Abstract: Titania is a semiconductor and photocatalyst that is also chemically inert. With its bandgap of 3.0, to activate the photocatalytic property of titania requires light of about 390 nm wavelength, which is in the ultra-violet, where sunlight is very low in intensity. A method and devices are disclosed wherein stress is induced and managed in a thin film of titania in order to shift and lower the bandgap energy into the longer wavelengths that are more abundant in sunlight. Applications of this stress-induced bandgap-shifted titania photocatalytic surface include photoelectrolysis for production of hydrogen gas from water, photovoltaics for production of electricity, and photocatalysis for detoxification and disinfection.

Abstract: An optical memory includes an array of optical material and a beam scanning device. The optical material assumes first and second states, and incident light causes the optical material to transition from the first state to the second state. The beam scanning device selectively directs a received optical data signal across the array of optical material.

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 wavelength division multiplexing system according to the present art adjusts the amount of dispersion compensation (the amount of dispersion compensation of an NZ-DSF and a DCF) every all spans on the basis of the time slot when an intensity modulation signal transmitter outputs an intensity modulation signal and the wavelength interval when a wavelength coupler multiplexes a phase modulation signal (output from a phase modulation signal transmitter) and the intensity modulation signal.

Abstract: A waveguide having a spatially-variable refractive index is disclosed. The waveguide having a spatially-variable refractive index comprises a light-propagating medium and a non-uniform distribution of liquid crystal material in a matrix of dielectric material located in a portion of the light-propagating medium.

Abstract: A modulator includes an electro-optical substrate and a first and second waveguide formed of a doped semiconductor material positioned on a surface of an electro-optical substrate forming a slot therebetween. A doping level of the semiconductor material being chosen to make the first and second waveguide conductive. A dielectric material is positioned in the slot which increases confinement of both an optical field and an electrical field inside the slot. A refractive index of the semiconductor material and a refractive index of the dielectric material positioned in the slot being chosen to reduce the V?·L product of the modulator.

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 all-fiber optical pulse compression arrangement comprises a concatenated arrangement of a section of input fiber (e.g., a single mode fiber), a graded-index (GRIN) fiber lens and a section of pulse-compressing fiber (e.g., LMA fiber). The GRIN fiber lens is used to provide mode matching between the input fiber (supporting the propagation of chirped optical pulses) and the pulse-compressing fiber, with efficient pulse compression occurring along the length of the LMA fiber. The dispersion and length of the LMA fiber section are selected to provide the desired degree of pulse compression; for example, capable of reconstituting a femtosecond pulse as is used in supercontinuum generation systems.

Abstract: A frequency-conversion method that uses a nonlinear optical process to transfer energy between a surface-plasmon (SP) wave that is guided along an electrically conducting strip and a light beam that is guided along an optical waveguide whose core is adjacent to the electrically conducting strip. A periodic structure spatially modulates the nonlinear susceptibility of the waveguide core with a spatial period that is related to a momentum mismatch in the nonlinear optical process. The spatial modulation provides quasi-phase matching for the SP wave and the light beam and enables efficient energy transfer between them.

Abstract: An optical fiber, which has a zero-material dispersion wavelength equal to or greater than 2 ?m, and a high nonlinear susceptibility ?3 equal to or greater than 1×10?12 esu, and uses tellurite glass having sufficient thermal stability for processing into a low loss fiber, employs a PCF structure or HF structure having strong confinement into a core region. This enables light to propagate at a low loss. The size and geometry of air holes formed in the core region, and the spacing between adjacent air holes make it possible to control the zero dispersion wavelength within an optical telecommunication window (1.2-1.7 ?m), and to achieve large nonlinearity with a nonlinear coefficient ? equal to or greater than 500 W?1 km?1.

Abstract: An optical communications link is described, comprising first and second fiber lines in substantial scaled translational symmetry by a common scaling factor with respect to a second-order dispersion coefficient profile (oppositely signed) and with respect to at least one of a loss/gain coefficient profile and a nonlinear coefficient-power product profile for facilitating progressive compensation along the second fiber line of at least one nonlinearity introduced along the first fiber line.

