Abstract: An optical spectrum analyzer (10), receiving a multi-channel optical signal (12). The optical signal (12) is passed through an optical isolator (14) and a fiber coupler (16) to a tunable optical filter. The tunable optical filter comprises one or more fiber Bragg gratings (18) inscribed in a length of optical fiber. The optical fiber is mounted on a means operable to apply a variable strain to the fiber, to they tune the peak wavelength of the Bragg grating (18) over a desired wavelength range, the tunable optical filter thereby reflecting each channel of the input signal (12) in turn. The detector (20) therefore detects a signal only if the input signal (12) contains wavelengths corresponding to the reflection wavelength of a grating (18).

Abstract: The invention relates to a method for preparing a conductive electrode comprising applying a precursor for electrocatalytic or protective coatings on a conductive electrode substrate, irradiating the conductive electrode substrate and the precursor with near infrared (NIR) radiation to form an electrocatalytic or protective coating on the electrode substrate. The invention also relates to an electrode substrate or electrode obtainable by the method, and the use thereof.

Abstract: A fiber optic grating sensor (10) comprising an optical fiber (12) in which a grating portion (14) is provided, the refractive index (16) of the fiber (12) varying periodically along the grating portion (14). The periodic variation of the refractive index (16) has an amplitude envelope which includes, in this example, two regions (24) in which the amplitude of the envelope is substantially reduced, and in this example is substantially nulled. The null regions (24) give the grating portion a spectral profile (20) within which there are, in this example two pass bands (18).

Abstract: Method of removing dents from sheet-metal parts, in particular from lacquered parts of an automobile body, wherein the metal part (3) in the region of a dent (B) is warmed locally in a substantially non-contact manner, in such a way that a mechanical tension gradient produced by the local warming causes the dent to spring back so as to restore the original shape of the metal part.

Abstract: A dual wavelength optical fiber distributed feedback laser comprises a pump laser coupled to a birefringent fiber in which a first grating device (two co-located single phase-shift fiber Bragg gratings (FBGs)) is provided. The grating device gives the laser two potential lasing modes in each of two orthogonal polarization states. A polarization mode coupling FBG selects two orthogonally polarized modes on which the laser oscillates. In a photonic data carrying signal source, the laser is coupled to a polarization dependent, optical modulator operable to apply a modulation, at a data signal frequency, to one polarization mode of the laser output. In an optical waveguide based electronic signal transmission system the modulated and un-modulated polarization modes output from the source are transmitted across a fiber transmission line to a polarizing optical fiber in which the two modes heterodyne to generate an electronic carrier signal in the optical domain.

Abstract: An optical selector for an asynchronous transfer mode (ATM) optical network, the said selector being capable of selecting ATM cells of bits having a frequency of arrival f less than or equal to a predetermined frequency (PCR), the said optical selector comprising: an input having a first device capable of blocking the entry of bits; an output having a second device capable of permitting the outflow of bits; an ATM cell recognition unit constructed in such a way that it recognizes the headers of ATM cells and connected to the said input and to the said output for the transit of bits from the said input to the said output; and an optical decision unit connected operationally to the said first device, to the said second device and the said ATM cell recognition unit.

Abstract: In the present invention an optical waveguide grating sensing device for a dual-parameter optical waveguide grating sensor includes a first optical waveguide grating of a first resonant wavelength provided in a first section of an optical waveguide and a second optical waveguide grating of a second resonant wavelength provided in a second of an optical wavelguide. The first and second gratings have different coefficients of rate of change of wavelength as a function of temperature and have substantially the same coefficient of rate of change of wavelength as a function of stain.

Abstract: A regenerated optical waveguide is fabricated by hydrogenating an optical waveguide (12) and exposing a grating section (28) to a UV laser beam interference fringe pattern (14) to form a Type I grating. The grating section (28) is exposed for a second period to erase the Type I grating, and then a third period to cause a regenerated optical waveguide grating to form. The resonant wavelength increases during the third period from being substantially the same as the final wavelength of the Type I grating.

Abstract: An optical pulse transmission line portion 10, having dispersion slope compensation, comprising an optical waveguide 12 (length L1, dispersion parameter D1) having a dispersion slope parameter (S1) of a first sign, and dispersion compensation means 14 (length L2, dispersion parameter D2) having a dispersion slope parameter (S2) of the opposite sign.

Abstract: Method and apparatus for coating the surface of an object, especially the surface of a car bumper (1) with a plastic film (2). During and/or after application of the plastic film to the surface, the coating is irradiated with infra-red radiation in order to heat at least parts of the coating and/or optionally residual moisture between the surface and the plastic film (2). This enables slight inequalities of the plastic film to be compensated, the adhesive coating is distributed in a homogeneous manner and the optionally residual moisture is collected in the form of bubbles following infrared radiation. Defects or irregularities in the coating can thus be identified during or shortly afterwards.

Abstract: A method and an apparatus for drying a substance that is being rapidly conveyed in a conveyor apparatus, in particular for drying layers of printing ink on rapidly transported paper, wherein in a drying zone by means of incident electromagnetic radiation a moisture component, in particular a solvent, is separated from the substance to be dried. The separated moisture component is transported away from the drying zone by means of a transport gas current. Efficient and rapid drying of in particular printed newsprint or thermal printing paper is attained at high conveyor velocities.

