Abstract: A microfabrication process for preparing articles in which a precursor article that includes (a) a substrate, (b) a first polymer layer overlying the substrate, (c) a second polymer layer overlying the first polymer layer, (d) a metal hardmask layer overlying the second polymer layer, and (e) a photodefinable layer overlying the metal hardmask layer is subjected to photolithographic imaging, developing, and plasma etching steps to form an article that includes the substrate and portions of the first polymer layer arranged in a pattern corresponding to the pattern of the photomask used for photolithographic imaging.

Abstract: An optical fiber suitable for generation of a supercontinuum spectrum when light pulses of femtosecond (10−15 sec.) duration are launched at a certain wavelength into the fiber. The fiber includes a number of sections of highly non-linear fiber (HNLF) wherein each section exhibits a different dispersion at the wavelength of the launched light pulses. The fiber sections are joined, for example, by fusion splicing the sections in series with one another so that the dispersions of the sections decrease from an input end to an output end of the fiber. In the disclosed embodiment, a low noise, coherent supercontinuum spanning more than one octave is generated at the output end of the fiber when pulses of light of 188 fs duration are launched into the fiber at a repetition rate of 33 MHz and with an energy of three nanojoules per pulse.

Abstract: A technique for achieving quasi phase matching in a photonic band gap structure comprising a first material and a second material is disclosed.

Abstract: An optical communications system comprises, among other things, a laser source; an optical waveguide interconnected to the laser source to carry an optical signal from the source to an optical receiver; an optical receiver interconnected to the optical waveguide for decoding the signal; and a mechanical modulator adapted to substantially continuously mechanically perturb a portion of the optical waveguide so as to reduce Rayleigh backscattering from the optical waveguide.

Abstract: An unidirectional gyrotropic photonic crystal allows electromagnetic wave propagation in a certain direction at a certain frequency and, at the same time, impedes electromagnetic wave propagation in the opposite direction. The electromagnetic wave with impeded propagation, called the “frozen mode”, ideally has zero group velocity and does not transfer the electromagnetic energy. A unidirectional gyrotropic photonic crystal is a periodic composite, incorporating a component displaying Faraday rotation. The property of unidirectionality can be achieved in gyrotropic photonic crystals by proper choices of constituents and their space arrangement. The invention can be used to enhance the capability and performance of microwave, millimeter wave, and submillimeter wave antennas, delay lines, nonlinear and nonreciprocal elements. It can also be used in integrated microwave circuitry.

Abstract: All-optical timing extraction and optical clock recovery for high-speed return-to-zero binary optical data streams using the timing difference between clock and data counter-propagating optical pulses in a non-linear optical waveguide where the first pulse to arrive at the non-linear optical waveguide partially saturates the transmission properties of the waveguide resulting in a change of the transmission properties seen by the lagging pulse. A balanced photo-detector makes delay-dependent comparisons of the clock and data pulses' peak power and generates an error signal used in a phase-locked loop configuration to synchronize the clock to the data stream.

Abstract: An optical threshold device including an optical loop having first and second terminals aid including at least one non-linear optical element and at least one optical attenuator; and an optical coupler able to couple a first portion of an input signal to the first terminal and a second portion of the input signal to the second terminal, wherein the optical loop is able to produce a first return signal at the second terminal and a second return signal at the first terminal, and wherein the optical coupler is able to combine the first and second return signals into an output signal.

Abstract: An optical threshold device including an input, an output, first and second radiation guiding branches, each branch having first and second terminals, at least one of the first and second branches having a non-linear optical element, first and second optical couplers, at least one of the first and second optical couplers having an asymmetric optical coupler, the first optical coupler configured to split an input signal of radiation from the input into a first radiation portion propagating through the first branch and a second radiation portion propagating through the second branch, the second optical coupler configured to combine the first and second radiation portions from the second terminals of the first and second branches, respectively, into an output signal at the output, wherein the non-linear optical element produces a phase shift between the first and second radiation portions and wherein the first and second radiation portions interfere at the second coupler in response to the phase shift.

Abstract: Methods for fabricating a non-linear optical (NLO) film and a NLO film structure produced thereby are provided. The methods include depositing an alignment layer material on at least one surface of a substrate, aligning the molecules of the alignment layer material in a substantially uniaxial direction, and depositing a NLO film on the alignment layer material. The methods may be advantageous in that they tend to produce NLO films having relatively strong NLO properties. The methods may be further advantageous in that they are relatively simple and may be applied to a wide range of organic NLO materials.

