Abstract: Various embodiments of the present invention are directed to compact systems for generating polarization-entangled photons. In one embodiment of the present invention, a polarization entangled-photon state source comprises a single transmission layer configured for transmitting electromagnetic radiation. The transmission layer includes a beamsplitter and a down-conversion device, both of which are configured to convert a pump beam into first and second signal beams and first and second idler beams. The transmission layer also includes a mode converter configured to invert electric and magnetic field components of both the first signal beam and the first idler beam, and a combiner configured to receive the first and second signal beams and the first and second idler beams and output the first and second signal beams and the first and second idler beams in an entangled polarization states.

Abstract: Terahertz radiation generation systems and methods are implemented using a variety of methods and devices. According to an example embodiment of the present invention, method for generating terahertz radiation is implemented where the wavelength of an optical pulse is controlled, and where the wavelength is controlled as a function of the group velocity dispersion in a nonlinear crystal. The optical pulse is then directed through consecutively-inverted parallel domains in the nonlinear crystal.

Abstract: A method and apparatus for quantum information processing is disclosed in which logical qubits |0>L and |1>L are respectively encoded by different near orthogonal coherent states |?> and |?>, where <?|?>=0, |?> and |?> being the computational basis states for the qubits, for example, in which logical qubits |0>L and |1>L are respectively encoded by different ones of the vacuum state |0> and a multi-photon optical coherent state |?> which states are the computational basis states for the qubits. This provide an efficient scheme for linear optics quantum processing which is deterministic and for which qubit readout can use homodyne detection which is highly efficient. The invention finds application in quantum computation and quantum communication.

Abstract: A high index difference coupler includes a high index difference waveguide having one or more modes. A plurality of gratings is formed on the high index difference waveguide. The effective index difference between low index regions and high index regions of the waveguide is greater than 0.3.

Abstract: An apparatus and method for generating a wavelength-tunable short pulse that can generate wavelength-tunable short pulsed light in the visible-light wavelength band are provided. When ultrashort pulsed light is introduced into an optical fiber (3), a wavelength-tunable ultrashort soliton pulse is generated by a nonlinear optical effect through the soliton effect and Raman scattering. When the soliton pulse has a short duration and high peak intensity, a third harmonic having one-third of the wavelength of the soliton pulsed light is generated by a third nonlinear optical effect. This third harmonic has a short wavelength in the visible light band.

Abstract: Systems and methods for manipulating light with tunable ferroelectric photonic devices. Devices having tunable properties that exhibit photonic bandgap behavior are fabricated from ferroelectric materials. Apparatus is provided to apply tuning signals to the ferroelectric material using one or more of electric fields, mechanical forces, optical fields, and thermal fields. Control circuitry is provided to generate the control signals needed to apply the tuning signals. Input and output ports are provided to allow input signals to be received and to provide output signals. In some cases, a feedback loop is provided to use a portion of the output signal as a diagnostic signal for control of the operation of the device within an acceptable range. It is expected that ferroelectric photonic devices operating according to principles of the invention will be useful for a wide variety of applications, including optical switching, optical modulation, optical computing, and performing logic optically.

Abstract: The present invention relates to a light source apparatus having a structure for stably supplying broadband pulsed light having a wavelength spectrum with an excellent flatness over a wide band. The light source apparatus employs, as a seed light source, a short-pulsed light source having such an excellent output pulse characteristic that the frequency bandwidth extending until the output pulse drops by 10 dB or 20 dB from a peak is 5 THz or more. The light source apparatus also includes a broadband light producing fiber having an optical characteristic suitable for combining with the short-pulsed light source. The broadband light producing fiber inputs pulsed light from the pulsed light source, and produces the broadband pulsed light by utilizing a nonlinear optical phenomenon. This structure yields broadband pulsed light having such a wavelength spectrum that a region whose power fluctuation is suppressed to 6 dB or less extends over 100 nm or more.

