Abstract: A method and system for generating single and multi-channel optical analog pulse-position modulation waveforms are disclosed. The system comprises a frequency modulator, a continuous wave optical source, and an optical modulator. The frequency modulator receives the analog signal and converts the analog signal into a frequency modulated signal. The optical modulator modulates the continuous wave optical source with the frequency modulated signal, to produce the optical pulse-position modulated signal. The method comprises converting an analog input signal into a frequency modulated signal amplifying the frequency modulated signal and producing a large signal therein, modulating a continuous wave optical source with the large signal, therein producing the optical pulse-position modulation signal, and compressing the optical pulse-position modulation signal, therein increasing a processing gain.

Abstract: An integrated optical transmitter includes a modulator drive circuit in communication with a modulator, and a laser drive circuit in communication with a laser. The modulator receives laser light from the laser and modulation control signals from the modulator drive circuit, and outputs modulated optical signals in a direction normal to the substrate surface. The transmitter is integrated by securing the laser to the modulator using flip chip technology. The laser includes a vertical cavity, and is optically aligned with the horizontal coupling surface of the modulator during the flip chip process.

Abstract: A system and technique for directing intensity modulated electromagnetic energy. The inventive system (10) includes an intensity modulated source of electromagnetic energy (12). Individual elements (22) in an array of energy directing elements (15) are activated in sync with the modulation of energy source (12). In a particular implementation, the source (12) is a laser. The intensity of the laser is reduced during each successive field per frame. The energy directing elements (15), in this case--light directing elements, are implemented with an array of digital micromirrors. The light source (12) is modulated in intensity in accordance with a fixed modulation scheme. The mirrors (22) are selectively activated relative to the light source modulation scheme. Hence, the invention provides a gray scale output while allowing the time between mirror flips to be constant.

Abstract: A system and technique for directing intensity modulated electromagnetic energy. The inventive system (10) includes an intensity modulated source of electromagnetic energy (12). Individual elements (22) in an array of energy directing elements (15) are activated in sync with the modulation of the energy source (12). In a particular implementation, the source (12) is a laser. The intensity of the laser is reduced during each successive field per frame. The energy directing elements (15), in this case, light directing elements, are implemented with an array of digital micromirrors. The light source (12) is modulated in intensity in accordance with a fixed modulation scheme. The mirrors (22) are selectively activated relative to the light source modulation scheme. Hence, the invention provides a gray scale output while allowing the time between mirror flips to be constant.

Abstract: Enhanced energy transfers are achieved between optical beams by operating at wavelengths in the near-bandgap region of a photorefractive material, and employing an electrorefractive effect previously proposed only for single beams. An electric field is applied across a photorefractive medium of sufficient intensity to induce an electrorefractive coupling and consequent energy transfer between the beams. Gain enhancements are possible by orienting the photorefractive medium to obtain an electro-optic as well as an electrorefractive effect, and by a moving grating technique. The direction of energy transfer between the beams is controlled by the electric field direction, and can be reversed by reversing the field. Operation in the infrared region is made possible with semi-insulating materials. Applications include optical switches, amplifiers and phase conjugators.

Abstract: An integrated adaptive optics apparatus for processing wavefront errors. In a preferred embodiment, a modified liquid crystal light valve (LCLV) is used as an integrated wavefront sensing and wavefront control system. A remote reference aberrated wavefront 10, passed through the liquid crystal layer and reflected, is then fed-back in part to the rear surface of the liquid crystal light valve 12, after combination with a local reference plane wave 16. The resulting interference pattern is incident on the photosensitive layer 26 of the LCLV, causes commensurate index changes in the liquid crystal layer, and adapts the LCLV for performing aberration correction. In an alternative embodiment, a second laser beam 11 may be predistorted by passing it through the adapted liquid crystal layer in order to compensate in advance for atmospheric path disturbances. The present invention provides an adaptive optics correction system having high spatial resolution.

Abstract: Self-pumped phase conjugation is achieved for optical beams with very short pulse durations by a transient energy transfer mechanism. A probe beam is transmitted through a non-linear optical medium, generating a noise beam from the medium. The probe and noise beams are directed along equal time duration paths, preferably contra-directional to each other, back into the non-linear medium where they mix with each other. The peak probe pulse is thus mixed with the peak noise pulse to optimize gain. The thickness and optical coupling coefficient of the non-linear medium, and the angle between the returned probe and noise beams, are selected to produce a noise beam gain which is sufficient to generate a phase conjugate of the input probe beam.

Abstract: A self-pumped phase conjugate mirror and method is disclosed in which an optical beam is applied to a crystal formed from a photorefractive material, the beam is deflected back into the crystal as a return beam to cross-couple with the input probe beam, and an alternating electric field is applied across the crystal to establish a photorefractive index grating shift of about 90.degree. and bring the crystal gain up to a level at which phase conjugation takes place. By a suitable selection of field strength and frequency, and an angle between the probe and return beams within the crystal of less than about 5.degree. (3.degree. for GaAs), semiconductor materials with electro-optic coefficients of less than about 10 picometers/volt can be used as the conjugating medium.

Abstract: A phase conjugate resonator (PCR) (2) employing a phase conjugate mirror (PCM) (4) provides high resolution spatial detection of individual locations in a two-dimensional optical array which exceed or fall below a threshold level. The optical intensity profile under investigation is imposed onto an input erase beam (18) to the PCM (4). The erase beam (18) is directed parallel to the PCR axis (16), thereby preventing walkoff. The PCR (2) oscillates at those locations where the erase beam's optical intensity is below a threshold level. The spatially modulated optical output may be read out with multiple detectors or an imaging system, or the cumulative area output of the PCR can be read out with a single detector (28) to characterize the intensity profile relative to the threshold.

Abstract: A laser system for providing a rapidly steerable laser output beam. The laser system includes a phase conjugate reflector, laser gain medium and its associated pump source, an output coupling device, and an optical element which selectably controls the transverse lasing mode of the laser system. The components are arranged to form a laser oscillator between the phase conjugate reflector and the optical device, and is operated in such a manner that each selected transverse mode of laser operation generates an output beam from the system which has a different wavefront tilt. Accordingly, the output beam is steerable and is dependent upon the selected transverse mode which is currently lasing in the oscillator.