Abstract: A nonlinear optical device, comprises a source of input light having a first spectrum and an optical fibre 10 arranged so that in use the light propagates through the fibre 10, the optical fibre 10 comprises a tapered region including a waist 30, the waist 30 having a diameter smaller than 10 microns for a length of more than 20 mm, wherein the propagating light is converted by nonlinear optical processes into output light having a spectrum different from the first spectrum.

Abstract: A short pulse generation system and method of generating a short pulse signal are provided. The system includes a fiber chain having an input for receiving an optical signal having a plurality of optical pulses. The fiber chain is nonlinear with respect to the optical signal and includes a first normal fiber segment having a relatively small chromatic parameter, a first abnormal fiber segment having a relatively large chromatic parameter coupled to an output of the first normal fiber segment, and a second abnormal fiber segment having a relatively small chromatic parameter coupled to an out of the first abnormal fiber segment. The system includes a filter stage coupled to an output of the fiber chain and that has a transparent wavelength selected to regenerate the signal. A short pulse signal is produced when the optical signal is coupled to the input.

Abstract: A photonic logic device, such as an optical matrix (105), may include input ports for receiving photonic signals and output ports for transmitting result signals. A plurality of optical elements (130-183) may be configured to implement Boolean functions (210) of information encoded within the received signals to produce the result signals. A photonic logic device may be configured to implement any Boolean function (350) by combining photonic XOR and OR devices (360), or with an automated design process (510-570) based on an evolutionary programming technique (610-680). The photonic logic device may then be manufactured using masking techniques.

Abstract: An optical fiber having an elevated threshold for stimulated Brillouin scattering is provided. The optical fiber includes a core and a cladding surrounding the core with both the core and the cladding designed to guide optical waves through the core while anti-guiding acoustic waves. Moreover, the optical fiber includes other features to alter the mode profile of the acoustic waves and/or to further promote their lateral radiation. For example, the optical fiber can include an irregular coating to alter the mode profile of the acoustic waves. In another example, the optical fiber can include a quarter wave layer surrounding the cladding to promote the lateral radiation of the acoustic waves. In order to further alter the mode profile of the acoustic waves, the cladding can also have a lateral thickness that varies irregularly in a lengthwise direction.

Abstract: The invention provides for novel substituted-polyaryl chromophoric compounds which desirably comprise a single diazo group, and optimally include a plurality of diazo groups. Preferably the chromophores exhibit optical nonlinear second-order properties and have unique absorption maximum and other chromophoric properties that make them useful for, among other things, muitifonctional optical switches or waveguides.

Abstract: An optical method for quantum computing that makes use of nonlocal effects to construct the quantum gates themselves. A nonlocal interaction in which pairs of atoms interchange two photons produces a large nonlinear phase shift. These nonlinear phase shifts are used to construct quantum logic gates, such as a Controlled-NOT.

Abstract: A method introduces variable time offsets into a stream of optical pulses. The method includes receiving a plurality of coherent optical pulses, receiving a plurality of control signals, and forming a coherent pulse array (CPA) from each pulse in response to one of the received control signals. Temporal spacings between pulses of each CPA are responsive to the associated one of the received control signals. For optical control signals, response times can be very short. The method further includes transmitting each pulse through a dispersive optical medium. The act of transmitting makes pulses of each CPA overlap to form an interference pattern.

Abstract: Passive optical channel equalizer apparatus includes first and second waveguides arranged to form a Mach-Zehnder interferometer. A non-linear optical medium section is formed in one of the waveguides and is capable of self-phase modulating each channel of an N-channel multiplexed lightwave to produce an output lightwave having improved channel power uniformity.

Abstract: An optical fiber, capable of generating by means of nonlinear phenomena, white light in adequately broadened wavelength bands at both sides of a pumping optical pulse that is input, and stabilizing the polarized conditions. The fiber is formed by covering a core with a first cladding, and covering the first cladding with a second cladding, where the second cladding has a refractive index greater than that of the first cladding, but lower than that of the core. Stress-applying parts are provided inside the second cladding so as to sandwich the core from both sides to form a polarization-maintaining optical fiber. The shortest distance between the stress-applying parts is made 2.3 times or more the mode field diameter for the wavelength of the pumping optical pulse.

