Topic
Phase conjugation
About: Phase conjugation is a research topic. Over the lifetime, 3694 publications have been published within this topic receiving 49099 citations.
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TL;DR: In this paper, an experimental program to investigate the properties of an infrared phase conjugation adapative array is described, where both linear and planar adaptive arrays of up to 7 elements using a new integrated frequency phase control technique at 10.6 μm are discussed.
Abstract: Results of an experimental program to investigate the properties of an infrared phase conjugation adapative array are described. Both linear and planar adaptive arrays of up to 7 elements using a new integrated frequency phase control technique at 10.6 μm are discussed. The results presented include correction for atmospheric turbulence at ranges of 1, 6, and 9.5 km. Beam broadening induced by turbulence is reduced to the array diffraction limit and target irradiance fluctuations are decreased by a factor of ≈ 20 in strong turbulence. Received irradiance fluctuations are reduced by ≈ 50 db out to 2 kHz. Beam pointing, scanning, and automatic target acquistion and tracking are demonstrated over the 1 mrad array field of view.
26 citations
TL;DR: It was found that the SPPC mechanism changed from a backscattering and four-wave-mixing mechanism to a cat mechanism when the pump wavelength was varied from 706 to 770 nm.
Abstract: We report what is to our knowledge the first observation of mechanism transformation with wavelength of self-pumped phase conjugation (SPPC) BaTiO3:Ce crystals in the near infrared. in It was found that the SPPC mechanism changed from a backscattering and four-wave-mixing mechanism to a cat mechanism when the pump wavelength was varied from 706 to 770 nm. In addition, SPPC was obtained when the pump beam entered the crystal by the +c face, and a variation with wavelength of optical beam paths in the crystal was also observed.
25 citations
TL;DR: In this article, the time-varying dispersion of ultrafast laser pulses can be self-adaptively stabilized using real-time dynamic spectral holography in semiconductor photorefractive quantum wells.
Abstract: The time-varying dispersion of ultrafast laser pulses can be self-adaptively stabilized using real-time dynamic spectral holography in semiconductor photorefractive quantum wells. Dispersion of all orders is compensated by forming a dynamic spectral-domain hologram of a signal pulse (that has a time-varying dispersion) referenced to a stable clock pulse. The hologram is read out using forward-scattering phase conjugation to remove phase distortion to all orders, including drift in the time of flight. We have achieved adaptive cancellation of time-of-flight excursions up to ±15 ps to an accuracy of ±15 fs with a compensation bandwidth of 1 kHz.
25 citations
TL;DR: In this paper, two different innovative setups allowing nonlinearity cancellation in an embedded link are disclosed, which are simpler than those previously described and strongly improve the performance of high bit-rate transmission systems.
Abstract: One of the main causes of signal degradation in high-bit-rate transmission systems is the interplay between fiber nonlinear effects and dispersion. Different techniques to compensate nonlinear effects in transmission systems, by using an optical phase conjugator, have been proposed in the literature. In this paper, two different innovative setups allowing nonlinearity cancellation in an embedded link are disclosed. The proposed schemes are simpler than those previously described and strongly improve systems performances. The physical mechanism allowing nonlinearity compensation is depicted, and the effectiveness of the proposed solutions is numerically demonstrated. Moreover a new practical method, useful for performance optimization of systems including a phase conjugator, is presented. Results apply to any bit-rate and modulation format.
25 citations
Patent•
14 Nov 1986
TL;DR: In this paper, a self-aligning phase conjugate laser beam that is automatically boresighted with an active or passive tracking sensor is used to measure the angular displacement between the target aimpoint and the locus of the output beam as marked by the oscillator.
Abstract: A method and apparatus for providing a self-aligning phase conjugate laser beam that is automatically boresighted with an active or passive tracking sensor. A single-transverse-mode laser oscillator (12) and a tracking sensor (14) are mounted on opposite sides of an output coupling beamsplitter (15), all attached to a stabilized platform (13) which is part of the inner gimbal of a pointing and tracking system. A multipass laser amplifier (21) with a phase conjugation mirror (22) and an optional nonlinear frequency-conversion device (20) are located off the inner gimbal. The inner gimbal allows rotation of the stabilized platform about an elevation axis (16), and an outer gimbal or pedestal mount permits rotation about an azimuthal axis (17). The phase conjugation mirror (22) compensates the beam for the effects of optical aberrations caused by thermally induced changes in the amplifier medium and the nonlinear medium (if used) and also compensates the beam for angular tilt and jitter in the beam line of sight due to structural flexibility and motion of the stabilized platform. Part of the oscillator output passes through the beamsplitter to the tracking sensor to mark the far-field location of the amplified output beam. The tracking sensor also views a target image after it is reflected by the beamsplitter. The tracking system measures the angular displacement between the target aimpoint and the locus of the output beam as marked by the oscillator and generates tracking error signals which are used to close a servomechanical feedback loop around the gimbal orientation apparatus. Pointing errors resulting from misalignment of the oscillator, the tracking sensor, and the beamsplitter are compensated by this technique.
25 citations