Abstract: A wavelength converter which performs simultaneously wavelength conversion for a plurality of input light wavelengths that are unequally intervals, is provided. The nonlinear material of the wavelength converter has a modulation structure which has modulation of a nonlinear optical constant at a period ?0 in a propagating direction of light, a phase being continuously changed each period ?0 and a continuous phase modulation for a different period ?ph being added to the modulation structure. The nonlinear material has a modulation structure obtained by changing a modulation curve for the phase modulation, wherein a phase mismatch ?? is represented by ??=2?(n3/?3?n2/?2?n1/?1), and at least three peaks at unequally intervals within a plurality of peaks for conversion efficiency represented by 2?/?0+2?i/?f (i=m, m+1, . . . , n: where m and n are positive or negative integers) have highest conversion efficiency.

Abstract: Devices, systems and methods of using same where hybrid substrate materials are provided with a substantially uniform surface to provide uniformity of properties, including interaction with their environments. Uniform surfaces are applied as coatings over, e.g., hybrid metal/silica, metal/polymer, metal/metal surfaces to mask different chemical properties of differing regions of the surface and to afford a protective surface for the hybrid structure.

Abstract: Devices, systems and methods of using same where hybrid substrate materials are provided with a substantially uniform surface to provide uniformity of properties, including interaction with their environments. Uniform surfaces are applied as coatings over, e.g., hybrid metal/silica, metal/polymer, metal/metal surfaces to mask different chemical properties of differing regions of the surface and to afford a protective surface for the hybrid structure.

Abstract: Poling structures and methods utilizing an electrostatic field generated from a polar dielectric material, including pyroelectric and ferroelectric materials, to produce electro-optic activity in organic nonlinear optical materials.

Abstract: An optical logic gate (10) comprises: first and second optical inputs (11, 12) for receiving respective optical signals (A, B) and an optical output (15) for outputting an optical signal (Pout) which represents the result of applying a required logic function. The logic gate is characterized by optical combining means (13) for combining the optical signals to produce a corresponding combination signal whose power (Pi) is the combination of the powers (PA, PB) of the optical signals and non-linear optical means (14) for receiving the combination signal (Pi) and emitting the optical output signal (Pout) the logic function depending on the characteristic of the non-linear optical means wherein the characteristic is selected such that the power of the output signal is correlated to the power of the combination signal by the selected logic function.

Abstract: This disclosure presents a version of a coherent laser radar system that is immune to environmental effects on Mach-Zehnder-configured interferometers and reference length standards comprising such systems. The present disclosure also describes methods and materials which alleviate interferometer drift due to vapor absorption using a polyimide coated polarization maintaining fiber to reduce the change in the length of a reference arm.

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: The present invention relates to a single mode optical fiber comprising a first central region having a radius r1, a maximum refractive index value n1 and at least one second ring surrounding said first central region, which second ring has a radius r2 and a minimum refractive index value n2, wherein n2<n1. The present invention furthermore relates to an optical communication system for multi-channel signal transmission.

Abstract: An optical frequency converter that uses a nonlinear optical process to transfer energy between a surface-plasmon (SP) wave that is guided along an electrically conducting strip and a light beam that is guided along an optical waveguide whose core is adjacent to the electrically conducting strip. The optical frequency converter has a periodic structure that spatially modulates the nonlinear susceptibility of the waveguide core with a spatial period that is related to a momentum mismatch in the nonlinear optical process. The spatial modulation provides quasi-phase matching for the SP wave and the light beam and enables efficient energy transfer between them.

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: A harmonic wave oscillating system includes a solid-state laser oscillator, a converting waveguide converting a wavelength of a laser light oscillated from the solid-state laser oscillator to oscillate a harmonic wave, an incident-side end face of the laser light, an emitting-side end face of the harmonic wave, a first side face and a second side face. The emitting-side end face includes a polished surface 6 formed on the side of the first side face 1a and a light scattering surface formed on the side of the second side face 1b. The first side face 1a and polished surface 6 are intersected at an obtuse angle ?, and the second side face 1b and light scattering surface 5 are intersected at an obtuse or right angle ?.