Abstract: A gap soliton can be controlled by introducing a perturbation into a waveguide structure that includes an otherwise essentially periodic variation of its refractive index. In one embodiment of our invention, by controlling the amplitude, phase and/or average value of the refractive index of a first perturbation, and by maintaining the speed of the soliton below a certain critical speed, we have found that the soliton will transfer its energy to the modes of the perturbation. When the soliton transfers essentially all of its energy in this way, we refer to the soliton as being trapped or captured by the perturbation. Surprisingly, the soliton can be trapped without loss of a significant amount of its energy. In an alternative embodiment, when the speed of the soliton exceeds the critical speed, a second perturbation is introduced into the waveguide structure to reduce the speed of the soliton, thereby enabling its capture by the first perturbation.

Abstract: The system includes a fixed wavelength laser and a tunable wavelength laser as inputs. Respective input optical fibers receive the inputs and transmit them to a first position proximate a location on a surface to be interrogated. Respective fiber coupling optics deliver the inputs to the interrogated location on the surface. The inputs are alignable so that their surface locations of optical illumination overlap on the interrogated location. Output fiber coupling optics receives a reflected output resulting from a three-wave mixing process occurring at the interrogated location. An output optical fiber receives an output of the output fiber coupling optics and transmits the output to a desired position from the interrogated location.

Abstract: Disclosed herein is a device including first and second optical couplers and a loop optical path. The first optical coupler includes first and second optical paths directionally coupled to each other. The loop optical path includes an optical fiber as a nonlinear optical medium, and connects the first and second optical paths. The second optical coupler includes a third optical path directionally coupled to the loop optical path. The optical fiber has an enough large nonlinear coefficient. The wording of “enough large” means that the nonlinear coefficient is large enough to reduce the length of the optical fiber to such an extent that the optical fiber has a polarization maintaining ability. By using such an optical fiber having an enough large nonlinear coefficient, a relatively short optical fiber can be used as the nonlinear optical medium.

Abstract: The present invention provides a family of novel polymeric devices including an optical laser and optical amplifier, as well as novel methods and materials for their manufacture. The devices of the invention preferably each comprise optical nonlinear second-order polymers (including polymer blends) which exhibit electroluminescence. The devices can be present in a single layer (e.g., either singly, or in an array including a side-by-side arrangement), and optionally comprise a plurality of layers, such as at least two layers, preferably which are stacked (e.g., either a stack of single devices, or a stack of arrayed devices). The devices of the invention optionally can be fabricated attached to other devices (optical or non-optical) or elements of devices (e.g., electrodes and the like).

Abstract: An enhanced entropy camera provides enhanced image quality by utilizing a custom analog-to-digital conversion function. The analog-to-digital conversion occurs according to a custom non-linear quantization function that provides enhanced entropy in the digitized image, yet avoids the harsh artifacts that tend to arise in images quantized according to a maximum entropy function. A plurality of custom non-linear functions are made available for selection depending upon imaging conditions, such as light intensity, pigmentation of the retina, or the part of the retina being imaged. Each of the plural non-linear quantization function comprises a distinct non-linear look up table for each of plural bands (e.g., red, green, and blue color channels).

Abstract: The invention provides a multifunctional optical switch that among other things, optionally can function as an optical wavelength division multiplexer, wavelength division demultiplexer, add-drop multiplexer and/or inter-connect device. The invention further provides novel methods of manufacturing the optical switch. The optical switch can comprise a single layer, and optimally includes of a plurality of layers which each comprise an optical nonlinear second-order polymer. The optical nonlinear second-order polymer present in each layer differs from that present in any other layer in terms of its absorption maximum (i.e., due to possession of different chromophores).

Abstract: A tuned optical resonator having a substrate and an input waveguide and an optical resonator waveguide formed on the substrate. The optical resonator waveguide has a resonant frequency, exhibits a first index of refraction, temporarily exhibits a second index of refraction responsive to application of laser energy, and temporarily resonates at the resonant frequency while the laser energy is being applied.

