Abstract: A method of manufacturing a wavelength conversion element can control a formation process of a polarization inversion structure with single crystalline magnesium-doped lithium niobate having a congruent composition, and can stably manufacture wavelength conversion elements having high conversion efficiency. The method involves forming periodic electrodes on the +z face of an MgLN substrate and forming an opposite electrode on the ?z face of the MgLN substrate; heat-treating the substrate after forming the periodic electrodes and the opposite electrode; and applying a pulsed electric field between the periodic electrodes and the opposite electrode while holding the MgLN substrate at a temperature of 100° C. or higher. The wavelength conversion element has a polarization inversion structure formed by applying an electric field to a heat-treated MgLN substrate.

Abstract: A wavelength conversion device includes a base substrate having a transparent electrode on one surface thereof and a ferroelectric single crystal substrate provided with an optical waveguide. The ferroelectric single crystal substrate has an insulating film formed on one surface and is bonded to the base substrate such that the insulating film faces the transparent electrode.

Abstract: An optical communication network includes a plurality of optical transmission devices, a communication path, an optical repeater, and a supervisory controller that includes a supervisory control information sender which is installed on at least one of one of the optical transmission devices and the optical repeater and controls a drive signal supplied to a semiconductor optical amplifier that amplifies and outputs input signal light onto the communication path on the basis of the supervisory control information, and a supervisory control information receiver that receives the light which has been output from a semiconductor optical amplifier and transmitted through the communication path, converts the received light to an electric signal and identifies the supervisory control information on the basis of an intensity-modulated component of the total power of the electric signal in at least the other of one of the optical transmission devices and the optical repeater.

Abstract: An optical integration circuit includes a semiconductor optical amplifier (SOA), a readout mechanism coupled to the SOA, and an optical filter coupled to an output of the SOA. The SOA has a decaying response function and an input for receiving an optical input signal having a first wavelength. The SOA is configured to output an optical signal representing a temporal integration of the optical input signal. The readout mechanism provides an optical readout signal having a second wavelength to the SOA for measuring a state of the SOA. The optical filter is configured to receive the signal representing the temporal integration of the optical input signal and block optical signals having the first wavelength.

Abstract: An optical transmission system is provided. The optical transmission system includes a user side optical repeater device (ORD), a central office side ORD, and wavelength multiplexing and wavelength de-multiplexing functions (MUX/DEMUX). The user side optical repeater device (ORD) is to be connected with a user side optical network unit (ONU), transmits data in two ways, and is used for wavelength division multiplexing (WDM). The central office side ORD is to be connected with a central office side optical line terminal (OLT), transmits data in two ways, and is used for WDM. The wavelength multiplexing and a wavelength de-multiplexing functions (MUX/DEMUX), are used for relaying between the user side ORD and the central office side ORD.

Abstract: A health monitoring system includes a waveguide that receives a wave transmitted from an external power source and that guides the wave to reach within a width of a rectenna. The waveguide may include a negative refractive index medium and/or a surface plasmon medium.

Abstract: A method of sustaining a plasma, by focusing a first wavelength of electromagnetic radiation into a gas within a volume, where the first wavelength is substantially absorbed by a first species of the gas and delivers energy into a first region of a plasma having a first size and a first temperature. A second wavelength of electromagnetic radiation is focused into the first region of the plasma, where the second wavelength is different than the first wavelength and is substantially absorbed by a second species of the gas and delivers energy into a second region of the plasma region within the first region of the plasma having a second size that is smaller than the first size and a second temperature that is greater than the first temperature.

Abstract: A method for transferring a thin layer from a lithium-based first substrate includes proton exchange between the first substrate and a first electrolyte, which is an acid, through a free face of the first substrate so as to replace lithium ions of the first substrate by protons, in a proportion between 10% and 80%, over a first depth e1. A reverse proton exchange between the first substrate and a second electrolyte, through the free face is carried out so as to replace substantially all the protons with lithium ions over a second depth e2 smaller than the first depth e1, and so as to leave an intermediate layer between the depths e1 and e2, in which intermediate layer protons incorporated during the proton exchange step remain. The depth e2 defines a thin layer between the free face and the intermediate layer. A heat treatment is carried out under conditions suitable for embrittling the intermediate layer and the thin film is separated from the first substrate at the intermediate layer.

