Abstract: The present invention relates to an arrayed waveguide grating having a reflective input that permits variable coupling to adjust the center wavelength. The present invention has found that by providing an arrayed waveguide grating having one or more precisely positioned input waveguides coupled through a reflective lens assembly, for providing a lateral offset to a signal propagating from the input waveguide to the planar waveguide, and for focusing a reflected input signal at a selected input point of the input planar waveguide, alignment and tuning of an input and assembly can be improved and simplified. Advantageously, variable coupling parameters can be incorporated into the reflective coupling including input position, waveguide taper and planar waveguide length increment to provide relatively simple tuning in an integrated device. Compensation for polarization effects and thermal effects can also be provided in the reflective coupling.

Abstract: An Optical Domain Signal Analyzer, having an optical filter, a dispersive element and a detector is utilized to provide high resolution spectrum analysis over a wide optical bandwidth. The optical domain signal analyzer broadly includes an optical filter for providing wavelength samples of a received optical signal, a dispersive element for receiving the samples and dispersing the samples, and a detector for receiving the dispersed signal and for providing electrical signals representative of the dispersed sample. A preferred embodiment includes a processor for receiving the electrical signal and calculating the characteristics of the spectrum.

Abstract: Interleaver/deinterleaver apparatuses for combining/separating optical channels are described. When operating as a deinterleaver, the interleaver/deinterleaver separates an optical signal (e.g. WDM signal) into subsets of optical signals (e.g. channels). In one embodiment, deinterleaving optical signals separates an optical signal into even and odd International Telecommunications Union (ITU) channels. The interleaver/deinterleavers may include isolator components to route optical signals to and from input/output ports. A variety of reflective elements, e.g. quarter wave mirrors, reflective prisms, etalons, can be used for double passing the signals through a birefringent crystal assembly.

Abstract: Optical filters and their manufacture, as well as the use of the optical filters in optical devices, such as polarizers and mirrors are described. The optical filters typically include a first reflective multilayer film, a second reflective multilayer film, and a lossy element disposed between the first and second reflective multilayer films.

Abstract: A light dispersing device for dispersing a polychromatic input beam into a plurality of narrow-band output beams such that the output beams are directed in a wavelength dependent manner and such that the directions of the output beams are less affected by a change in temperature. The preferred embodiment of the device comprises a diffraction grating mounted to a surface of a prism. The grating and prism have dispersing characteristics that make the output of the device substantially insensitive to a change in temperature. In one embodiment, the device is adapted to reduce the angles between the input beam and the output beams at the grating, and thereby improve throughput efficiency.

Abstract: A method and apparatus for maintaining an alignment of a laser diode with an optical fiber is disclosed. A mounting plate is made of a first material, and mounted on the mounting plate is a first substrate made of a second material. A semiconductor laser, with a light emitting side, is mounted on the first substrate. Separated from the first substrate by a predetermined distance is a second substrate made of a third material, and mounted on the second substrate is an optical fiber. The optical fiber is mounted, such that, the optical fiber is adjacent to and aligned with the light emitting side of the semiconductor laser. The first, second, and third materials making up the mounting plate, the first substrate, and the second substrate respectively, facilitate maintenance of the alignment between the optical fiber and the light emitting side of the semiconductor laser.

Abstract: An optical reduction system with polarization dose sensitive output for use in the photolithographic manufacture of semiconductor devices having variable compensation for reticle retardation before the long conjugate end. The variable compensation component(s) before the reticle provides accurate adjustment of the polarization state at or near the reticle. The variable compensation components can be variable wave plates, layered wave plates, opposing mirrors, a Berek's compensator and/or a Soleil-Babinet compensator. The catadioptric optical reduction system provides a relatively high numerical aperture of 0.7 capable of patterning features smaller than 0.25 microns over a 26 mm×5 mm field. The optical reduction system is thereby well adapted to a step and scan microlithographic exposure tool as used in semiconductor manufacturing. Several other embodiments combine elements of different refracting power to widen the spectral bandwidth which can be achieved.

Abstract: Plane diffraction grating 13 is formed of a material having an appropriate linear expansion coefficient and a variation in the wavelength of the reflected light from concave mirror 14 on account of thermal expansion or shrinkage of members other than plane diffraction grating 13 is cancelled out or reduced by a variation in the wavelength of the reflected light from concave mirror 14 on account of thermal expansion or shrinkage of plane diffraction grating 13. The same principle is used to deal with the effect on the wavelength of the diffracted light that may be caused by changes in the layout of individual members on account of thermal expansion or shrinkage of substrate 10a that fix them.

Abstract: In an image reconstructing apparatus 10 for reconstructing a hologram, when a lid 11 is nearly upright in relation to an apparatus body 12, a light emitted from an illumination light source 15 is projected at a predetermined angle of incidence to a hologram 17a placed on a mount surface 16a of a holder 16 of the apparatus body 12 while the light source 15 is being moved.