Abstract: A nonlinear fiber having a third-order nonlinear coefficient of at least 30 W?1km?1, and its cladding containing Er or Tm at a portion within 3 ?m from the interface with its core. A wavelength conversion method of making a signal light having a wavelength ?S and an intensity IS and a pump light having a wavelength ?P which is shorter than 2?S and an intensity higher than IS enter a nonlinear fiber 1, and generating a converted light having a wavelength ?C of ?S?P/(2?S??P) and an intensity IC by four wave mixing, wherein Er or Tm is present in the cladding at a portion with a diameter in the nonlinear fiber 1 of at most the mode field diameter, and the converted light is generated by four wave mixing while Er or Tm is excited by an excitation light.

Abstract: A Metal Nanoparticle Photonic Bandgap Device in SOI (NC#97882). The device includes a substrate having a semiconductor layer over an insulator layer; a photonic bandgap structure having at least one period operatively coupled to the substrate, adapted to receive and output amplified light along a predetermined path; a metal nanoparticle structure, operatively coupled to the photonic bandgap structure and the substrate, adapted to receive and amplify light rays and output amplified light.

Abstract: A nonlinear optical device including at least a first nonlinear optical grating is provided. The first grating comprises a plurality of adjacent nonlinear optical (NLO) units. Each NLO unit has a single crystal segment and a polycrystalline segment. The single crystal segment is formed from a single crystal of a nonlinear optical material and has a length adapted to provide a nonlinear optical effect. The polycrystalline segment has a length adapted to compensate for phase mismatch that occurs in the single crystal segment. Including a polycrystalline segment in each NLO unit allows for a type of quasi-phase-matching to be achieved in the first nonlinear optical grating. The first grating may be used to form a variety of nonlinear optical devices, including, for example, frequency doublers, frequency adders, frequency subtractors, amplifiers, parametric oscillators, and optical mixers. Further, the first grating may form the core of a waveguide.

Abstract: A photonic crystal is configured with wavelength converting material to act as a concentrator for electromagnetic energy. The concentrator may also be configured with energy conversion devices to convert the electromagnetic energy into another form of energy.

Abstract: An elongate waveguide for guiding light includes a core having an elongate region of relatively low refractive index; a microstructured region around the core having elongate regions of relatively low refractive index interspersed with elongate regions of relatively high refractive index; and a boundary at the interface between the core and the microstructured region, the boundary including in the transverse cross-section, a region of relatively high refractive index, which is connected to the microstructured region at a plurality of nodes, at least one relatively enlarged region around the boundary (and excluding a boundary having twelve nodes and six enlarged regions substantially at a mid-point between six pairs of relatively more-widely-spaced apart neighboring nodes).

Abstract: The invention relates to an asymmetric optical fiber that includes a core and a functional cladding that surrounds substantially half of the core along at least a portion of the fiber. The asymmetric optical fiber may include substantially parallel electrodes disposed on a face of the optical fiber.

Abstract: Light to be sensed is spreaded across an entry surface of a transmission structure with a laterally varying energy transmission function. For example, the light could be output from a stimulus-wavelength converter, provided through an optical fiber, or it could come from a point-like source or broad area source. Output photons from the transmission structure can be photosensed by photosensing components such as an array, position sensor, or array of position sensors. Wavelength information from the light can be obtained in response to the photosensing component. Spreading can be performed by air, gas, transparent material, or vacuum in a gap, by a region or other part of a lens, or by an optical fiber end surface. If the light comes from more than one source, a propagation component can both spread the light and also keep light from the sources separate.

Abstract: A variety of structures, methods, systems, and configurations can support plasmons for logic.

Abstract: An optical device includes at least two photonic bandgap crystal (PBG) stacks that are each comprised of alternating layers of high and low index materials. A defect region is formed in a cavity region between the at least two photonic bandgap crystal stacks so as to provide the properties needed to reflect light received by the optical device.