Abstract: New photosensitive acrylic material compositions for fabrication of holographic recording materials (HRMs) are provided. These compositions are comprised of polymerizable acrylic monomers and light absorbing dyes, and when polymerized they are thermally stable, light sensitive, hard and inert to common chemicals. Methods of fabricating HRMs with symmetric concentration distribution of the dye are also provided.

Abstract: The subject invention pertains to electro-optic devices and, in particular, to an integrated-optic modulator with a linearized transfer curve. In a specific embodiment, an integrated-optic modulator with a linearized transfer curve can be formed in an electro-optic substrate and comprises an input Y-junction, a section of two coupled waveguides, followed by two output waveguide bends. Light from a CW optical source can be launched into the input Y-junction and amplitude modulated by applying an external voltage to the electrodes positioned on the top surface of the substrate. The modulator can be driven in both the uniform and Db configuration. By properly adjusting the length of the sections in the coupler with respect to the coupling length, the linearity of the transfer curve is improved. The subject invention is further concerned with realizing modulators with suppressed nonlinear distortions for analog optical links, for example fiber-optic communication links and cable television systems.

Abstract: The subject invention pertains to electro-optic devices and, in particular, to an integrated-optic modulator with a linearized transfer curve. In a specific embodiment, an integrated-optic modulator with a linearized transfer curve can be formed in an electro-optic substrate and comprises an input Y-junction, a section of two coupled waveguides, followed by two output waveguide bends. Light from a CW optical source can be launched into the input Y-junction and amplitude modulated by applying an external voltage to the electrodes positioned on the top surface of the substrate. The modulator can be driven in both the uniform and .DELTA..beta. configuration. By properly adjusting the length of the sections in the coupler with respect to the coupling length, the linearity of the transfer curve is improved The subject invention is further concerned with realizing modulators with suppressed nonlinear distortions for analog optical links, for example fiber-optic communication links and cable television systems.

Abstract: A non reciprocal optical device for transmitting light in a forward and reverse direction substantially independently of polarization state from a collection of waveguides. The device includes: a first array of spaced apart waveguides having at least a first wave guide and a second waveguide; a second array of spaced apart waveguides including at least a third waveguide; an imaging component for focusing a diverging beam of light disposed between the first array and the second array of waveguides, at least two polarization equalization components for polarization equalization of diverging or converging light, each of the polarization equalization components disposed between a waveguide array and the imaging component; add a plurality of polarization rotation components disposed between each waveguide array. Light from the first waveguide is transmitted to the third waveguide and light from the third waveguide is transmitted to the second waveguide in a polarization independent manner.

Abstract: The subject invention pertains to a method of apodizing interaction in spatially-coupled waveguides capable of implementing any desired interaction-strength profiles, for example, alternating functions. Wavelength filters with various types of spectral response can be synthesized. In a preferred embodiment, a Butterworth-type interaction profile is disclosed which provides a flat-top response with suppressed sidelobes. The method according to the subject invention is based on spatially offsetting a single-mode waveguide with respect to a two-mode waveguide in which the anti-symmetric mode is excited by using a Y-junction mode splitter. The method can easily be implemented in vertically-coupled structures fabricated with the use of conventional fabrication processes. Various embodiments of the method implemented. The subject invention further pertains to the device produced in accordance with the methods of the subject invention.

Abstract: A random wavelength access monochromator incorporates a pair of coaxial off-axis parabolic reflectors configured so that the spherical aberrations introduced by the reflectors cancel each other. Light enters through an entrance slit and impinges upon a first off-axis parabolic reflector that collimates the beam and directs it towards a stationary grating. The grating in turn defracts the light and directs it towards a high speed scanning mirror which reflects the defracted light onto a second off-axis parabolic reflector which in turn focuses the beam to an exit slit. Both off-axis parabolic surfaces share the same axis of revolution and the same collimated beam axis. In order to make the apparatus practical, the beam is folded twice so that the exit point is focused away from the internal path of the beam.

Abstract: Disclosed is an integrated, multi-module luminescence measuring system. The system can selectively conduct lifetime decay or steady-state measurements of light emitted by a sample which receives exitation light. The system includes: a sample chamber which directs monochromatized, focused excitation light from a selected source at a selected sample and directs any resultant emitted light through a monochromator to either a first gated photodetector or a second regular photodetector. Also present is a reference module with a regular photodetector which may selectively receive a portion of the excitation light. A lifetime decay detector module pulses a selected light source and the gated photodetector so that a converter produces digital signals related to output signals from the photodetector, the digital signals representing the integral of the intensity of the emitted light over a selected time.

Abstract: A dual wavelength spectrophotometer produces a relatively small, high power, high duty cycle light spot from a single relatively low power multi-chromatic light source. A Xenon arc lamp light source is focused by an ellipsoidal mirror onto a rotating partially reflective optical chopper. The chopper comprises a wheel having mirrored segments alternately separated by transparent segments. Light reflected by the mirrored segments passes through a first monochromator which produces a first monochromatic light beam. Light transmitted through the transparent segments passes through a second monochromator and emerges as a second monochromatic light beam having a wavelength different from the wavelength of said first monochromatic light beam. The first and second monochromatic light beams are recombined into a single dual wavelength light beam that is reflected through a sample to be analyzed. Reflective front surfaces are employed throughout the system in order to minimize power loss.