Abstract: A fast switching arbitrary frequency light source for broadband spectroscopic applications. The light source may operate near 1.6 um based on sideband tuning using an electro-optic modulator driven by an arbitrary waveform generator. A Fabry-Perot filter cavity selects a single sideband of the light source. The finesse (FSR/??FWHM) of the filter cavity may be chosen to enable rapid frequency switching at rates up to 5 MHz over a frequency range of 40 GHz (1.3 cm?1). The bandwidth, speed and spectral purity are high enough for spectroscopic applications where rapid and discrete frequency scans are needed. Significant signal-to-noise advantages may be realized using the rapid and broadband scanning features of this system in many areas of spectroscopy, e.g., process monitoring and control, reaction dynamics, and remote sensing (e.g., greenhouse gas monitoring, biological/chemical agent screening).

Abstract: An electromagnetic wave emission device includes a nonlinear crystal, a prism, and a cylindrical lens. The nonlinear crystal has an optical waveguide, receives exciting light having at least two wavelength components, and outputs an electromagnetic wave having a frequency equal to or more than 0.01 [THz] and equal to or less than 100 [THz] by means of the Cherenkov phase matching. The prism includes an electromagnetic wave input surface receiving the electromagnetic wave from the optical waveguide and an electromagnetic wave transmission surface through which the electromagnetic wave which has entered from the electromagnetic wave input surface passes. The cylindrical lens has two bottom surfaces opposed to each other, a flat surface intersecting with the two bottom surfaces, and a curved surface intersecting with the two bottom surfaces and the flat surface, wherein the flat surface is in contact with the electromagnetic wave transmission surface.

Abstract: According to the present invention, an electromagnetic wave emission device includes a nonlinear crystal having an optical waveguide; and a prism including an electromagnetic wave input surface and an electromagnetic wave transmission surface. The electromagnetic wave transmission surface includes a rotation surface which is a trajectory of a tilted line segment rotated about a central axis of the electromagnetic wave input surface, the tilted line segment being tilted with respect to the central axis. The tilted line segment and the central axis are on the same plane. The central axis is in parallel to an extending direction of the optical waveguide. The central axis passes through a projection of the optical waveguide into the electromagnetic wave input surface.

Abstract: A new method for making a nonlinear optical structure for frequency conversion and for using that structure for frequency conversion is described. The nonlinear optical structure is made by depositing alternating contiguous layers of gallium arsenide and aluminum gallium arsenide onto a gallium arsenide substrate. Optical frequency conversion is performed by transmitting a pump laser beam through the structure. The new method is easier to perform than prior art methods.

Abstract: A laser light source includes a fundamental laser generator that generates a fundamental laser light, a wavelength conversion element that is made of a ferroelectric crystal with a periodically poled structure and converts the fundamental laser light to a laser light having a different wavelength, a holding member that holds at least a part of an element surface of the wavelength conversion element that crosses a polarization direction of the periodically poled structure, and an insulation layer that is provided between the holding member and the element surface. Electric resistivity of the insulation layer is 1×108 ?·cm or higher.

Abstract: An optical waveguide device includes a ferroelectric layer having a thickness of 4 ?m-7 ?m; a supporting body; and an adhesive layer adhering a bottom face of the ferroelectric layer and supporting body. The ferroelectric layer includes a ridge comprising a channel optical waveguide, first and second protuberances on opposite sides of the ridge, inner grooves between the ridge and protuberances, respectively, and outer grooves outside of the protuberances, respectively. The outer groove is deeper than the inner groove. The ridge portion has a width of 6.6 ?m-8.5 ?m, a distance of an outer edge of the first protuberance and an outer edge of the second protuberance is 8.6 ?m-20 ?m, the inner groove has a depth of 2.0 ?m-2.9 ?m, and the outer groove has a depth of 2.5 ?m-3.5 ?m.