Abstract: An optical phase modulator comprising a plurality of non-polarizing waveguides having a layered stack including a core between at least one layer of cladding material, wherein the core is constructed of electro-optic material(s), wherein the layers of cladding materials having lower indices of refraction than the core for guided mode, wherein the layer of cladding material having higher indices of refraction than the core for non-guided mode, a substrate dimensioned and configured to integrate a plurality of optical components, wherein the optical components include a plurality of non-polarizing waveguide(s), a waveguide having a non-polarizing non-modulating region and a non-polarizing modulating region, coupler/splitter(s), electrode(s), a waveguide configuration including a first non-polarizing waveguide, a second polarizing waveguide and a third waveguide, and at least two optical fiber pigtails where one is coupled to a second and third waveguide.

Abstract: A method of measuring polarization mode dispersion (PMD) of an optical fiber, includes estimating PMD when an optical fiber is formed as an optical cable, from a beat length when the optical fiber is wound around a bobbin, and an average coupling length when the optical fiber is formed as the optical cable.

Abstract: The invention relates to in particular to a device for optically regenerating pulses, the device comprising an optical bandpass filter adapted for providing time synchronization and intensity stabilization of dispersion-managed soliton pulses. The device further comprises noise suppression means distinct from the bandpass filter.

Abstract: A frequency-selective light coupler-decoupler device comprising a component of photonic crystal structure in which there is formed a waveguide having at least one longitudinal edge with a small number of rows of periodic elements of the photonic crystal so as to form coupling zones between the waveguide and the outside of the photonic crystal at coupling frequencies that are determined in particular by the width of the waveguide and/or by the spatial period of the photonic crystal elements.

Abstract: An apparatus for inspecting a specimen, such as a semiconductor wafer, is provided. The apparatus comprises a laser energy source, such as a deep ultraviolet (DUV) energy source and an optical fiber arrangement. The optical fiber arrangement comprises a core surrounded by a plurality of optical fibers structures used to frequency broaden energy received from the laser energy source into frequency broadened radiation. The frequency broadened radiation is employed as an illumination source for inspecting the specimen. In one aspect, the apparatus comprises a central core and a plurality of structures generally surrounding the central core, the plurality of fibers surround a hollow core fiber filled with a gas at high pressure, a tapered photonic fiber, and/or a spider web photonic crystalline fiber, configured to receive light energy and produce frequency broadened radiation for inspecting the specimen.

Abstract: Plasmons on a waveguide may deliver energy to photocatalyze a reaction. The waveguide or other energy carrier may be configured to carry electromagnetic energy and generate plasmon energy at one or more locations proximate to the waveguide, where the plasmon energy may react chemically with a medium or interaction material.

Abstract: A photonic band gap fiber and method of making thereof is provided. The fiber is made of a non-silica-based glass 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 40%. 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: A hole-assisted holey fiber is provided. The holey fiber includes a core region; a cladding region around the core region, and a plurality of holes in the cladding region around the core region. The core region has a higher refractive index than that of the cladding region. The holes form an inner hole layer and an outer hole layer, and the inner hole layer has the same number of holes as the number of the holes in the outer hole layer. The outer layer holes are provided in locations in which inner holes are absent when viewed from the center of the core region, and holes defining the same layer have the same diameter. A distance ?1 from a center of the core region to a center of an inner hole and a distance ?2 from the center of the core region to a center of an outer hole satisfy the relationship ?1<?2, and a diameter d1 of an inner hole and a diameter d2 of an outer hole satisfy the relationship d1?d2.

Abstract: The present invention provides a set-reset flip-flop operating in an all-optical manner. In this invention, a set pulse is inputted from the setting port. In doing so, only oscillation in set mode is generated at the multi-mode interference portion in a waveguide. As a result, a non-inverting output Q is obtained from the non-inverting output port. This state is then continued even if the set pulse input goes off. Next, a reset pulse is inputted to the resetting port. In doing so, at the multi-mode interference portion, oscillation of light in the set mode is halted, and oscillation in the reset mode occurs. As a result, it is possible to obtain an inverting output Q-bar from the inverting output port. This state is then continued even if the reset pulse goes off.

