Abstract: The present invention is directed to an optical coupler, only formed by a plurality of all plastic fibers, and a method of producing the same. Two all plastic fibers each of which has a core are placed in contact with each other over a predetermined length. Ultrasonic vibration is applied to a contacting portion of the all plastic fibers so as to bond the cores with each other at the contacting portion. Thus, the optical coupler with a low-excess-loss can easily be produced.

Abstract: An optical power summing apparatus that allows a multiplicity of optical signals to be combined with minimal signal transmission loss. A single photodiode simultaneously receives all of the input signals to perform a summation of signal powers. Alternative embodiments of the apparatus use either a tightly packed bundle of etched optical fibers or a converging arrangement of optical waveguides on a dielectric substrate to focus the optical signals onto the base region of a single photodiode.

Abstract: A method for fabricating a high efficiency optical coupler by matching the emerging light exit pupil from a coupler opening to the acceptance shape of a couple optical fiber. An excimer laser forms the coupler opening in an optical fiber by removing cladding from the optical core surface. The coupler opening has an elliptical shape resulting in an emerging light exit cone, and that exit cone matches an acceptance cone of a circular coupler optical fiber.

Abstract: An optical waveguide star coupler includes a light propagating core provided on a substrate. An exciting light and a signal light are supplied to the light propagating core. The light propagating core includes a plurality of Y-branching waveguides connected one after another to provide a multi-stage waveguide structure. A signal light inputted in the core is combined during the propagation through the core with the exciting light so that the signal light is amplified.

Abstract: A 2.times.2 polarization beam splitter comprising two parallel waveguides and two crossing waveguides coupled in an X-configuration to the parallel waveguides by four adiabatic .gamma.-junctions which transfer only one of the two orthogonal polarization modes across the junctions, e.g., the TE mode. The crossing waveguides may be of different widths and cross at a very shallow angle so that little cross-talk occurs at the crossing.

Abstract: Waveguide-type optical switch comprising a substrate, branched first and second waveguide routes provided thereon, and an electrode(s) provided on the substrate for controlling the propagation-constant difference or refractive index difference between the first and second waveguide routes. The interval between the first and second waveguide routes is extended towards the terminal end sides from the branch point side of the waveguide routes. The first and second waveguide routes are provided with a branched part. The first and second waveguide routes are provided with at least one part of the bending portions (II) connected to the branch part, respectively. The local branch angle between the first and second waveguide routes on the side of starting ends of the bending portions (II) is enlarged while the local branch angle between the first and second waveguide routes on the side of terminal ends at the bending portions (II) is reduced.

Abstract: A fiber optical Y-junction device includes a l.times.N optical fiber coupler connected to N fiber optic amplifier module structures constructed from a doped optical fiber. When the optical Y-junction structure contains a fiber optic amplifier, the fiber optical Y-junction device is operable as either a modulator or lossless power divider. A nonblocking optical switch is constructed by coupling M.times.l optical fiber couplers to the outputs of the fiber optic amplifier module structures utilizing the fiber optical Y-junction.

Abstract: When two hollow tubular light conduits are interconnected at a miter joint, beamed light can be redirected from one of the conduits to the other by a thin transparent prismatic element that is mounted to extend along the plane of the miter joint. When the interconnected conduits are acting as a luminaire, the miter joint can be fully illuminated by the transported light. A luminaire of unlimited length can be obtained by mounting a plurality of lamps and parabolic reflectors along a transparent hollow tubular light conduit and redirecting light from each lamp to be transported along the axis of the conduit in both directions.

Abstract: The single-wavelength bit-rate capacity of an ultra long distance soliton transmission system is increased by using a combination of polarization and time-division multiplexing. More specifically, two streams of differently (preferably orthogonally) polarized solitons are interleaved (time division multiplexed) at a transmitter, and later separated at the receiver to recover both data streams. The system operates at speeds of up to 7.5 GHZ and provides very thorough separation of channels required for 10.sup.-12 error rates at distances of 9000 km.

