Abstract: A curved wavelet transform and a related image/video compression system are disclosed. The curved wavelet transform (CWT) is carried out by applying one-dimensional (1-D) wavelet filters along curves, rather than along only horizontal and vertical directions. The image/video compression system includes a curve determination unit, a curved wavelet transform unit, a wavelet coefficient quantization unit, a wavelet coefficient coding unit, and a curve coding unit. The quantization and coding of the wavelet coefficients are related to the curves. In one embodiment, recursive wavelet filters are used for inverse wavelet decomposition. The system provides higher compression capability than conventional wavelet-based image compression systems.

Abstract: The invention relates to an optical fiber polarizer comprising an optical fiber with at least a core, a cladding and surrounding medium (or outer cladding) where one or more sections of the optical fiber include periodic/aperiodic (chirped, quasi-periodic) modulation of the dielectric properties of the fiber in the direction of propagation of the light (the longitudinal axis of the fiber). The modulation of the dielectric properties of the fiber is such that it introduces periodic/aperiodic birefringence along the direction of propagation of the light, such a modulation usually but not necessarily being confined to the vicinity of the core region of the fiber. Means are included to attenuate preferentially some of the modes of propagation of the fiber, specifically modes of one principal state of polarization and not the orthogonal state of polarization.

Abstract: A retro-reflective sensor for sensing mechanical, chemical or temperature related information, is disclosed. The sensor is formed of an optical waveguide suitable for use in-situ in a high temperature environment having a Bragg grating written into a core region thereof with short-pulsed electromagnetic radiation, said optical waveguide having a glass transition temperature substantially higher than that of silica. Preferably the sensor is written into a length of sapphire fiber or within a zirconium waveguide. Preferably the pulse duration of the short pulsed electromagnetic radiation is less than 500 picoseconds.

Abstract: The invention relates to a transmitter identification system, which utilizes an identification signal embedded into a digital television signal, enabling the transmitter of origin to be identified at a receiving station. Ideally the identification signal is an orthogonal pseudo-random sequence time synchronized to the signal frame structure of the digital television signal. Particularly designed for single frequency networks, identification of the various transmitted signals enables the network to be tuned to eliminate or minimize multi-path effects at certain locations, which receive transmissions from various transmitters.

Abstract: The invention relates to an optical waveguide device for monitoring a characteristics of light, e.g. a wavelength. The device incorporates a waveguide, such as an optical fiber, with an embedded tilted Bragg grating operating in a regime of wavelength detuning. The grating is designed to disperse light azimuthally in two or more different directions about the fiber axis, said directions changing with wavelength. A photodetector array is provided for detecting the azimuthal distribution of light. A processor coupled to the photodetector array determines wavelength information from the detected azimuthal distribution of the out-coupled light.

Abstract: A capacitively loaded multilevel transmission line network for operation at a microwave frequency f is disclosed wherein microstrip conductors are disposed over or under a uniplanar transmission line (UTL), electrically connected thereto at or near opposing ends of the UTL and coupled to portions of the UTL separated therefrom by a thin dielectric film. The microstrip conductors and the portions of the UTL coupled thereto form thin-film microstrip (TFMS) shunt stubs capacitively loading the ends of the UTL for increasing its electrical length. The present invention enables considerable size reduction of microwave circuits having uniplanar transmission lines.

Abstract: A planar lightwave circuit device includes one or more planar lightwave circuits (PLCs) each having an optical layer deposited on a substrate, and a package base including one or more support structures for suspending the planar lightwave circuit above a portion of the package base. Each substrate has a first coefficient of thermal expansion, whereas the package base has a second coefficient of thermal expansion. The first and second coefficients of thermal expansion differ such that a change in temperature causes the support to apply one of a compressive and a tensile force to the planar lightwave circuit in a plane within or parallel to the plane of the planar lightwave circuit. The induced stress can modify the optical performance of the PLC device, e.g. to reduce the temperature sensitivity of the device and thus maintain device performance, or for providing efficient passive or dynamic tuning of the device.

Abstract: A novel Bragg grating filter in optical waveguiding fiber with suppressed cladding mode coupling and method of producing same is disclosed. The novel grating structure is induced in both the core and the cladding of the optical fiber irrespective of the photosensitivity of the core or cladding to actinic radiation. Such core and cladding of the optical fiber need not be chemically doped to support the grating. The method incorporates an ultra short duration pulse laser source. Electromagnetic radiation provided from the laser propagates to a diffractive element positioned a specific distance to the target material such that the diffracted electromagnetic radiation forms a 2-beam interference pattern, the peaks of which are sufficiently intense to cause a change in index of refraction.

Abstract: A volume hologram for modifying a characteristic of an input microwave beam and a method for manufacturing thereof are disclosed. The hologram is fabricated from a multi-layer artificial dielectric wherein each layer is made of a dielectric material and includes a lattice of inclusions, for example metal disks disposed on one side thereof, and wherein a pre-determined three-dimensional grating pattern of dielectric perturbations is induced by spatial modulating the lattice of the inclusions. The hologram can be designed for efficiently steering, reshaping, combining or splitting microwave beams.

Abstract: A class of codes and associated methods and devices are provided. Advantageously, such codes when used as constituent codes in composite codes intended for iterative decoding, as compared to the standard practice of using convolutional codes, may allow better error-correcting performance to be achieved, especially at low error rates and high code rates, for a given decoder complexity. State sequencing in these codes is driven not by source data alone, as is the case with convolutional codes, but rather by a sequence that includes both the source data and so-called “inserted” data elements, the inserted data elements having a linear dependence on the state sequencing state. In decoding, state transition intervals involving one or more inserted data elements are handled in a special way.

Abstract: An ultra-wideband antenna for operating in a frequency is disclosed wherein a monopole antenna extends from a ground plane. The monopole has an effective length L of one quarter wavelength at the lowest frequency f1. A dielectric resonator antenna (DRA) surrounds the monopole antenna for resonating at substantially between or at two and three times the lowest frequency f1, the DRA is of a height of less than ¾ L and is disposed in such a manner as being above the ground plane and either contacting or spaced therefrom by a gap G, wherein 0?G?0.2 H. The ultra-wideband antenna is of a much greater bandwidth than the sum of bandwidth of the monople or the DRA alone.