Abstract: A photonic-crystal electromagnetic-wave device includes a photonic crystal structure having a periodically changed optical property at least in one direction. The photonic crystal structure includes electromagnetic-wave absorptive portions periodically arranged, each of the absorptive portions having an extinction coefficient larger than that of the other portions of the photonic crystal structure.

Abstract: A method and a system to produce, either in numerical simulations or in experiments, specified amounts of first, second and higher order PMD in a controlled manner, in particular large amounts. Parameters can be adjusted to obtain specific ranges of first, second and higher order PMD, and importance sampling can be used to determine the probability that the resulting PMD events can be obtained in realistic situations. Individual results obtained using specific parameter values can be combined to produce even larger ranges of PMD.

Abstract: A photonic crystal fiber includes a core region for propagating light in a longitudinal direction of the fiber, a cladding region surrounding the core region, the cladding region including micro-structural elements extending in the longitudinal direction. The cladding region further includes at least one stress element having a coefficient of thermal expansion ?T,SAP and extending in the longitudinal direction of the photonic crystal fiber, the stress element(s) being located in a cladding background material having a coefficient of thermal expansion ?T,cladback different from ?T,SAP. The location of the at least one stress element relative to the core region and the micro-structural elements and the coefficients of thermal expansion ?T,SAP and ?T,cladback are adapted to provide a stress induced birefringence in the core region of the photonic crystal fiber. An article includes a photonic crystal fiber, a method of manufacturing and the use of a photonic crystal fiber are furthermore provided.

Abstract: A nonlinear-optic waveguide device has a thin-wire optical waveguide including a core having a cross-sectional area of at most 1 ?m2 and a cladding, the core and the cladding having a refractive index difference of at least 1. A light pulse introduced into the core has a peak power of at least several hundreds W and a pulse duration of at most 10 ps. The thin-wire optical waveguide has a length of about 1 cm. The nonlinear optical device, a mode-locked semiconductor laser, and tunable optical filter are combined into a white pulse light source.

Abstract: A nonlinear optical waveguide may be utilized, together with arrayed waveguide grating demultiplexer/multiplexer and thermo-optic phase shifters, to achieve pulse compression of optical pulses. In some embodiments, a relatively compact pulse compressor can be achieved based on integrated planar lightwave circuit.

Abstract: A photonic crystal may be configured to support a surface state for logic.

Abstract: A photonic crystal may be configured to support a surface state for logic.

Abstract: A photonic crystal may be configured to support a surface state for logic.

Abstract: The present invention presents a method to enhance polarization conversion reflection from an anisotropic thin film. The total reflection effect or the high reflection at the interface of an anisotropic thin film leads to enhanced polarization conversion. Polarization conversion is an interesting phenomenon by which a fraction of p(s)-polarized light incident on an anisotropic thin film may be reflected as s(p)-polarized light.

Abstract: A method and arrangement for stimulated Brillouin scattering (SBS) reduction in optical media that generate SBS are provided. SBS is reduced by providing a plurality of segments of optical medium and providing an optical isolator between adjacent pairs of segments so as to reduce the SBS and thereby improve power throughput. The isolators prevent backward propagation of an SBS signal between the adjacent segments. A wavelength multiplier, a wavelength converter and a multi-wavelength laser source, which include the arrangement, are also provided.

Abstract: An apparatus for accelerating assessment of an optical transmission system using Bit Error Rate (BER) tests calculates Q-factors for at least two different extinction ratios from measured test BER values, and extrapolates to determine a Q-factor for an operational extinction ratio, whereby the operational BER value for the operational extinction ratio can be calculated.