Abstract: This polarization beam splitter for guided light is e.g. produced on Z-propagating, X-cut LiNbO.sub.3 :Ti and comprises in series a passive Y-junction (66), an active phase shifter (68) and an active directional coupler (70), independent of the polarization and able to constitute a 3 dB coupler. Thus, on supplying a light wave to the input of the Y-branch and with the coupler constituting a 3 dB coupler, the TM and TE modes of the input wave are respectively obtained at the outputs of the coupler by appropriately polarizing the phase shifter. Application to optical fiber sensors or transducers and to the coherent transmission of information by monomode optical fibers.

Abstract: A broadband optical source with a flat spectral output and high output power for use in a fiber optic sensor interface system. The broadband optical source comprises N optical sources such as LEDs, where N is a positive integer greater than 1. The N optical sources output a plurality of optical signals having center wavelengths .lambda.i, spectral widths .DELTA..lambda.i and powers Pi, where i is a positive integer corresponding to each of the N optical sources. The broadband LED source also comprises a waveguide coupler for receiving and combining said plurality of optical signals and for outputting a broadband optical signal. The broadband LED source outputs extremely spectrally flat, broadband signals when the center wavelengths .lambda.i are separated by approximately 2/3 of the spectral widths .DELTA..lambda.i.

Abstract: Optical communication methods and apparatus are disclosed for transmitting two or more optical signals with different optical carrier frequencies on a single optical fiber with high spectral efficiency. Each optical carrier is typically modulated with multiple modulated subcarriers. In one embodiment, an optical phase modulator provides cancellation of second order intermodulation products in each optical signal, thereby permitting the optical carrier frequencies to be spaced by 2f.sub.max, where f.sub.max is the maximum modulation frequency. In another embodiment, a single sideband optical phase modulator provides cancellation of second order intermodulation products and one signal sideband, thereby permitting the optical carrier frequencies to be spaced by f.sub.max. Quadrature optical phase modulators for simultaneous transmission of two independent baseband digital data signals or two independent subcarrier multiplexed signals are disclosed.

Abstract: A wavelength selective structure is coupled to an adiabatic Y-coupler via a multimode section which supports both symmetric and antisymmetric modes. One single mode branch of the coupler converts guided light to a symmetric mode, whereas the other single mode branch converts guided light to an anti-symmetric mode. The structure, which includes a pair of single mode waveguide arms coupled to the common section and a reflection device (such as a grating or ROR) located in each arm, converts reflected light from a symmetric mode to an anti-symmetric mode and conversely. Applications described include a channel dropping filter and channel balancing apparatus for WDM systems, and a dispersion compensator for fiber optic systems.

Abstract: In a digital switching center for a telephone switching system or the like, a clock signal distribution arrangement having a redundant central clock generator supplying clock signals to the switching matrices the arrangement including electro-optical transducers, brancher modules, light conductors and opto-electrical transducers connected in signal distribution paths between the clock generator and the switching matrices. The distribution paths are doubled for redundancy purposes.

Abstract: A wavelength selective structure is coupled to an adiabatic Y-coupler via a multimode section which supports both symmetric and antisymmetric modes. One single mode branch of the coupler converts guided light to a symmetric mode, whereas the other single mode branch converts guided light to an anti-symmetric mode. The structure, which includes a pair of single mode waveguide arms coupled to the common section and a reflection device (such as a grating or ROR) located in each arm, converts reflected light from a symmetric mode to an anti-symmetric mode and conversely. Applications described include a channel dropping filter and channel balancing apparatus for WDM systems, and a dispersion compensator for fiber optic systems.

Abstract: Disclosed is a planar optical waveguide that is manufacturable by the compression molding or embossing of a multilayer film of polymeric material. In one embodiment, the waveguide comprises a core layer of relatively high refractive index included between cladding layers of lower refractive index. The waveguiding channels are bounded by regions where the cladding layers are in contact and from which core material has been excluded.