Abstract: The invention is a Demodulator for an Optical Analog Pulse Position Modulated signal suitable for inclusion in receivers for Free Space Optical communication systems. In one embodiment the Demodulator may use the pulse position modulated optical information signal and the clock signal with different wavelengths. By proper biasing of a Semiconductor Optical Amplifier and selection of wavelengths for the information signal and the clock signal, the performance of the Demodulator is made insensitive to noise in the received signals.

Abstract: The invention is a Demodulator for an Optical Analog Pulse Position Modulated signal suitable for inclusion in receivers for Free Space Optical communication systems. In one embodiment the Demodulator may use the pulse position modulated optical information signal and the clock signal with different wavelengths. By proper biasing of a Semiconductor Optical Amplifier and selection of wavelengths for the information signal and the clock signal, the performance of the Demodulator is made insensitive to noise in the received signals.

Abstract: A coherent laser receiver for receiving encoded light which may have propagated over an aberrated path, situated between a source of the encoded light and the coherent receiver. The coherent laser receiver comprises a bundle of optical fibers arranged in an array to receive light, as encoded from a distant optical transmitter or reflective surface, the encoded light from the distant optical transmitter or reflective surface is received by at least a majority of the fibers in the array. A plurality of light amplifiers is provided for amplifying the received encoded light.

Abstract: An optical pulse position modulator includes a substrate with parallel first and second sides, the substrate including a first waveguide channel and a parallel second waveguide channel orthogonal to the first and second sides, a linear chirped grating orthogonal to and upon the first and second waveguide channels, and at least a first electrode along the first waveguide channel to apply a voltage modulation thereto. A first optical circulator has a first port coupled to a pulsed optical carrier signal, and a second port coupled to the first waveguide channel on the first side of the substrate, and a second optical circulator has a fourth port coupled to the third port of the first optical circulator, and a fifth port coupled to the second waveguide channel on the second side of the substrate. An output of the second waveguide channel is a position modulated optical pulse signal.

Abstract: A laser apparatus having multiple laser devices coupled together. The laser devices comprise optical fibers with laser active regions. Each of the fibers has a reflector disposed at one end and is connected to a combiner on the other end. A laser pump device for each fiber provides pump energy to the laser active regions. Light propagating in the fibers interacts so as to form inphase states. The array of fibers may be coupled either in pairs or altogether between the reflector and the laser active region.

Abstract: A fiber optic apparatus formed by fusing together multiple optical fibers and stretching the fused optical fibers to form a tapered portion. The tapered portion is cleaved or cut and polished to form a facet at which an optical beam is received or transmitted.

Abstract: A laser apparatus having multiple laser devices coupled together. The laser devices include optical fibers with laser active regions. Each of the fibers has a reflector disposed at one end and is connected to a combiner on the other end. A laser pump device for each fiber provides pump energy to the laser active regions. Light propagating in the fibers interacts so as to form inphase states. The array of fibers may be coupled either in pairs or altogether between the reflector and the laser active region.

Abstract: A multiple-fiber, stretched, fused and cleaved coupler designed to act as an output window to a fiber laser array or fiber-coupled laser array, in which the stretch, length and/or position of the fibers is chosen facilitate the in-phase oscillation of the lasers in the array. The in-phase oscillation of the lasers is facilitated by making one or more of the fibers interferometrically dark. The other fibers, the interferometrically lit ones, are made to have fairly uniform intensity under the same collimated illumination.

Abstract: A laser apparatus having multiple laser devices coupled together. The laser devices comprise optical fibers with laser active regions. Each of the fibers has a reflector disposed at one end and is connected to a combiner on the other end. A laser pump device for each fiber provides pump energy to the laser active regions. Light propagating in the fibers interacts so as to form inphase states. The array of fibers may be coupled either in pairs or altogether between the reflector and the laser active region.

Abstract: A method and apparatus for compensating for phase fluctuations incurred by an optical beam travelling through free space, especially a turbulent atmosphere. A transmitting station transmits a plurality of uniquely tagged optical beams through free space. The plurality of uniquely tagged optical beams are received at a receiving station, where a parameter of each uniquely tagged optical beam is quantified. Information associated with the quantified parameter for each uniquely tagged optical beam is then sent back to the transmitting station via a wireless feedback link. Using the information, the transmitting station adjusts at least one uniquely tagged optical beam to compensate for phase fluctuations.

