Abstract: A detection apparatus and method for FMCW LIDAR employ signals whose frequencies are modified so that low-cost and low-speed photodetector arrays can be employed for range detection. The LIDAR includes a single mode swept frequency laser (SFL), whose optical frequency is varied with time, as a result of which, a target beam reflected back by the target is shifted in frequency from a reference beam by an amount that is proportional to the relative range z to the target. The reflected target beam is combined with the reference beam and detected by the photodetector array. The difference between the frequencies of the reflected target beam and the reference beam is reduced to a level that is within the bandwidth of the photodetector array by first modulating the target and/or reference beam.

Abstract: This invention relates to opto-electronic systems using semiconductor lasers driven by optical phase-locked loops that control the laser's optical phase and frequency. Feedback control provides a means for precise, wideband control of optical frequency and phase, augmented further by four wave mixing stages and digitally stitched independent optical waveforms for enhanced tunability.

Abstract: A detection apparatus and method for FMCW LIDAR employ signals that are modified so that low-cost and low-speed photodetector arrays, such as CCD or CMOS cameras, can be employed for range detection. The LIDAR is designed to measure the range to one or more targets and includes a single mode swept frequency laser (SFL), whose optical frequency is varied with time, as a result of which, a target beam which is reflected back by the one or more targets is shifted in frequency from a reference beam by an amount that is proportional to the relative range to the one or more targets. The reflected target beam(s) is/are combined with the reference beam and detected by the photodetector array. In the case of a sparse number of targets to be detected, Compressive Sensing (CS) techniques can be employed by a processor to reduce the number of measurements necessary to determine the range of each target.

Abstract: A detection apparatus and method for FMCW LIDAR employ signals whose frequencies are modified so that low-cost and low-speed photodetector arrays, such a can be employed for range detection. The LIDAR is includes a single mode swept frequency laser (SFL), whose optical frequency is varied with time, as a result of which, a target beam reflected back by the target is shifted in frequency from a reference beam by an amount that is proportional to the relative range z to the target. The reflected target beam is combined with the reference beam and detected by the photodetector array. The difference between the frequencies of the reflected target beam and the reference beam is reduced to a level that is within the bandwidth of the photodetector array by first modulating the target and/or reference beam.

Abstract: A chirped diode laser (ChDL) is employed for seeding optical amplifiers and/or dissimilar optical paths, which simultaneously suppresses stimulated Brillouin scattering (SBS) and enables coherent combination. The seed spectrum will appear broadband to suppress the SBS, but the well-defined chirp will have the coherence and duration to allow the active phasing of multiple amplifiers and/or dissimilar optical paths. The phasing is accomplished without optical path-length matching by interfering each amplifier output with a reference, processing the resulting signal with a phase lock loop, and using the error signal to drive an acousto-optic frequency shifter at the front end of each optical amplifier and/or optical path.

Abstract: This invention relates to opto-electronic systems using semiconductor lasers driven by optical phase-locked loops that control the laser's optical phase and frequency. Feedback control provides a means for precise, wideband control of optical frequency and phase, augmented further by four wave mixing stages and digitally stitched independent optical waveforms for enhanced tunability.

Abstract: This invention relates to opto-electronic systems using semiconductor lasers driven by optical phase-locked loops that control the laser's optical phase and frequency. Feedback control provides a means for precise, wideband control of optical frequency and phase, augmented further by four wave mixing stages and digitally stitched independent optical waveforms for enhanced tunability.

Abstract: This invention relates to opto-electronic systems using semiconductor lasers driven by optical phase-locked loops that control the laser's optical phase and frequency. Feedback control provides a means for precise control of optical frequency and phase, including the ability for broadband electronic tunability of optical signals and the cascading of multiple lasers for enhanced tunability and coherent combining for increased output power.

Abstract: Semiconductor diode lasers are phase-locked by direct current injection and combined to form a single coherent output beam. The optical power is amplified by use of fiber amplifiers. Electronically control of the optical phases of each emitter enables power efficient combining of output beams to be maintained under dynamic conditions.

Abstract: This invention relates to opto-electronic systems using semiconductor lasers driven by optical phase-locked loops that control the laser's optical phase and frequency. Feedback control provides a means for precise, wideband control of optical frequency and phase, augmented further by four wave mixing stages and digitally stitched independent optical waveforms for enhanced tunability.