Abstract: Tunable resonator systems and methods for tuning resonator systems are disclosed. In one aspect, a resonator system includes an array of resonators disposed adjacent to a waveguide, at least one temperature sensor located adjacent to the array of resonators, and a resonator control electronically connected to the at least one temperature sensor. Each resonator has a resonance frequency in a resonator frequency comb and channels with frequencies in a channel frequency comb are transmitted in the waveguide. Resonance frequencies in the resonator frequency comb are to be adjusted in response to ambient temperature changes detected by the at least one temperature sensors to align the resonance frequency comb with the channel frequency comb.

Abstract: The invention relates to a method for coupling a first and second laser (1, 2) having an adjustable difference of their pulse frequencies, which is not equal to zero, wherein the method comprises the following steps: derivation of a first harmonic signal and a signal of the Mth harmonic from the time progression of the light intensity of the pulses emitted by the first laser, mixing of the first harmonic signal and the signal of the Mth harmonic, in order to obtain a first mixed signal, derivation of a second harmonic signal and a signal of the Nth harmonic from the time progression of the light intensity of the pulses emitted by the second laser, mixing of the second harmonic signal and the signal of the Nth harmonic, in order to obtain a second mixed signal, wherein the first and second harmonic signal and the Mth and Nth harmonic are selected in such a manner that the frequencies of the first and second mixed signal are identical, wherein the method furthermore comprises regulation of the pulse frequen

Abstract: A terahertz electromagnetic wave generating element can include a generation layer, and a plurality of pairs of layer structures provided on opposite sides thereof. The layer structures are each provided with a first layer, a second layer on the side of the first layer opposite to the generation layer, and a first grating and a second grating, and having a grating period smaller than the wavelength of the terahertz electromagnetic wave to be used. The first and second gratings are configured so that the refractive index of a medium between the first layer and the second layer continuously varies between a first refractive index and a second refractive index. The thickness of the first and second layers and the grating period, and the grating height are determined so that a terahertz electromagnetic wave having a desired bandwidth with respect to a central wavelength of the terahertz electromagnetic wave generated by the generation layer can be generated.

Abstract: A device for reducing time distortion generated in light pulses by an optical frequency converter including at least one nonlinear optical component (4) having a nonlinear optical susceptibility ? of about 2 or 3, the converter being capable of receiving at least one incident pulse light beam (2), the incident light pulses having a duration ?t0, an optical frequency ?0±??0 and an intensity I0(t), and of generating, by frequency conversion, at least one output pulse beam (3), the output light pulses having a duration ?t1, an optical frequency ?1±??1 different from ?0±??0, and an intensity I1(t). The time distortion-reducing device includes a pre-compensation linear time filter (5) provided on the path of the incident beam (2), and capable of reducing the intensity time distortions generated in the frequency-converted output light pulses to at least one pre-compensation intensity Icomp.

Abstract: A system and method for improving conversion efficiency of a difference frequency generator (DFG) and/or for outputting a desired shape of the output signal, where the method includes providing a pump source, modifying the pump pulse temporal shape for optimal DFG conversion efficiency, and providing the modified pump pulse to the DFG. The pump source may be, for example, a MOPA laser or a diode or any other suitable source. In one embodiment, the pump pulse shape is modified such that an initial gain within the DFG is high, followed by a lower level signal for efficient conversion within the DFG. An example of such a shape is a double square pulse. Other configurations are possible as well such as a single rectangular pulse shape.

Abstract: A probe light source produces probe light having a second wavelength different from a first wavelength of signal light. To a light modulator, the probe light and signal light produced from the probe light source are supplied. The light modulator multiplexes the probe light and signal light produced from the probe light source, and supplies it to a nonlinear optical medium. Further, the light modulator modulates the probe light by an intensity change of the signal light in the nonlinear optical medium, and outputs modulated light having the second wavelength based on the data of the signal light.

