications between a first device disposed at a tubular and a second device, the tubular having tubular sections and being configured to be disposed in a borehole penetrating the earth, the apparatus including: a first optical coupler configured to be concentrically coupled to a first tubular section and configured to be in optical communication with the first device using a first optical transmission medium disposed at the first tubular section; and a second optical coupler configured to be concentrically coupled to a second tubular section and configured to be in optical communication with the second device using a second optical transmission medium disposed at the second tubular section; wherein the first optical coupler is configured to be perimetrically disposed about the second optical coupler to be in communication with the second optical coupler to provide the communications between the first device and the second device.

Abstract: A laser source includes a laser beam generating section for generating a laser beam in a cavity between first reflector and a second reflector; and a tap section provided in the cavity to take out a part of the laser beam. The laser source is a waveguide-based laser source.

Abstract: Master oscillator power amplifier (MOPA) apparatus includes two seed-pulse sources coupled to a single fiber amplifier including one or more stages of amplification. One of the seed-pulse sources is a single-mode source generating pulses having a duration selectively variable between about 0.1 ns and 10 ns. The other seed-pulse source is a multi-mode source generating pulses having a duration selectively variable between about 1 ns and 10 ?s. Selectively operating one or the other of the seed-pulse sources provides that the apparatus can deliver pulses selectively variable in a range between about 0.1 ns and 10 ?s.

Abstract: A fiber laser amplifier system including a master oscillator that generates a signal beam. A splitter splits the signal beam into a plurality of fiber beams where a separate fiber beam is sent to a fiber amplifier for amplifying the fiber beam. A tapered fiber bundle couples all of the output ends of all of the fiber amplifiers into a combined fiber providing a combined output beam. An end cap is optically coupled to an output end of the tapered fiber bundle to expand the output beam.

Abstract: A fiber laser amplifier system including a plurality of master oscillators each generating a signal beam at a different wavelength. A splitter is provided for each master oscillator that splits the signal beam into a plurality of fiber beams where a separate fiber beam is sent to a fiber amplifier. A tapered fiber bundle couples the output ends the fiber amplifiers for each wavelength group into a combined fiber providing a combined output beam, where a separate combined output beam is provided for the wavelength for each master oscillator. An end cap is optically coupled to an output end of each of the tapered fiber bundles to expand the combined output beam. A spectral beam combination grating receives the combined beams from the tapered fiber bundles at different angles and outputs an output beam of all of the combined beams as a single beam being directed in the same direction.

Abstract: An ytterbium-doped optical fiber of the present invention includes: a core which contains ytterbium, aluminum, and phosphorus and does not contain germanium; and a cladding which surrounds this core. The ytterbium concentration in the core in terms of ytterbium oxide is 0.09 to 0.68 mole percent. The molar ratio between the phosphorus concentration in the core in terms of diphosphorus pentoxide and the above ytterbium concentration in terms of ytterbium oxide is 3 to 30. The molar ratio between the aluminum concentration in the core in terms of aluminum oxide and the above ytterbium concentration in terms of ytterbium oxide is 3 to 32. The molar ratio between the above aluminum concentration in terms of aluminum oxide and the above phosphorus concentration in terms of diphosphorus pentoxide is 1 to 2.5.

Abstract: A system and method for utilizing a multi link antenna array for wireless links in conjunction with fiber MAN's is disclosed. The fiber MAN's are coupled to one or more multi-link antenna arrays. Each multi-link antenna array forms a plurality of point-to-point wireless links.

Abstract: An optical amplifier, such as an optical waveguide amplifier (e.g., an optical fiber amplifier or a planar waveguide) or a non-guiding optical amplifier, that exhibits a net phase-mismatch selected to at least partially reduce gain-induced phase-matching during operation thereof is disclosed. In one aspect of the invention, an optical amplifier structure includes at least one optical amplifier having a length and a gain region. The at least one optical amplifier exhibits a net phase-mismatch that varies along at least part of the length thereof selected to at least partially reduce gain-induced phase-matching during operation thereof.

Abstract: Output pulses from an optical system having a seed source and an optical amplifier coupled to the seed source may be controlled by controlling a power of a seed signal from the seed source. The seed signal may be varied between a minimum value and a maximum value in a way that the seed signal exhibits one or more pulse bursts. Each pulse burst may contain one or more pulses. During an inter-pulse period between successive pulses within a pulse burst or between successive pulse bursts, the power of the seed signal may be adjusted to an intermediate value that is greater than the minimum value and less than the maximum value. The intermediate value is chosen to control a gain in the optical amplifier such that a pulse or pulse burst that follows the period exhibits a desired behavior.