Abstract: The invention relates to a modulation controlling circuit for supplying a modulating signal to an external modulator that outputs a modulated optical signal, while setting a proper operating point in the external modulator. The external modulator that operates in cooperation with the modulation controlling circuit of the invention enables high-quality modulation at a wide bit rate range. Therefore, in an optical transmission system or a measuring instrument to which the invention is applied, the characteristics and the performance are improved and the operation is made stable without loss of advantages of the external modulator.

Abstract: A broadband ASE light source is provided which comprises an amplifying optical fiber doped with rare earth; a pumping light source and an output port both which are connected to one end of the amplifying optical fiber via a multiplexer; and a reflecting or circulating member which is connected to the other end of the amplifying optical fiber, whereby the amplifying optical fiber emits ASE light containing a first and second wavelength bands through the port. Particularly, a second pumping light source may be connected to the other end of the amplifying optical fiber via another multiplexer to widen the wavelength band to longer wavelength side. Further, using the amplifying Er-doped optical fiber with the pumping light sources having wavelength of a 980 nm band, the ASE light source can emit a flattened broadband of 1530 to 1610 nm, combining the two wavelength bands of 1530 to 1570 mn and 1570 to 1610 nm.

Abstract: A method for producing an optical waveguide part includes the steps of preparing a ferroelectric single crystalline substrate having a polarization-axis substantially parallel to a main surface thereof and having a given ferroelectric domain-inverted pattern, and epitaxially growing a ferroelectric single crystalline film on the ferroelectric single crystalline substrate. The ferroelectric domain-inverted pattern is thereby transcribed from the substrate into the ferroelectric single crystalline film to form a ferroelectric domain-inverted structure therein.

Abstract: A microstructured optical waveguide that supports the propagation of an optical signal of a desired wavelength is described. The optical waveguide includes a core region formed from an optically nonlinear material having a &ggr; of at least about 2.5×10−19 m2/W at 1260 nm. The optical waveguide also includes a cladding region surrounding the core region, the cladding region including a bulk material and a lattice of columns located in the bulk material, the lattice of columns having a pitch, and each column having a cross-sectional area. The pitch of the lattice and the areas of the columns are selected such that the dispersion of the optical signal at the desired wavelength is within the range of about −70 ps/nm-km to about 70 ps/nm-km.

Abstract: The invention provides organic optical waveguide devices which employ perfluoropolymeric materials having low optical loss and low birefringence. An optical element has a substrate; a patterned, light transmissive perfluoropolymer core composition; and a light reflecting cladding composition on the pattern of the core. Writing of high-efficiency waveguide gratings is also disclosed.

Abstract: An optical device includes a waveguide bounded by a region containing a photonic band gap the properties of which determined the transfer characteristic of the waveguide. Such a device may serve as a component of, for example a wavelength division multiplexer, a monochromatic laser or a chemical sensor. It may serve as an optical bus for an electronic component such as a microprocessor. These devices are particularly suitable for incorporation in optical and opto-electronic integrated circuits as they permit the fabrication of waveguides having right-angle bends with a radius of the order of 2 &mgr;m.

Abstract: A variable optical attenuator having a multiple quantum well structure (MQWS), a feedback system that provides a feedback signal, and a current control that utilizes the feedback signal to regulate the attenuation of the MQWS. In one embodiment, the MQWS is part of a photo intrinsic diode, and in another embodiment it is part of a self-electro-optic effect device (SEED). Preferably, there are a plurality of MQWSs, which may be arranged in a serial stack or may be arranged in a plane parallel to the MQWS layers, with light passed from one MQWS to the next via prisms. Preferably, the beam is separated into component wavelengths by a demultiplexer, each wavelength is attenuated by one or more MQWSs designed to attenuate that wavelength, and the beam is then recombined with an optical multiplexer. In another embodiment, the attenuator is combined with an erbium-doped fiber amplifier (EDFA) to provide an amplifier having an essentially flat gain as a function of wavelength.

Abstract: The figure-8 optical fiber pulse laser according to the present invention produces stable femto-second optical pulses using DI-NOLM. The optical amplifier is not included in DI-NOLM, instead, it is located at the unidirectional linear loop part. And the noise due to the bidirectional gain difference of the optical amplifier is reduced. Two optical fibers of different dispersion values are used at DI-NOLM. Therefore, the present invention provides a figure-8 optical fiber pulse laser using DI-NOLM improving the switching characteristic. Especially, the stable femto-second laser according to the present invention is applicable for the many applications such as high-speed reaction measurements, laser treatments, and medical lasers.