Abstract: An integrated semiconductor optical device includes first and second semiconductor optical devices. The first semiconductor optical device includes a first core layer, a first upper cladding layer including a first ridge portion, a first buried layer surrounding the first ridge portion, and a first adjusting layer provided between the first buried layer and the first ridge portion. The second semiconductor optical device includes a second core layer, a second upper cladding layer including a second ridge portion. The first semiconductor optical device and the second semiconductor optical device are arranged next to each other in a predetermined axis direction. The first core layer is joined to the second core layer by a butt joint method at a joint boundary between the first and second semiconductor optical devices. The first adjusting layer has a refractive index lower than a refractive index of the first core layer and higher than a refractive index of the first buried layer.

Abstract: An electromagnetic wave generating device is provided which includes an optical waveguide including a plurality of waveguide segments such that the main lobe of a combined electromagnetic wave has a substantially single large directivity. The electromagnetic wave generating device includes the optical waveguide including a plurality of waveguide segments each of which is sandwiched between dielectrics and includes a nonlinear optical crystal. The waveguide segments are arranged such that an angle formed by the directions of propagation of light in the two adjacent waveguide segments substantially corresponds to 2?c. When ng denotes the refractive index of the nonlinear optical crystal for light and ?eff denotes the effective relative permittivity of an assembly of the dielectrics and the waveguide segments for an electromagnetic wave, ?c is defined as ?c=cos?1 (ng/???eff).

Abstract: An integrated semiconductor optical device includes first and second semiconductor optical devices. The first semiconductor optical device includes a first core layer, a first upper cladding layer including a first ridge portion, a first buried layer surrounding the first ridge portion, and a first adjusting layer provided between the first buried layer and the first ridge portion. The second semiconductor optical device includes a second core layer, a second upper cladding layer including a second ridge portion. The first semiconductor optical device and the second semiconductor optical device are arranged next to each other in a predetermined axis direction. The first core layer is joined to the second core layer by a butt joint method at a joint boundary between the first and second semiconductor optical devices. The first adjusting layer has a refractive index lower than a refractive index of the first core layer and higher than a refractive index of the first buried layer.

Abstract: This invention provides devices and methods for broad-band amplification of non linear properties. This invention provides devices comprising optically non linear material that is in contact with a slit array. The slit array causes enhancement of the electromagnetic field within the non linear materials. The enhancement of the electromagnetic field within the optically non linear material results in an amplified non linear response exhibited by the optically non linear materials. This invention provides detectors and imaging systems based on devices and methods of this invention.

Abstract: A laser source includes a laser device configured to emit laser light at a given angle with respect to a normal of an output end face; and an optical device configured to include an optical waveguide that guides and outputs the laser light. The output end face of the laser device is parallel to an input end face of the optical device, and the optical waveguide extends in a direction of ?w1 that is given by ?w1=arcsin(sin ?a1/nF), where ?a1 denotes an outgoing angle of the laser light from the laser device, and nF denotes an effective refractive index of the optical waveguide for the laser light.

Abstract: An optical crystal includes a first non-linear optical crystal that generates terahertz waves corresponding to a difference frequency component in incident light with two different wavelengths by a difference frequency generation, and a second non-linear optical crystal that generates terahertz waves corresponding to a difference frequency component in incident light with two different wavelengths by a difference frequency generation, the second non-linear optical crystal being different in material from the first non-linear optical crystal, and the first non-linear optical crystal and the second non-linear optical crystal being disposed in contact or close together.

Abstract: A waveguide device for frequency mixing or conversion through birefringent phase matching, having two suspended horizontal waveguides with an air-filled horizontal nanoslot between them. The waveguides are formed of a material with a high nonlinear susceptibility, and one waveguide can be n-doped with the other waveguide slab being p-doped. The system can be tuned to operate at different frequencies by varying the nanoslot gap distance by electrostatically actuating the suspended air-clad waveguides.

