A multi core optical fiber that includes a plurality of cores disposed in a cladding. The plurality of cores include a first core and a second core. The first core has a first propagation constant β.sub.1, the second core has a second propagation constant β.sub.2, the cladding has a cladding propagation constant β.sub.0, and (I).

An apparatus includes an electronic circuit, an electro-acoustic transducer and a coupler. The electronic circuit is configured to receive data to be transmitted over an optical cable, and to convert the data into a modulating signal. The electro-acoustic transducer is configured to convert the modulating signal into an acoustic wave. The coupler is configured to be mechanically coupled to a section of the optical cable, and to apply to the section a longitudinal stretching force that varies responsively to the acoustic wave, so as to modulate the data onto an optical carrier traversing the optical cable.

An apparatus includes an electronic circuit, an electro-acoustic transducer and a coupler. The electronic circuit is configured to receive data to be transmitted over an optical cable, and to convert the data into a modulating signal. The electro-acoustic transducer is configured to convert the modulating signal into an acoustic wave. The coupler is configured to be mechanically coupled to a section of the optical cable, and to apply to the section a longitudinal stretching force that varies responsively to the acoustic wave, so as to modulate the data onto an optical carrier traversing the optical cable.

In a method for forming a holographic image, light is provided to a flat-panel holographic video display that includes waveguide elements that each have a light-guiding substrate and an array of transducers configured to produce a diffraction grating comprising surface acoustic waves. The grating causes the waveguide to outcouple light, focusing it to, or producing wavefront curvatures consistent with it having emanated from, one or more points, in order to form a holographic image. The transducer array may include a large number of densely packed, vertically-adjacent transducers for each hogel for full parallax or may include a small number of vertically-adjacent transducers and a cylindrical optical element for each hogel. The display may be edge-illuminated by a collinear multicolor source. The substrate exit face may have nanopatterned areas alternated with flat areas in order to create regions of optimal internal reflection next to regions of low reflection.

In a method for forming a holographic image, light is provided to a flat-panel holographic video display that includes waveguide elements that each have a light-guiding substrate and an array of transducers configured to produce a diffraction grating comprising surface acoustic waves. The grating causes the waveguide to outcouple light, focusing it to, or producing wavefront curvatures consistent with it having emanated from, one or more points, in order to form a holographic image. The transducer array may include a large number of densely packed, vertically-adjacent transducers for each hogel for full parallax or may include a small number of vertically-adjacent transducers and a cylindrical optical element for each hogel. The display may be edge-illuminated by a collinear multicolor source. The substrate exit face may have nanopatterned areas alternated with flat areas in order to create regions of optimal internal reflection next to regions of low reflection.

Aspects of the present disclosure describe improved distributed acoustic sensing using dynamic range suppression of optical time domain reflectometry either by using a feedback loop comprising optical and electrical elements or using a nonlinear element in the electrical domain after coherent detection. When using a feedback loop, the amplitude of the periodic waveform of coherent OTDR can be inverted. This allows optical pre-compensation of the received optical signal before coherent detection with the goal of minimizing amplitude dynamic range. Alternatively, a nonlinear element in the electrical domain can reduce amplitude dynamic range before sampling by analog-to-digital converters (ADC).

Aspects of the present disclosure describe improved distributed acoustic sensing using dynamic range suppression of optical time domain reflectometry either by using a feedback loop comprising optical and electrical elements or using a nonlinear element in the electrical domain after coherent detection. When using a feedback loop, the amplitude of the periodic waveform of coherent OTDR can be inverted. This allows optical pre-compensation of the received optical signal before coherent detection with the goal of minimizing amplitude dynamic range. Alternatively, a nonlinear element in the electrical domain can reduce amplitude dynamic range before sampling by analog-to-digital converters (ADC).

Systems and methods for steering an optical beam in two dimensions are disclosed. The system includes a substrate comprising an acousto-optic antenna array and an acoustic transducer. Each antenna of the antenna array includes a high-confinement surface waveguide carrying a light signal. The acoustic transducer imparts acoustic energy into each surface waveguide as a mechanical wave. Interaction of the light signal and mechanical wave in each surface waveguide induces light to scatter into free space. The light scattered out of the plurality of waveguides collectively defines the output beam. The longitudinal angle of output beam, relative to the substrate, is determined by the relative frequencies of the mechanical waves and the light signals. The transverse angle of the output beam is controlled by controlling the relative phases of the mechanical waves and/or light signals across the surface-waveguide array.

An illuminating device includes an illumination light generator configured to generate illumination pulses of coherent light, and a speckle modulator configured to modulate speckle caused by the coherent light. The illumination pulse generator repeatedly generates a single illumination pulse group including a plurality of illumination pulses as a repetitive illumination pulse group.

An illuminating device includes an illumination light generator configured to generate illumination pulses of coherent light, and a speckle modulator configured to modulate speckle caused by the coherent light. The illumination pulse generator repeatedly generates a single illumination pulse group including a plurality of illumination pulses as a repetitive illumination pulse group.