Abstract: Included among the many structures described herein are photonic bandgap fibers designed to provide a desired dispersion spectrum. Additionally, designs for achieving wide transmission bands and lower transmission loss are also discussed. For example, in some fiber designs, smaller dimensions of high index material in the cladding and large core size provide small flat dispersion over a wide spectral range. In other examples, the thickness of the high index ring-shaped region closest to the core has sufficiently large dimensions to provide negative dispersion or zero dispersion at a desired wavelength. Additionally, low index cladding features distributed along concentric rings or circles may be used for achieving wide bandgaps.

Abstract: An apparatus and method for compensating for mode-profile distortions caused by bending optical fibers having large mode areas. In various embodiments, the invention micro-structures the index of refraction in the core and surrounding areas of the inner cladding from the inner bend radius to the outer bend radius in a manner that compensates for the index changes that are otherwise induced in the index profile by the geometry and/or stresses to the fiber caused by the bending. Some embodiments of an apparatus and method include a fiber having a plurality of substantially parallel cores, the fiber including a straight section and a curved section; guiding signal light primarily in a second core in the straight section; guiding the signal light from the second core into a first core between the straight section and the curved section; and guiding the signal light primarily in the first core in the curved section.

Abstract: An integrated optical-amplification module includes a housing member, a first input optical terminal configured to receive an optical signal, a second input, optical terminal that can receive a pump light, and an output optical terminal that can output a combined optical signal comprising at least a portion of the optical signal and a portion of the pump light. The integrated optical-amplification module also includes an optical combiner fixedly installed relative to the housing member. The optical combiner can receive the pump light and the optical signal and an optical prism fixedly installed relative to the housing member. The optical combiner can merge the pump light and the optical signal to form the combined optical signal. The optical prism can direct at least a portion of the optical signal through free space to the optical combiner.

Abstract: There is provided a planar optical waveguide element in which an optical waveguide core comprises an inner side core having protruding portions that form a rib structure, and an outer side core that is provided on top of the inner side core and that covers circumferential surfaces of the protruding portions, wherein a refractive index of the outer side core is lower than an average refractive index of the inner side core. The structure of the planar optical waveguide element can be applied even when the core is formed from a material having a higher refractive index than that of a silica glass-based material such as silicon (Si) or silicon nitride (SixNy).

Abstract: Fiber optic amplification in a spectrum of infrared electromagnetic radiation is achieved by creating a chalcogenide photonic crystal fiber (PCF) structure having a radially varying pitch. A chalcogenide PCF system can be tuned during fabrication of the chalcogenide PCF structure, by controlling, the size of the core, the size of the cladding, and the hole size to pitch ratio of the chalcogenide PCF structure and tuned during exercising of the chalcogenide PCF system with pump laser and signal waves, by changing the wavelength of either the pump laser wave or the signal wave, maximization of nonlinear conversion of the chalcogenide PCF, efficient parametric conversion with low peak power pulses of continuous wave laser sources, and minimization of power penalties and minimization of the need for amplification and regeneration of pulse transmissions over the length of the fiber, based on a dispersion factor.

Abstract: An optical fiber for optical amplification has: a core portion doped with at least erbium and aluminum; a cladding portion formed around the core portion and having a refractive index smaller than that of the core portion; a peak value of absorption coefficient of 35 dB/m or greater at a wavelength around 1530 nanometers; normal dispersion characteristics and an effective core area of 20 ?m2 or larger, at a wavelength of 1550 nanometers; and a power conversion efficiency of a conversion from pumping light to amplified light having a wavelength of 1550 nanometers is 30% or more.

Abstract: The invention consists in an amplifying optical fiber comprising a core containing a dopant and a cladding, wherein said core comprises a monomode core intended to propagate an optical signal, quantum dots of a semiconductor material being disposed in or near said monomode core, and a multimode core surrounding the monomode core, intended to receive a pumping signal.

Abstract: Provided is an optical device that includes a ring-shaped optical waveguide and an input/output optical waveguide, and that changes a resonant wavelength of the ring-shaped optical waveguide, in which the ring-shaped optical waveguide includes in part a refractive index control section for controlling a refractive index at a guided wavelength, and the refractive index control section is formed of an optical material having a thermo-optic effect with its sign different from that of an optical material that forms a section of the ring-shaped optical waveguide other than the refractive index control section.

Abstract: The specification describes optical devices and related methods wherein an input mode is converted by multiple LPG mode transformers to produce an output with multiple predetermined modes.

Abstract: There is provided a planar optical waveguide element comprises a core of an optical waveguide; and first Bragg grating pattern and second Bragg grating pattern that are provided on the core, wherein the first Bragg grating pattern and the second Bragg grating pattern are mutually parallel along a propagation direction of guided light.