Abstract: The methods and apparatus according to the invention equalize the power of at least one frequency in a multi-wavelength optical signal, or limit the power contained in a single or multi-frequency signal. More particularly, the optical power equalizer according to the invention is a filter with separably variable wavelength dependent transmission coefficients, wherein each coefficient decreases with increasing power for each respective wavelength coupled to the equalizer. Thus, the highest power wavelength output from an EDFA will be filtered more than the lower power wavelengths, making the output power from the EDFA more evenly distributed among the wavelengths. Such an equalizer can be placed downstream from each EDFA without destabilizing the optical network so that no changes need to be made to the EDFA or to the other components in the system.

Abstract: An apparatus and method for transmitting an optical signal. The invention is directed to a transmission line having first (16) and second (18) spans of single mode fiber. The fiber of the first span has a negative dispersion with an absolute value of between about 2.5 ps/nm/km and 10 ps/nm/km at the operating wavelength. The second span (18) is connected to the first span (16) and has a positive dispersion at the operating wavelength. The positive dispersion of the second span compensates for the negative dispersion of the first span such that the cumulative dispersion across the first and second spans is approximately zero. The increased dispersion of the first span coincides with characteristics to lower non-linear effects, permits a longer length of the second span, and helps lower attenuation in the transmission line.

Abstract: An optical waveguide element includes a three-dimensional optical waveguide of a bulky non-linear optical crystal, a substrate, and a joining layer made of an amorphous material. The substrate is joined to the optical waveguide via the joining layer.

Abstract: The invention relates to a method of reducing the intensity distortion induced by cross phase modulation in a wavelength division multiplexed optical fiber transmission system comprising a transmission line made up of a plurality of optical fiber segments with repeaters interposed between successive optical fiber segments, the transmission system having N different wavelength channels, where N is an integer greater than unity. In each repeater interconnecting first and second consecutive fiber segments, a time offset is introduced between the channels in such a manner that compared with the inlet of the first optical segment, the (n+1)th and the nth channels are offset by &tgr;n at the inlet to the second fiber segment, where n is an integer less than or equal to N, where &tgr;n is selected to be greater than zero and less than a value that eliminates correlation between the intensity distortion contributions of each fiber segment.

Abstract: The present invention relates to nonlinear optical (NLO) materials, compositions thereof and NLO devices using polymeric matrices supporting a second order NLO material defined by the formula ED—B—EW  (I) where ED is an electron donating moiety, B is a bridging moiety, and EW is the electron withdrawing moiety (terminal acceptor group) defined by formula II, where C1 is a carbon atom linked through a double bond to a cyclic or an acylic carbon atom in the bridging moiety, and A1, A2, A3 or A4are the same or different from one another, each of which is an electron withdrawing group such as CN, COR, COOR, COOH or CH═C(R)2 where R is a C1-6 alkyl.

Abstract: One or more optical fiber elements each constituted by a coated glass fiber are fed to an over-coating device and an over-coating is applied to the optical fiber elements in a lump, the feeding speed of the optical fiber elements to the over-coating device is made larger than the take-up speed of the over-coated optical fiber onto a take-up reel so as to give longitudinal compression strain to the glass fibers of the over-coated optical fiber. The glass fiber has compression strain of not less than 0.03% to less than 0. 10% in a longitudinal direction thereof at room temperature.

Abstract: A compact apparatus and a method for generating wavelength-tunable short optical pulses, which apparatus and method can change the wavelength of generated pulses without adjustment of an optical system and enable generation of ideal femtosecond soliton pulses. The apparatus includes a short-optical-pulse source, an optical characteristic regulation unit for regulating characteristics of light output from the short-optical-pulse source, and an optical fiber for receiving input pulses from the optical characteristic regulation unit and for changing the wavelength of output pulses linearly. Short optical pulses are input to the optical fiber, so that new soliton pulses are generated in the optical fiber due to its nonlinear effect. Further, the nonlinear effect enables the wavelength of the soliton pulses to shift linearly in accordance with the intensity of input light.