Abstract: A multiple-fiber, stretched, fused and cleaved coupler designed to act as an output window to a fiber laser array or fiber-coupled laser array, in which the stretch, length and/or position of the fibers is chosen facilitate the in-phase oscillation of the lasers in the array. The in-phase oscillation of the lasers is facilitated by making one or more of the fibers interferometrically dark and having a different propagation constant than the other fibers. The other fibers, the interferometrically lit ones, are made to have fairly uniform intensity under the same collimated illumination.

Abstract: A phase-conjugate mirror has a length of hollow core photonic crystal multi-spatial mode, polarization-maintaining fiber disposed in a vessel, with a compressible and preferably gaseous medium, such as Xe or CH4, occupying the hollow core of the of hollow core photonic crystal fiber and surrounding the exterior of the hollow core photonic crystal fiber. At least one sealed window is provided in the vessel, the at least one sealed window being optically coupled to at least one end of the length of hollow core photonic crystal fiber.

Abstract: A system and a method for remotely sensing global motion of an ensemble of dynamically moving scattering sites. The system comprising a scattering medium under inspection, an optical transceiver and a detector in a double-pass geometry.

Abstract: A method and apparatus for generating single polarization fiber laser output are disclosed. A Bragg grating is non-destructively fabricated within the fiber to introduce differential loss between the two polarizations of the laser output. Curvature at the grating site into a tight loop further increases the differential loss between the available polarizations.

Abstract: A system and a method for remotely sensing global motion of an ensemble of dynamically moving scattering sites. The system comprising a scattering medium under inspection, an optical transceiver and a detector in a double-pass geometry.

Abstract: A fiber optic apparatus formed by fusing together multiple optical fibers and stretching the fused optical fibers to form a tapered portion. The tapered portion is cleaved or cut and polished to form a facet at which an optical beam is received or transmitted.

Abstract: A laser apparatus having multiple laser devices coupled together. The laser devices comprise optical fibers with laser active regions. Each of the fibers has a reflector disposed at one end and is connected to a combiner on the other end. A laser pump device for each fiber provides pump energy to the laser active regions. Light propagating in the fibers interacts so as to form inphase states. The array of fibers may be coupled either in pairs or altogether between the reflector and the laser active region.

Abstract: A method and apparatus for compensating for phase fluctuations incurred by an optical beam travelling through free space, especially a turbulent atmosphere. A transmitting station transmits a plurality of uniquely tagged optical beams through free space. The plurality of uniquely tagged optical beams are received at a receiving station, where a parameter of each uniquely tagged optical beam is quantified. Information associated with the quantified parameter for each uniquely tagged optical beam is then sent back to the transmitting station via a wireless feedback link. Using the information, the transmitting station adjusts at least one uniquely tagged optical beam to compensate for phase fluctuations.

Abstract: The present invention provides for the coupling of laser diodes into electromagnetic radiation transmitting fibers wherein coupling efficiency is improved by improving the spatial brightness of multi-mode diode lasers as they are coupled into double-clad fibers. A Bragg grating 100 is fabricated into the core 102 of a double-clad fiber 104 coupled to a multi-mode diode laser 106. The output 108 from the multi-mode diode laser 106 is coupled into the core 102 and inner cladding 110 of the double-clad fiber by proximity or by one or more focusing objectives 112. The Bragg grating 100 in the core 102 of the double-clad fiber 104 is written at the wavelength of the multi-mode diode laser 106. The original output 108 from the multi-mode diode laser 106 strikes the Bragg grating 100 which reflects feedback 114 back to the diode laser 106.

Abstract: The present invention provides for the coupling of laser diodes into electromagnetic radiation transmitting fibers wherein coupling efficiency is improved by improving the spatial brightness of multi-mode diode lasers as they are coupled into double-clad fibers. A Bragg grating 100 is fabricated into the core 102 of a double-clad fiber 104 coupled to a multi-mode diode laser 106. The output 108 from the multi-mode diode laser 106 is coupled into the core 102 and inner cladding 110 of the double-clad fiber by proximity or by one or more focusing objectives 112. The Bragg grating 100 in the core 102 of the double-clad fiber 104 is written at the wavelength of the multi-mode diode laser 106. The original output 108 from the multi-mode diode laser 106 strikes the Bragg grating 100 which reflects feedback 114 back to the diode laser 106.