Abstract: A laser beam profile sensor system for which is capable of accurately determining distances to both close and distant objects, particles, liquid interfaces and the like and of identifying the locations of ice layers on metal surfaces. Basically, the system includes a laser diode for generating a laser beam along a selected path, a receiver spaced from the laser diode for receiving light along a receiver axis, the laser beam and receiver axis intersecting at any desired angle from nearly 0.degree. to nearly 180.degree.. The receiver comprises a linear array of light responsive elements. An optical system is provided for directing light approaching the receiver along the receiver axis to the array. An electronic circuit processes signals from the array elements and produces a display showing the distance to any target lying along the laser beam path that reflects light along the receiver axis.

Abstract: Method and arrangement for locking a laser to an external cavity that is electronically tunable to provide an optical source that is highly coherent and which is frequency stabilized over a variable frequency range. Preferably, an injection laser is tightly coupled to an external acousto-optic cavity having a reflective mirror on its back facet and carried on an electro-optic crystal substrate. A transducer is coupled to the external cavity and converts an electrical sinusoidal input signal into an acoustic wave which travels along the electro-optic crystal substrate to modulate the refractive index of the material along the optical waveguide. The periodicity of the refractive index along the waveguide is accordingly determined to be equal to one half wavelength of the acoustic frequency propagating in the waveguide which locks the laser at a particular optical frequency determined by the refractive index profile. The arrangement is particularly desirable for frequency division multiplexing applications.

Abstract: A circuit arrangement to convert high voltage direct current energy into radio frequency energy that includes photoconductive switch means which is periodically closed by a pulsed light source, such as a laser, to generate the radio frequency energy. A segmented transmission line which includes a plurality of photoconductive switches positioned a half-wavelength apart that are closed simultaneously by the laser may be used to generate the radio frequency energy. The photoconductive switches may also be connected in parallel and closed by time delayed light pulses to generate the radio frequency energy. The pulses generated may also be used to excite a resonator circuit coupled to a load to increase the duration of the high frequency oscillation and to shape (filter) the resultant waveform. Other configurations utilizing photoconductive semiconductor discs and annular metal electrode configurations which may be closed by light pulses are also illustrated.

Abstract: An injection laser is provided with a modulator which includes an external resonator cavity including a lithium niobate crystal and a spherical mirror closely coupled to the rear end of the laser with a source of bias voltage for selectively tuning the resonator for high frequency modulating the laser.

Abstract: A broadband optical spectrum analyzer analyzes RF frequencies by modulating a laser beam at its source with the RF frequencies. The modulated laser beam is collimated and directed to a reflection means where signal components of different frequencies are reflected at different angles. Rays of the same spectral range are collected and interpreted.