Abstract: This invention relates to fabrication techniques for the creation of new optical elements, an asymmetric (non-reciprocal) diffraction grating and a passive nonlinear optical (visible, microwave, etc.) isolator (diode). It may have potential applications in the field of optical detection (spectrometers) and communications (circulators, wavelength division multiplexing circuits, etc.), etc. One of applications of this proposal is the significant reduction of the noise level in optical communication systems or any other optical systems using laser sources. Another potential interest of these diodes is the fabrication of integrated laser gyroscopes for applications in aviation, etc.

Abstract: The invention discloses an illuminating device (1) having a laser (3) that emits a light beam (7), which is directed onto a microstructured optical element (13) that spectrally broadens the light from the laser. The laser (3) and the microstructured optical element (13) are arranged within the casing.

Abstract: An optical waveguide element has plural spherical bodies arranged in straight or curve with diameters of not more than 100 &mgr;m made of transparent uniform glass. The optical waveguide element may have plural spherical bodies arranged in straight or curve as are viewed from their ends with diameters of not more than 100 &mgr;m made of transparent uniform glass.

Abstract: Techniques for compensating for PMD in multiple WDM channels by processing all WDM channels in the same manner without demultpliexing the channels. A feedback control is provided to decrease the worst-case power penalty and the channel fading probability by optimizing over the entire group of WDM channels.

Abstract: A process shifts wavelengths of optical pulses. The process includes transmitting an incoming optical pulse through a nonlinear optical material, splitting the transmitted pulse into a plurality of mutually coherent optical pulses, and recombining the mutually coherent pulses with temporal delays. The recombined pulses produce a temporal interference pattern. The pattern has a peak whose wavelength is shifted with respect to the wavelength of the incoming optical pulse.

Abstract: An optical device having a waveguide that is formed in a photonic crystal and is provided with a special function utilizing a property specific to the photonic crystal is obtained. The waveguide device includes a waveguide formed in the photonic crystal having a periodic structure formed of at least two kinds of optical mediums. The waveguide is configured not to satisfy arrangement of the periodic structure so as to pass the light of a frequency in a photonic band gap range of the photonic crystal. At a prescribed portion of the waveguide, an optical non-linear medium having linear response as well as quadratic or higher-order non-linear response to the incoming energy of the photoelectric field is provided.

Abstract: An optical modulator includes a dielectric waveguide for receiving an optical beam and coupling energy of the optical beam into the waveguide. At least one Stark material is provided in the waveguide. A bias circuit generates a bias signal to produce an electrical field across the Stark material to shift at least one of the Stark absorption frequencies towards the frequency of the optical beam. A circuit for producing a time varying electric field across the Stark material modulates the optical beam. At least a portion of the bias field can be generated by an alternating bias signal, such as a square wave. A method of modulating optical signals includes the steps of providing a dielectric waveguide for receiving an optical beam and coupling energy of the optical beam into the waveguide, the waveguide having at least one Stark material disposed therein, and varying an electric field imposed across the Stark material.

Abstract: The disclosed coated optical fiber includes a core surrounded by a cladding. At least a segment of the fiber is coated with a photopolymerizable coating composition. The photopolymerizable coating composition is a mixture of at least about 60% of a first polyurethane acrylate coating having a Young's modulus of at least about 400 MPa and about 5-40% of a second polyurethane coating having a Young's modulus of no more than about 50 MPa. The invention further includes a method of making the coated optical fiber. The method includes the steps of blending the photopolymerizable coating composition as recited above and splicing an end section of a first optical fiber having a core and a cladding to an end section of a second optical fiber having a core and a cladding, thereby forming a resultant optical fiber.

Abstract: A photonic switch may be formed using one of a selected group of non-linear optical materials. Each of the materials within this group has a refractive index that demonstrates a substantial peak as a function of wavelength. The photonic switch includes a positive gain, and thus acts as a photonic transistor. In addition, a photonic switch is formed so that a gate signal is applied in a direction that is substantially perpendicular to the direction of the input signal so that there is no effective contamination of the input signal by the gate signal affecting the output signal.

Abstract: A method and apparatus is provided for managing dispersion in a WDM optical transmission system so that transmission performance is improved. The usable optical bandwidth of the transmission system is divided into sub-bands that individually undergo dispersion compensation before being re-combined. Accordingly, in comparison to known dispersion mapping techniques, more WDM data channels reside near a wavelength corresponding to the average zero dispersion wavelength.