Abstract: An apparatus and methods for generating a substantially supercontinuum-free widely-tunable multimilliwatt source of radiation characterized by a narrowband line profile. The apparatus and methods employ nonlinear optical mechanisms in a nonlinear photonic crystal fiber (PCF) by detuning the wavelength of a pump laser to a significant extent relative to the zero-dispersion wavelength (ZDW) of the PCF. Optical phenomena employed for the selective up-conversion in the PCF include, but are not limited to, four-wave mixing and Cherenkov radiation. Tunability is achieved by varying pump wavelength and power and by substituting different types of PCFs characterized by specified dispersion properties.

Abstract: A fiber optic device outputs, at high conversion efficiency, an idler lightwave having a wavelength ?2 different from the wavelength of a signal lightwave by converting the signal lightwave having an optional wavelength ?1 in a wide wavelength band. The fiber optic device comprises a wavelength tunable pump light source for outputting a pump lightwave having a wavelength of 2×(?1?1+?2?1)?1; a optical coupler for coupling and outputting the pump lightwave and the signal lightwave; and an optical fiber having a length of 450 m or less, the zero-dispersion wavelength thereof being in the wide wavelength band, the dispersion slope thereof at the zero-dispersion wavelength being +0.01 ps/nm2/km or more and +0.045 ps/nm2/km or less, wherein the optical fiber allows propagation of the signal lightwave and the pump lightwave output from the optical coupler, and generates an idler lightwave by means of the nonlinear optical phenomenon that occurs during such propagation.

Abstract: A guiding nonlinearity cell. The novel nonlinearity cell includes a nonlinear medium and a waveguide adapted to guide input electromagnetic energy through the nonlinear medium. In an illustrative embodiment, the cell includes a thin layer of a liquid or solid nonlinear medium disposed between two parallel plates adapted to guide energy through the length of the medium by total internal reflection. The plates can be made from a material having a refractive index less than a refractive index of the medium to provide total internal reflection within the liquid, or they can be made from a material matching the refractive index of the medium such that outer walls of the plates provide total internal reflection, allowing energy to leak into the plates.

Abstract: An optical fiber reel storing a plurality of optical fibers having an annular frame; a first reel portion provided around an radially outer peripheral surface of the annular frame and receiving at least one of the plurality of optical fibers wound up around the radially outer peripheral surface; and, a second reel portion provided radially inside the annular frame and housing at least one of the plurality of optical fiber therein.

Abstract: Systems and methods for manipulating light with high index contrast waveguides clad with crystalline substances having that exhibit large nonlinear electro-optic constants ?2 and ?3. Waveguides fabricated on SOI wafers and clad with crystalline materials such as barium titanate are described. Embodiments of waveguides having slots, electrical contacts, and input waveguide couplers are discussed. Waveguides having closed loop structures (such as rings and ovals) as well as linear or serpentine waveguides, are described. Optical signal processing methods, such as optical rectification and optical modulation, are disclosed.

Abstract: A compound for spacing nonlinear optical chromophores of the Formula I and the commercially acceptable salts, solvates and hydrates thereof, wherein R1, R2, R3, R4, W, X, Y, Z, Q1, Q2, Q4 and L have the definitions provided herein.

Abstract: A photonic band gap fiber and method of making thereof is provided. The fiber is made of a germanate glass comprising at least 30 mol % of a germanium oxide and has a longitudinal central opening, a microstructured region having a plurality of longitudinal surrounding openings, and a jacket. The air fill fraction of the microstructured region is at least about 90%. The fiber may be made by drawing a preform into a fiber, while applying gas pressure to the microstructured region. The air fill fraction of the microstructured region is changed during the drawing.

Abstract: An apparatus has a waveguide that includes a multiferroic medium. A controller is configured to apply a mechanical strain or a control electric or magnetic field to the multiferroic medium. The multiferroic medium has a dielectric permittivity or magnetic permeability that is responsive to the strain or the control field.

Abstract: An optical device is provided having a solid state nonlinear material with a nanostructured extent, in at least one dimension, that is less than about 10 nm or that is at a temperature of less than about 77 K. An electronic band gap, EGap, of the material is at least about twice as large as an energy of a photon with a wavelength, ?, equal to an operational wavelength of the device. The material is characterized by a switching figure of merit, ?, having a value that is at least about 2?. A dielectric structure is around at least one dimension of the nonlinear material in a geometric arrangement having a characteristic photonic band gap that at least partially overlaps the electronic band gap of the material. At least one waveguide is disposed at the dielectric structure in sufficient proximity with the material for coupling light to the material.