Abstract: A leaky travelling wave array of optical elements provide a solar wavelength rectenna.

Abstract: A high index contrast waveguide based source for radiation. In some embodiments, the radiation is in the 0.5-14 Terahertz regime. Waveguides are provided that permit the generation of radiation at the sum and/or difference frequency of two input beams. In order to control the power level within the waveguide, embodiments in which pluralities of similar or identical waveguide are provided, and the input radiation is divided among the plurality of waveguides. The output radiation can be steered by applying phased array methods and principles.

Abstract: Wavelength converters for solid state lighting devices, and associated systems and methods. A system in accordance with a particular embodiment includes a solid state radiative semiconductor structure having a first region and a second region. The first region is positioned to receive radiation at a first wavelength and has a first composition and an associated first bandgap energy. The second region is positioned adjacent to the first region to receive energy from the first region and emit radiation at a second wavelength different than the first wavelength. The second region has a second composition different than the first composition, and an associated second bandgap energy that is less than the first bandgap energy.

Abstract: A device of oscillating an electromagnetic wave having a frequency of 0.1 THz to 3 THz from pump and idler waves by parametric effect. The device includes a supporting body, an oscillating substrate of a non-linear optical crystal, an adhesive layer adhering the supporting body and the oscillating substrate, and a film for reflecting the electromagnetic wave formed on a surface of the supporting body on the side of the adhesive layer. The oscillating substrate has an upper face, a bottom face and an incident face on which the pump wave is made incident, with the adhesive layer having a refractive index with respect to the pump wave lower than that of the oscillating substrate.

Abstract: An oscillating device includes an oscillating substrate of a non-linear optical crystal and having an incident face where a pump wave and an idler wave are made incident; a first waveguide provided in the oscillating substrate and between the incident face and an interacting part of the pump wave and idler waves; and a second waveguide provided in the oscillating substrate and between the incident face and the interacting part. The first waveguide guides the pump wave and the second waveguide guides the idler wave.

Abstract: A nonlinear optic article for difference frequency generation is provided. The article comprises a wave mixer configured to generate a difference frequency mixing signal, the wave mixer comprising a compound made from one or more noncentrosymmetric crystal-glass phase-change materials comprising one or more chalcogenide compounds that are structurally one dimensional and comprise a polymeric 1?[PSe6?] chain or a polymeric 1?[P2Se62?] chain, wherein the one or more chalcogenide compounds are capable of difference frequency generation.

Abstract: A method for controlling the nonlinear moments of a nonlinear optical material of an electrooptical device is disclosed. The method includes controlling an optical mode region of the electrooptical device by providing a time varying signal to the electrooptical device via one or more electrodes of the device and affecting the nonlinear moments of the nonlinear optical material of the electrooptical device by providing a time independent bias to the device. In one embodiment, the nonlinear optical material includes a ?3 material. In another embodiment, the method includes employing the time independent bias to bias the ?3 material such that the ?3 material behaves in a manner analogous to a ?2 material.

Abstract: A frequency comb generator fabricated on a chip with elimination of a disadvantageous reflow process, includes an ultra-high Q disk resonator having a waveguide that is a part of a wedge structure fabricated from a silicon dioxide layer of the chip. The disk resonator allows generation of a frequency comb with a mode spacing as low as 2.6 GHz and up to 220 GHz. A surface-loss-limited behavior of the disk resonator decouples a strong dependence of pumping threshold on repetition rate.

Abstract: A device for oscillating an electromagnetic wave having a frequency of 0.1 THz to 3 THz from pump and idler waves by a parametric effect. The device includes a supporting body, an oscillating substrate made of a non-linear optical crystal, and an adhesive layer adhering the supporting body and oscillating substrate. The oscillating substrate includes an upper face, a bottom face and an incident face on which the pump wave is made incident. The oscillating substrate provides cut-off with respect to the electromagnetic wave oscillated by the parametric effect when the pump and idler waves propagate in parallel with the bottom face.