Abstract: Rectangular protruding parts 2 are formed on the surface of one side of a quartz crystal substrate 1; these protruding parts 2 are formed as aggregates of rectangular protruding parts 4 of an even finer pattern. Recessed parts 5 which are lower than the surfaces of the protruding parts 4 are formed between the protruding parts 4; however, the width of these recessed parts 5 is narrow, so that when the protruding parts 4 are viewed on the macroscopic scale, numerous protruding parts 4 are aggregated, and appear to form single protruding parts 2. Such a quartz crystal substrate 1 is clamped between heater blocks from above and below, and the temperature of the quartz crystal substrate is elevated. At the point in time at which this temperature reaches a desired temperature, the substrate 1 is pressed by means of a press. Consequently, stress acts only on the portions corresponding to the protruding parts 4, so that the crystal axis components are inverted only in these portions.

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: Thin films exhibiting second-order nonlinear optical (NLO) properties, as well as materials and methods for producing such films, are provided. The films are formed by depositing, on a substrate, alternate layers of a polyelectrolyte and a low molecular weight chromophore. The chromophore contains an electrophilic group that reacts with a previously deposited polyelectrolyte, and ionizable groups which present absorption sites for the next polyelectrolyte layer. The films find application in, for example, electro-optic modulators and frequency doubling devices.

Abstract: Distributed fiber optic chemical and physical sensors provide a relatively highly uniform response over the length of the fiber by, for example, varying such properties as the core/cladding index of refraction ratio to compensate for the non-linearity in sensitivity due for example to the loss of higher order modes in multi-mode fibers. The variation of the ratio changes the absorption coefficient of the fiber and can be used to compensate for any non-linearity in response. Other techniques for compensation also are disclosed.

Abstract: The invention is directed to apparatus, methods, systems and computer programs which permit a simplification or reduction of the description of a complex digital circuit. This is accomplished by using a completely new system of propositional logic (13B), representing the logic of a logical circuit to be designed as points and vectors in a vector space, simplifying the logic so represented to a simpler form using vector transformations, and designing the circuit using the simpler form. The invention is also directed to apparatus, methods, systems and devices which will implement the vector logic system in optical forms, including free-space optical methods, flat-optical methods, colorimetric methods, and methods using a polarization-based AND-gate.

Abstract: A system and method for producing a multiple optical channel source (MOCS). The method includes producing the SC in a medium using at least one femto-second or pico-second optical input pump pulse; splitting input pump pulse or resultant output SC pulse(s) into a plurality of collinear pulses; applying a time delay ? between the least one of input pump pulse or SC pulses; and producing a MOCS by the spectral interference of the plurality of SC pulses. The system includes a laser producing femto-second or pico-second pump pulses, a medium with a high value of the ?(3) nonlinear response to produce spectrally coherent SC, an optical system for delivery of laser pump pulses into the SC producing medium, an optical system for splitting the input pump pulses or output SC pulses into a plurality of collinear pulses, and a means for applying a time delay ? between the plurality of pump or SC pulses.

Abstract: An optical phase modulator comprising a plurality of polarizing waveguides having a layered stack including a core between at least one layer of cladding material, wherein the core is constructed of electro-optic material(s), wherein the layers of cladding materials having lower indices of refraction than the core for guided mode, wherein the layers of cladding materials having higher indices of refraction than the core for non-guided mode, at least one electrode coupled to at least one waveguide including a modulating polarizing region, at least one waveguide having a non-modulating region and a modulating region, a substrate dimensioned and configured to integrate a plurality of optical components, wherein the optical components include a plurality of polarizing waveguide(s), a waveguide having a non-modulating region and a modulating region, coupler/splitter(s), electrode(s), and a waveguide configuration including a first polarizing waveguide, a second polarizing waveguide and a third polarizing waveguide

Abstract: An optical system comprises an optical fiber with gain producing core with an index of refraction n1, surrounded by at least one cladding with an index of refraction n2, said cladding including at least one index reduced area with an index of refraction n2, such that n1>n2>n2, the core propagating a signal at a spatial fundamental mode at a signal wavelength ?1 and at a power level sufficient to generate optical power at a wavelength ?2, where ?2>?1, and the at least one index reduced area in combination with the core provide has at least one cut-off fundamental spatial mode wavelength ?C, and ?1<?C and ?2>?C.

