Abstract: For use, e.g., in the compensation of frequency dispersion in the course of transmission of an optical signal, a pulse-shaping device is provided with a suitably shaped nonplanar mirror (16). When spatially spread-out frequency components--produced, e.g., by a grating (14)--are reflected from such mirror, a frequency-dependent phase shift is introduced; for example, such phase shift may be a third-order function of frequency. Upon recombination of frequencies, a shaped pulse is obtained. Furthermore, third-order compensation can be used to compress amplified light pulses, e.g. as produced by a semiconductor gain medium (80, 81).

Abstract: A tapered single-mode rib waveguide for which only laterally patterning is required. A sublayer is disposed between the low-index substrate and the high-index rib and has an intermediate index. Preferably a thin buffer layer of very low refractive index is disposed between the rib and the sublayer. The widths of the rib are chosen so that in a wide portion the optical power of the single-mode is concentrated in the rib or buffer layer but in a narrow portion the optical power is concentrated in the sublayer or substrate and additionally has a wide lateral distribution. A similar effect can be obtained by tapering an upper rib disposed on top of an untapered lower rib.

Abstract: A bistable nematic liquid crystal display cell is electrically switched between topologically equivalent, asymmetric horizontal states. The cell includes upper and lower parallel substrates, upper and lower topographically textured tilt alignment surfaces on the corresponding substrates, and nematic liquid crystal material between the substrates. In an active region of the cell, the tilt alignment surfaces form an unequal reverse tilt boundary condition. In an isolation region surrounding the active region of the cell, the tilt alignment surfaces are formed to avoid the reverse tilt boundary condition.

Abstract: A bistable nematic liquid crystal display cell is switched between topologically equivalent, asymmetric horizontal states. Switching is initiated by application of a directional, symmetry breaking field such as a transverse magnetic field. An electric potential is then applied across the cell to complete the switching cycle and maintain the state. The cell includes upper and lower parallel substrates, upper and lower topographically textured tilt alignment surfaces on the corresponding substrates, and nematic liquid crystal material between the substrates. In an active region of the cell, the tilt alignment surfaces form an equal reverse tilt boundary condition. In an isolation region surrounding the active region of the cell, the tilt alignment surfaces form a parallel tilt boundary condition.