Abstract: The invention relates to an optical regenerator for a differential phase modulated data signal which comprises, in addition to a unit for bit-by-bit gauge leveling, a unit for the regeneration of the phase of individual symbols of the differential phase modulated data signal. After the bit-by-bit gauge leveling, the data signal that is preset in amplitude is divided into a first and a second data signal. Phase errors of individual signals are detected for the first data signal in a phase error detection unit, are transformed into a correction signal, and are conveyed to a phase error correction unit. The second data signal is corrected in the phase error correction unit, depending on the correction signal conveyed thereto in the phase of said data signal, in such a way that a differential phase modulated data signal, regenerated in amplitude and in phase, is delivered at the output of the correction unit.

Abstract: A wavelength conversion device has a supporting body, a wavelength conversion substrate, a lower side buffer layer provided on the side of a bottom face of the substrate, a upper side buffer layer provided on the side of a upper face of the substrate, and an adhesive layer adhering the supporting body 8 and the lower side buffer layer. The wavelength conversion substrate is made of a Z-plate of a ferroelectric single crystal and a periodic polarization inversion structure formed therein. The supporting body has a volume resistivity lower than that of the ferroelectric single crystal of the wavelength conversion substrate.

Abstract: A device for increasing the spectral bandwidth of optical pulses, comprises a hollow fiber waveguide, optical components for focusing the beam into the hollow fiber waveguide and for re-collimating the beam at the exit of the hollow fiber waveguide, the hollow fiber waveguide being contained in an air-tight chamber filled with a gas at a given pressure; the length of the hollow fiber is such that, for a given input pulse energy and gas pressure, the energy contained in a fundamental propagation mode of the optical pulses that has minimum propagation losses exhibits substantially periodic oscillations over the full length of the hollow fiber waveguide and reaches a local maximum at the output end of the said hollow fiber waveguide.

Abstract: A method of fixing a polarization-reversed region formed in a ferroelectric single crystal, including preparing a ferroelectric single crystal having a polarization-reversed region; and irradiating an ion beam or a neutral beam on the ferroelectric single crystal. The ferroelectric single crystal is a substantially stoichiometric lithium tantalate single crystal or a substantially stoichiometric lithium niobate single crystal, and the polarization-reversed region is fixed and any back switch and expansion of the polarization-reversed region are suppressed.

Abstract: An optical signal processing device includes a waveform width widening unit configured to widen a waveform width of an optical signal; and an optical limiter circuit, to which the optical signal the waveform width of which is widened is input, configured to suppress an intensity of the optical signal in a region where an input intensity and an output intensity are not proportional.

Abstract: A method, a device, and a system for realizing data transmission extension in a passive optical network (PON) are provided. Between a burst-mode clock and data recovery (BCDR) module and an electrical-optical (E/O) amplification module, the device includes a delimiter matching module and a preamble buffering and compensating module. The delimiter matching module is adapted to receive a data frame sent by the BCDR module and determine a location of a delimiter in the data frame. An optical-electrical (O/E) amplification module performs O/E conversion, amplification, and shaping on the data frame. The BCDR module then performs clock and data recovery processing on the data frame.

Abstract: A harmonic wave oscillating device having a supporting body, a wavelength converting layer, a lower side adhesive layer that adheres the wavelength converting layer and the supporting body, an upper side substrate provided on the side of an upper face of the wavelength converting layer, and an upper side adhesive layer that adheres the wavelength converting layer and the upper side substrate. The wavelength converting layer is made of a ferroelectric single crystal and has a channel type optical waveguide with a periodic polarization inversion structure formed therein. The wavelength converting layer has a width of 1.5 mm or smaller when viewed in a direction parallel to the wavelength converting layer and perpendicular to light propagating in the optical waveguide, and at least one of the supporting body and the upper side substrate has a volume resistivity lower than that of the ferroelectric single crystal.