Abstract: A radiation source or detector including a nested waveguide structure is provided. A smaller waveguide provides wave guiding for radiation of shorter wavelength. The smaller waveguide is embedded within a larger waveguide that provides wave guiding for radiation of longer wavelength. Wavelength conversion between the shorter wavelength and the longer wavelength can be realized through a nonlinear process.

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: An optical fiber includes a cladding, a first core, and a second core. At least one of the first core and the second core is hollow and is substantially surrounded by the cladding. At least a portion of the first core is generally parallel to and spaced from at least a portion of the second core. The optical fiber includes a defect substantially surrounded by the cladding, the defect increasing a coupling coefficient between the first core and the second core.

Abstract: An all-fiber optical pulse compression arrangement comprises a concatenated arrangement of a section of input fiber (e.g., a single mode fiber), a graded-index (GRIN) fiber lens and a section of pulse-compressing fiber (e.g., LMA fiber). The GRIN fiber lens is used to provide mode matching between the input fiber (supporting the propagation of chirped optical pulses) and the pulse-compressing fiber, with efficient pulse compression occurring along the length of the LMA fiber. The dispersion and length of the LMA fiber section are selected to provide the desired degree of pulse compression; for example, capable of reconstituting a femtosecond pulse as is used in supercontinuum generation systems.

Abstract: Systems and methods for compensating for nonlinear phase shift accumulation in an optical ring resonator. An example method includes sending a first beam in a clockwise direction around the optical ring resonator and sending a second beam in a counterclockwise direction around the optical ring resonator. Then, nonlinear phase shift accumulation of the first and second beams is compensated for within the optical ring resonator. Compensating includes creating a negative Kerr effect phase shift for each beam based on an estimate of accumulated positive Kerr effect.

Abstract: An all-optical logic gates comprises a nonlinear element such as an optical resonator configured to receive optical input signals, at least one of which is amplitude-modulated to include data. The nonlinear element is configured in relation to the carrier frequency of the optical input signals to perform a logic operation based on the resonant frequency of the nonlinear element in relation to the carrier frequency. Based on the optical input signals, the nonlinear element generates an optical output signal having a binary logic level. A combining medium can be used to combine the optical input signals for discrimination by the nonlinear element to generate the optical output signal. Various embodiments include all-optical AND, NOT, NAND, NOR, OR, XOR, and XNOR gates and memory latch.

Abstract: An all-fiber supercontinuum source is formed as a hybrid combination of a first section of continuum-generating fiber (such as, for example, highly-nonlinear fiber (HNLF)) spliced to a second section of continuum-extending fiber (such as, for example, photonic crystal fiber (PCF)). The second section of fiber is selected to exhibit an anomalous dispersion value in the region of the short wavelength edge of the continuum generated by the first section of fiber. A femtosecond pulse laser source may be used to supply input pulses to the section of HNLF, and the section of PCF is spliced to the termination of the section of HNLF. A section of single mode fiber (SMF) is preferably inserted between the output of the laser source and the HNLF to compress the femtosecond pulses prior to entering the HNLF.

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: 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: Frequency standards based on mode-locked fiber lasers, fiber amplifiers and fiber-based ultra-broad bandwidth light sources, and applications of the same.

Abstract: In a blue extended super continuum light source, when pulses of partly coherent monochromatic “pump” radiation of essentially constant amplitude are propagating through a microstructure fiber medium within a region of anomalous dispersion of the medium, then, provided the medium has a finite nonlinear coefficient of the index of refraction, the pump pulse is subject to a modulation instability. This results in formation of a train of narrow pulses with Tera Hertz repetition rate. Phase match between red shifted Raman solitons generated by the pump pulse and energy shed by the pump pulse at all frequencies with a group velocity below the pump pulse group velocity may lead to the formation of Cherenkov radiation. The solitons may seed Cherenkov radiation at different wavelengths depending on the actual fiber parameters. This allows extension of generated super continuum light beyond the four wave mixing limit when applying picosecond or nanosecond pump pulses.