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: A new optical sensing device containing fiber Bragg gratings, a scanning bandpass filter, an interferometer and multiple photodetectors is disclosed. The present invention also describes a new system and method for fibre Bragg grating (FBG) sensor interrogation and multiplexing. The new system combines a scanning Fabry-Perot (SFP) bandpass filter used to wavelength-multiplex multiple gratings in a single fiber, and an unbalanced Mach-Zehnder fibre interferometer made with a 3×3 coupler to detect strain-induced wavelength shifts. A passive technique for interferometer drift compensation using non-sensing FBGs is included in the system. A complete prototype system interrogates four gratings in a single fiber at a Nyquist sampling rate up to 10 kHz, with a noise floor measured near 4 n&egr; Hz−1/2 above 0.1 Hz. The inclusion of the interferometer drift compensation technique is shown to make quasi-static measurements feasible.

Abstract: Apparatus for holographic recording of information includes a lens or lens system, referred to here as the “FT lens,” situated in such a way that light from an object beam enters the FT lens after passing through an object, and light leaving the FT lens impinges on a recording medium situated at a Fourier transform plane of the object with respect to the FT lens. Disclosed apparatus includes a phase element effectively juxtaposed with the object, in which the phase element is effective for redistributing object-beam intensity in the Fourier transform plane, and the phase element has a correlation length greater than a maximum pixel side length associated with the object. Disclosed apparatus includes an optical element or optical system, referred to here as a “power optic,” that adds convergence or divergence to the object beam before the object beam enters the FT lens.

Abstract: A stack of two or more birefringent crystals having complimentary properties is arranged to have zero net beam walk-off at off-normal incidence and a finite free-spectral range. In another embodiment, the birefringent crystal materials are selected to provide reduced temperature dependence. The result is an optically and mechanically stable composite birefringent crystal unit. A variety of folded birefringent filters are implemented using the composite birefringent crystal.

Abstract: A diffractive optical element for white light is composed of a plurality of layers of optical materials and has a relief pattern constituting a diffraction grating formed at least at one cementing interface between the two different optical materials. The grating height of the relief pattern constituting the diffraction grating is defined by the following formula: h=&lgr;/|n−n′| where h represents the grating height of the relief pattern constituting the diffraction grating; &lgr; represents the wavelength (here it is assumed that &lgr;≦450 (nm)); n represents the refractive index of the optical material abutting the interface from the object side for light of the wavelength &lgr;; and n′ represents the refractive index of the optical material abutting the interface from the image side for light of the wavelength &lgr;.

Abstract: A reflection type color display device and a reflection type of direct-view color display device are provided. The reflection type color display device includes a spatial light modulator having a collection of pixels and a controllable transmittance per pixel, with a reflection type hologram color filter located on the back side of the modulator. The reflection type of direct-view color display device includes a hologram color filter which has an array of light-collecting holograms. Each of the light-collecting holograms has its own hologram color filter, reflection type hologram, and transmission type spatial light modulator located between the hologram color filter and the reflection type hologram.

Abstract: Methods for connecting two optical fibers having different mode field diameters ((MFD) with low connection loss is proposed. One method comprises steps of preparing the third fiber (Fiber 3), a short length and MFD being smaller than that of the first fiber (Fiber 1) and larger than that of the second (Fiber 2), connecting the Fiber 1 to 3, connecting Fiber 2 to 3, and increasing MFD of Fiber 3 near the part connected or to be connected to Fiber 1, or MFD of Fiber 2 near the part connected or to be connected to Fiber 3 by heating the corresponding part. The other method comprises steps of preparing a short length Fiber 3 having smaller MFD than that of Fiber 1, increasing MFD of Fiber 3 near the part to be connected to Fiber 1 by heating the corresponding part, and then connecting Fiber 1 to 3, and 3 to 2 in that order.

Abstract: An optical module comprising: an optical element flip-chip mounted on a substrate; an optical waveguide formed on the substrate and optically connected to the optical element; and underfill resin filled in between the substrate and the optical element and covering an optical junction between the optical element and the optical waveguide, wherein the underfill resin is of an electrically insulating material and has a refractive index equal to or smaller than a refractive index of a clad portion of the optical waveguide. The optical element can be flip-chip mounted with improved mechanical and electrical mounting reliability and thus satisfactory optical connection can be maintained. Further, it never occurs that light passing through the optical waveguide leaks to the underfill resin in the optical junction between the optical waveguide and the optical element.

Abstract: The present invention concerns methods and devices for creating and printing variable size and variable resolution holographic stereograms and holographic optical elements using computer rendered images of three-dimensional computer models or using computer processed images. The present invention is an apparatus and method for printing one-step, full-color, full-parallax holographic stereograms utilizing a reference beam-steering system that allows a reference beam to expose a holographic recording material from different angles. More particularly, a coherent beam is split into object and reference beams. The object beam passes through an object beam unit in which a rendered image is displayed, while the reference beam passes through the reference beam-steering system. The object and reference beams interfere with each other at an elemental hologram on a holographic recording material.

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: The present invention relates to bi-directional circulators based on interleaver technology, e.g. birefringent crystal interleaver technology, that enables signals containing even number ITU channels to travel in one direction through the device, while signals containing odd number ITU channels travel in the opposite direction. Open and closed three and four port devices are disclosed, as well as several useful implementations of the three port device in combination with other optical components, which result in hybrid uni-directional and bi-directional devices.