Abstract: A laser assembly is configured with a frequency conversion laser head operative to shift a fundamental frequency of input light to the desired frequency of an output light. The frequency conversion laser head includes a dump means operative to guide an unconverted output light at the fundamental frequency outside the case of the frequency conversion laser head. The dump means is configured with a guide optics operative to couple the output light at the fundamental frequency to a fiber terminating outside the case of the frequency conversion laser head.

Abstract: A waveguide parametric device including a multi-mode waveguide having orientation layers formed in a propagation direction of a signal beam and a pump beam propagating down the waveguide. The orientation layers are oppositely oriented to provide non-linear coupling between the pump beam and the signal beam and have a periodicity that provides quasi-phase matching for a fundamental propagation mode, where the waveguide has a size to accommodate multi-mode wave propagation.

Abstract: A light emitting apparatus has a radiation source for emitting short wavelength radiation. A down conversion material receives and down converts at least some of the short wavelength radiation emitted by the radiation source and back transfers a portion of the received and down converted radiation. An optic device adjacent the down conversion material at least partially surrounds the radiation source. The optic device is configured to extract at least some of the back transferred radiation. A sealant substantially seals a space between the radiation source and the optic device.

Abstract: A new nonlinear optical structure for frequency conversion is described. The new nonlinear optical structure is a multilayer wafer comprising alternating layers of gallium arsenide and aluminum gallium arsenide onto a gallium arsenide substrate. The new device is both more efficient and easier to make than prior art gallium arsenide crystal structures designed for nonlinear optical conversion.

Abstract: A wavelength converter is provided with an infrared light source (1) for emitting a fundamental wave having a wavelength of 2000 nm or shorter, a wavelength conversion element (3) composed of a nonlinear optical crystal having a periodical polarization reversal structure and adapted to convert a fundamental wave emitted from the infrared light source (1) into a harmonic wave, and a heater (4) for heating the wavelength conversion element (3). The period of the polarization reversal structure is designed so that a quasi phase matching temperature of the fundamental wave and the harmonic wave is 40° C. or higher. The heater (4) heats the wavelength conversion element (3) to a temperature at which quasi phase matching is established, and the nonlinear optical crystal contains a lithium niobate or lithium tantalate including at least any one of additives Mg, In, Zn and Sc as a main component. Thus, optical damage can be suppressed and visible light absorption attributed to ultraviolet light can be reduced.

Abstract: Methods of positioning an optical unit in an optical package are provided. According to one method, a partially assembled optical package is provided. The wavelength conversion device within the package comprises a conversion layer having a waveguide portion formed therein. The optical unit is coarse-positioned in the optical package to direct light from the laser diode to the wavelength conversion device in the form of a beam spot on an input face of the wavelength conversion device. The intensity of the frequency-converted optical signal output from the wavelength conversion device is monitored as the position of the optical unit is modified to 1D scan the beam spot along a portion of a crossing axis Y1 that crosses a planar projection of the conversion layer of the wavelength conversion device. Subsequently, the crossing axis Y1 is offset and the intensity monitoring step is repeated as the beam spot is 1D scanned along an offset crossing axis Y2.

Abstract: Use of quasi-phase-matched (QPM) materials for parametric chirped pulse amplification (PCPA) substantially reduces the required pump peak power and pump brightness, allowing exploitation of spatially-multimode and long duration pump pulses. It also removes restrictions on pump wavelength and amplification bandwidth. This allows substantial simplification in pump laser design for a high-energy PCPA system and, consequently, the construction of compact diode-pumped sources of high-energy ultrashort optical pulses. Also, this allows elimination of gain-narrowing and phase-distortion limitations on minimum pulse duration, which typically arise in a chirped pulse amplification system. One example of a compact source of high-energy ultrashort pulses is a multimode-core fiber based PCPA system. Limitations on pulse energy due to the limited core size for single-mode fibers are circumvented by using large multimode core.