Abstract: Disclosed are various devices and methods employing photonic crystals to facilitate spatial separation of frequency components of a beam. In one embodiment, an apparatus is provided that includes a preconditioning waveguide facilitating a predefined amount of diffraction of a beam comprising a plurality of wavelengths. A photonic crystal is optically coupled to an output of the preconditioning waveguide. The photonic crystal is configured to spatially separate a plurality of frequency components of the beam.

Abstract: The microstructured optical fibre comprises a core (4) surrounded by a sheath (1) comprising a base material having a refraction index (ni) and a plurality of at least two different types of inclusion: a first type of inclusion (2) having a refraction index n2 (n2>n1), and a second type of inclusion (3) having a refraction index n3 (n3<n1). The inclusions (2, 3) are arranged and dimensioned in such a way as to ensure guidance, by total internal reflection (RTI), of a fundamental mode of the light, centred on a wavelength ?RTI, and of a fundamental mode of the light in the first photonic forbidden band (BG1), centred on a wavelength ?BG1, which is different to that ?RTI of the fundamental mode guided by total internal reflection (RTI).

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: Techniques for generating terahertz (THz) radiation are provided in which each nonlinear crystal in an array of such crystals is coupled to one or more corresponding waveguides such that any THz radiation generated in any single crystal is coupled into that crystal's THz waveguide structure. After the THz radiation is generated in the crystals and coupled into the waveguides, the individual THz signals may be coherently combined to form a single THz signal (non-coherent configurations are provided as well). Crystal-waveguide arrays embodying the techniques can be used to implement efficient, robust, and compact THz sources suitable for applications such as security screening, medical imaging, quality control and process monitoring in manufacturing operations, and package and container inspection.

Abstract: Regarding an optical pulse reshaping device of CPF type, there are subjects to reduce the number of stages by enhancing a compression efficiency as extremely higher for one stage of the CPF with maintaining a quality of an output pulse as high, and to be able to improve a degree of multiplexing by obtaining an output pulse having a Gaussian function for both of a time waveform therefor and a frequency waveform therefor. By using a normal dispersion HNLF in place of a zero dispersion HNLF, which configures the conventional CPF, it becomes able to overcome the above mentioned subjects. Moreover, it becomes able to reduce the number of fusion splice for a fiber, and to reduce a propagation loss of the CPF, by enhancing the compression efficiency as higher.

Abstract: The present invention relates generally to wavelength conversion devices and laser projection systems incorporating the same. According to one embodiment of the present invention, wavelength conversion devices are provided without limitation of their field of use to laser projection systems. For example, the wavelength conversion device may comprise an axial waveguide portion and a pair of lateral planar waveguide portions confined between a pair of relatively low index cladding layers. The effective index of refraction in the axial waveguide portion of the waveguide region and the effective index of refraction in the lateral planar waveguide portions of the waveguide region are established such that the relatively low intensity laterally distributed parasitic light is characterized by a scattering angle ? that is at least as large as the beam divergence angle of the relatively high intensity light propagating in the axial waveguide portion.

Abstract: A polarizing film is made of multilayer polarizing fibers embedded within a matrix. The fibers are formed with layers of at least a first and a second polymer material. Layers of the first polymer material are disposed between layers of the second polymer material. At least one of the first and second polymer materials is birefringent. In some embodiments the thickness of the layers of at least one of the materials varies across the fiber, and may include layers are selected as quarter-wavelength thickness for light having a wavelength of more than 700 nm.

Abstract: Excitation of a triad artificial photosynthetic reaction center consisting of a porphyrin (P) convalently linked to a fullerene electron acceptor (C60) and a carotenoid secondary donor (C) leads to the formation of a long-lived C+-P-C60? charge-separated state via photoinduced electron transfer. This reaction occurs in a frozen organic glass down to at least 8 K. At 77 K, charge recombination of C*+-P-C60? occurs on the ?s time scale, and yields solely the carotenoid triplet state. In the presence of a small (20 mT) static magnetic field, the lifetime of the charge-separated state is increased by 50%. This is ascribed to the effect of the magnetic field on interconversion of the singlet and triplet biradicals. At zero field, the initially formed singlet biradical state is in equilibrium with the three triplet biradical sublevels, and all four states have comparable populations. Decay to the carotenoid triplet only occurs from the three triplet sublevels.