Abstract: A wavelength division multiplexer/demultiplexer having optical path lengths between a fiber array and a Fourier transform lens, and between a dispersion grating and the lens equal to the focal length of the lens. The optical path lengths reduce losses due to angular acceptance mismatch in the multiplexer. Close orientation of the fiber array about the optical axis and the use of a holographic dispersion grating reduces other losses in the system. Multi-exposure holographic dispersion gratings enable the multiplexer/demultiplexer for extremely broad-band simultaneous transmission and reflection operation. Individual Bragg plane sets recorded in the grating are dedicated to and operate efficiently on discrete wavelength ranges.

Abstract: An optical interconnect employing planar volume Bragg hologram technology in two dimensions comprises a dichromated gelatin planar volume Bragg hologram disposed in a glass planar optical path. Multiplexed Bragg plane sets selectively diffract information-bearing light signals such as voice, image, or computer data signals in a VLSI system from a laser diode or LED source coupled to the planar optical path toward high-speed photodiodes. The holographic planar optical interconnect can interconnect up to 1000 different signals between VLSI microelectronic components and systems.

Abstract: A reflective optical wheel speed transducer system is disclosed. The system utilizes a single optical fiber to transmit light to a pair of interrupter discs, and to collect light reflected from the discs. One of the interrupter discs is stationary, and one is rotated at an angular velocity proportional to the rotational speed of a wheel. Both discs are provided with alternating, regularly spaced reflecting and transmissible areas. The reflecting areas of the stationary disc reflect a constant bias level of light to the optical fiber. The reflecting areas of the rotatable disc modulate light passing through the transmissible areas of the stationary disc at a rate proportional to the angular velocity of the wheel. Thus, the interrupter discs generate a modulated light signal that rides on top of the fixed bias signal. Decoding circuitry is provided to convert the modulated component of the light signal to an electrical signal that represents the rotational speed of the wheel.