Abstract: An all optical fiber bit stream reader system for examining the data contents of an optical fiber involving the conversion of a temporal timing signal into a spatially located signal is provided. The invention generally comprises generating and detecting a signal indicating the presence of data, in a manner which is minimally destructive to the data. One embodiment comprises providing a piece of optical fiber that exhibits a nonlinear response through a two photon absorption process and subsequent emission of a photon corresponding to the two photon absorption process. Such a fiber could comprise a conventional doped silica fiber into which an additional dopant has been introduced. Another embodiment involves modifying the index of refraction of the cladding of the optical fiber line. This causes a fraction of the electric field or light pulse guided through the fiber (if present) to be coupled out of the fiber. Thereafter, the pulse can be detected.

Abstract: In general, in one aspect, the invention features an apparatus that includes a photonic crystal fiber configured to guide a mode of electromagnetic radiation at a wavelength, ?, along a waveguide axis. The fiber includes a core extending along the waveguide axis, and a confinement region extending along the waveguide axis and surrounding the core. The confinement region includes alternating layers of a first and a second dielectric material having thicknesses d1 and d2 and different refractive indices n1 and n2, respectively. The thickness of at least one of the alternating layers of the first material differs from thickness d1QW or at least one of the alternating layers of the second material differs from thickness d2QW, where d1QW and d2QW correspond to a quarter-wave condition for the two dielectric materials given by d1QW=?/(4?{square root over (n12?1)}) and d2QW=?/(4?{square root over (n22?1)}), respectively.

Abstract: A polymer phase modulator having a plurality of polarizing waveguides having a layered stack including a core between at least one layer of cladding material, wherein the core is constructed of electro-optic material(s), wherein the layers of cladding materials having lower indices of refraction than the core for guided mode, wherein the layer of cladding material having higher indices of refraction than the core for non-guided mode, at least one waveguide having a non-modulating polarizing region, a substrate dimensioned and configured to integrate a plurality of optical components, wherein the optical components include a plurality of polarizing waveguide(s) and non-polarizing waveguide(s), a waveguide having a polarizing non-modulating region and a non-polarizing modulating region, coupler/splitter(s), electrode(s), and a waveguide configuration including a first polarizing waveguide, a coupler/splitter including a plurality of splitter ports, a second polarizing waveguide and a third polarizing waveguide.

Abstract: All optical regeneration methods and systems can be realized through an exponential amplifier and a limiting amplifier, which could be two independent devices (one piece of fiber with parametric amplification and a semiconductor optical amplifier operating at saturation state) or one single device (one piece of fiber). The signal quality and the extinction ratio after regeneration are significantly improved compared with the degraded incoming data using a parametric amplifier with the data signal to be regenerated as the pump. The regenerated data has an extinction ratio as high as 14 dB, an extinction ratio enhancement of approximately 5 dB and an approximately 5 dB negative power penalty. This regeneration schemes are format transparent (RZ and NRZ), and provide noise reduction both for bit 1's and bit 0's of the data sequence. The regeneration method and apparatus that just utilizes fibers has the additional capability of ultrafast response speed (several femtoseconds due to the Kerr effect).

Abstract: In an optical communication system in which communication is conducted by transmitting light through a plastic optical fiber with a core diameter in the range from 300 to 600 ?m, the average beam diameter and beam divergence angle expressed in terms of numerical aperture (NA) of the light at the input face of the optical fiber are set less than or equal to 250 ?m, more preferably less than or equal to 200 ?m, and less than or equal to 0.25, more preferably less than or equal to 0.2 respectively.

Abstract: Nonlinear optical filters and associated methods. In a representative embodiment, a nonlinear optical filter includes a grating and a dye-doped polymer layer coupled to the grating. The dye-doped polymer layer may include ionic self-assembled layers. An associated method includes: providing a nonlinear filter comprising a grating and a dye-doped polymer layer coupled to the grating, directing an input broadband optical wave upon the filter, and backward diffracting the broadband optical wave from the grating as an output narrowband optical wave. The output narrowband optical wave may include a second harmonic beam.