Abstract: Semiconductor diode lasers are phase-locked by direct current injection and combined to form a single coherent output beam. The optical power is amplified by use of fiber amplifiers. Electronically control of the optical phases of each emitter enables power efficient combining of output beams to be maintained under dynamic conditions.

Abstract: This invention relates to opto-electronic systems using semiconductor lasers driven by optical phase-locked loops that control the laser's optical phase and frequency. Feedback control provides a means for precise control of optical frequency and phase, including the ability for broadband electronic tunability of optical signals and the cascading of multiple lasers for enhanced tunability and coherent combining for increased output power.

Abstract: An optical device includes a phase modulator having a waveguide on a substrate. The phase modulator also includes an n-type region having a proximity to a p-type region that causes formation of a depletion region when a bias is not applied to the modulator. The depletion region is at least partially positioned in the light signal carrying region of the waveguide. The phase modulator is tuned by applying a reverse bias to the phase modulator. The reverse bias changes the size of the depletion region.

Abstract: An optical device includes a phase modulator having a waveguide on a substrate. The phase modulator also includes an n-type region having a proximity to a p-type region that causes formation of a depletion region when a bias is not applied to the modulator. The depletion region is at least partially positioned in the light signal carrying region of the waveguide. The phase modulator is tuned by applying a reverse bias to the phase modulator. The reverse bias changes the size of the depletion region.

Abstract: An optical device includes a phase modulator positioned along a branch waveguide of a mach-zehnder interferometer. The phase modulator includes an n-type region having a proximity to a p-type region that causes a depletion region to form when a bias is not applied to the modulator. The depletion region is at least partially positioned in a light signal carrying region of the waveguide.

Abstract: An optical device includes a phase modulator having a waveguide on a substrate. The phase modulator also includes an n-type region having a proximity to a p-type region that causes formation of a depletion region when a bias is not applied to the modulator. The depletion region is at least partially positioned in the light signal carrying region of the waveguide. The phase modulator is tuned by applying a reverse bias to the phase modulator. The reverse bias changes the size of the depletion region.

Abstract: This invention relates to opto-electronic systems using semiconductor lasers driven by feedback control circuits that control the laser's optical phase and frequency. Feedback control provides a means for coherent phased laser array operation and reduced phase noise. Systems and methods to coherently combine a multiplicity of lasers driven to provide high power coherent outputs with tailored spectral and wavefront characteristics are disclosed. Systems of improving the phase noise characteristics of one or more semiconductor lasers are further disclosed.

Abstract: Systems devices and methods in accordance with the invention impart high strength index of refraction patterns to photosensitive optical devices, such as Bragg gratings written in optical fibers. A length of small diameter fiber retaining photosensitivity is fabricated by flame elongation of an optical fiber precursor having dopant containing cladding, using a diffuse, low velocity inverted flame that does not introduce water, OH or H2 into the fiber. By varying the flame velocity during each scan the fiber is diminished to a small, uniform diameter, waist region. Photosensitivity is preserved and enhanced by exposure of the prepared waist region to scanning actinic illumination within an in-diffusing environment of pressurizing hydrogen or deuterium, and controlling the exposure to optimize the photo-induced index change.

Abstract: For systems which disperse individual wavelength components of a DWDM beam into an array of converging beams, the individual wavelength signals are modified for blocking, equalization or other purposes by reflective liquid crystal cells. Thus modulated or modified components are then recombined by the system into an output beam, as by reverse passage through the system. Controlled full extinction or linear attenuation may be introduced by converging asymmetrical beams of separate polarization components for each wavelength into superposed relation on zero twist nematic crystal cells which are voltage controlled so as to retard for extinction of greater than 40 dB or to transform the state of polarization to a selected angle for attenuation. Polarization sensitive elements in the return paths of the reflected beams then filter the rejected components.

Abstract: Systems and methods for modifying, switching, rearranging or otherwise controlling the individual wavelength components of DWDM optical signals are described, which employ compact refolding and reshaping of these dimensionally patterned beams within a confined volume. The wavelength components of the beam are diffractively dispersed with high diffraction efficiency, and then reversely converged to beam waists incident on different ones of an array of control elements such as liquid crystal cells, MEMs and other spatial light modulators, or fixed distributed patterns. With reflective control elements the wavelength components may be reversely refolded along reciprocal paths with rediffraction, to form a reconstituted and revised DWDM output signal. If the control elements transmit at least one of the wavelength components, a separate, adjacent three dimensional beam refolding path, with rediffraction, is used to feed recombined signals to a separate output.