Abstract: Presented is a method and system for phase locking a multi-stage parallel fiber amplifier. The method comprises receiving a signal beam from a first stage, in one path of the multi-stage fiber amplifier, onto a fiber that is pumped to produce a saturated signal beam that is then output to a second stage that outputs an amplified beam. A characteristic of the of the saturated signal beam is that its phase and amplitude do not substantially change based on the amplitude of the signal beam input onto the fiber. The method further detects a portion of the amplified beam to produce a phase indication of the amplified beam relative to amplified beams of the other paths of the multi-stage fiber amplifier. The method modulates the pump level of the first stage to control the phase of amplified beam, and further controls the phases of the other amplified beams of the other paths to phase lock the multi-stage parallel amplifier.

Abstract: Utilization efficiency of cladding pump light in a cladding pumped optical device is improved by converting higher order modes travelling in the cladding to lower order modes that enter the core region and participate more effectively in the energy exchange process. The mode conversion is achieved by asymmetric perturbations in the optical fiber. The perturbations are preferably produced by making the optical fiber in the gain section of the device cylindrically asymmetric. The asymmetric perturbations can be chosen so that they have negligible effect on the lower mode signal light in the core of the optical fiber.

Abstract: By compensating polarization mode-dispersion as well chromatic dispersion in photonic crystal fiber pulse compressors, high pulse energies can be obtained from all-fiber chirped pulse amplification systems. By inducing third-order dispersion in fiber amplifiers via self-phase modulation, the third-order chromatic dispersion from bulk grating pulse compressors can be compensated and the pulse quality of hybrid fiber/bulk chirped pulse amplification systems can be improved. Finally, by amplifying positively chirped pulses in negative dispersion fiber amplifiers, low noise wavelength tunable seed source via anti-Stokes frequency shifting can be obtained.

Abstract: An optical microresonator system and a sensor are disclosed. The optical microresonator system includes an optical waveguide and an optical microresonator that is directly optically coupled to the optical waveguide. The optical microresonator further includes an optical microcavity that is core coupled to the optical microresonator but not to the optical waveguide.

Abstract: A ring resonator has a first optical waveguide arranged in a loop, a second optical waveguide tangentially connected to the first optical waveguide, and an electrical coil inductively coupled to the first optical waveguide.

Abstract: A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some embodiments, the method and apparatus includes a photonic-crystal fiber or rod (PCF or PCR) optical device having a beam-expanding endcap formed, e.g., by collapsing or otherwise sealing holes of the PCF or PCR. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range).

Abstract: A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.

Abstract: A mode filter for eliminating the propagation of higher-order modes along a section of optical multimode fiber comprises a graded index (GRIN) lens, preferably of a quarter-pitch length, and a pinhole element in the form of a small core fiber. This configuration creates a Fourier spatial filter assembly that removes higher order modes propagating along an optical fiber while capturing the fundamental mode of the optical signal. A section of GRIN fiber is preferably used as the lens, with the small core fiber disposed at the output of the GRIN fiber lens to collect substantially only the on-axis fundamental mode of the optical signal. Since the higher order modes are shifted away from the origin by the GRIN fiber lens, only the fundamental mode signal is captured by the small core fiber.

Abstract: Stimulated Brillouin scattering (SBS) in a photonic crystal fiber is suppressed by doping the individual core segments such that the Brillouin frequency of each segment is sufficiently different from the neighboring segments that Brillouin scattered light from one core segment sees negligible gain from the other core segments, whereby higher power narrow-linewidth optical fiber amplifiers and lasers may be obtained. The optical properties of the guiding medium are preserved through the careful design of the core and the lattice structure.

Abstract: The strain-managed optical waveguide assemblies of the present invention utilize a large-mode-area (LMA) optical fiber that is annealed in a first bending such that the fiber in that configuration has substantially no axial strain. A fiber support member is then used to support the annealed LMA optical fiber in a second bending configuration that forms within the LMA optical fiber an axial strain profile that reduces stimulated Brillouin scattering (SBS) as compared to the first bending configuration, and that also preferably causes the LMA optical fiber to operate in a single mode. The LMA optical fiber may have a double-clad configuration and include a doped core that serves as a gain medium. The strain-managed optical waveguide assembly can then be used to constitute a fiber amplifier that mitigates the SBS penalty associated with high-power fiber-based optical systems.

Abstract: An optical component including an acceptance fiber, e.g. a photonic crystal fiber, for propagation of pump and signal light, a number of pump delivery fibers and a reflector element that reflects pump light from the pump delivery fibers into the acceptance fiber. An optical component includes a) a first fiber having a pump core with an NA1, and a first fiber end; b) a number of second fibers surrounding the pump core of the first fiber, at least one of the second fibers has a pump core with an NA2 that is smaller than NA1, the number of second fibers each having a second fiber end; and c) a reflector element having an end-facet with a predetermined profile for reflecting light from at least one of the second fiber ends into the pump core of the first fiber.

Abstract: A high power integrated fiber laser system includes cascaded amplifiers that utilize low numerical aperture fiber amplifiers. The system is rugged and lightweight.