Abstract: An RF power controller arrangement prevents excessive RF power-based thermal loading of an RF signal processing device, such an as acousto-optic modulator, by controllably constraining the product of the average on-duration of a baseband modulation signal and RF input power to realize no more than a prescribed value of RF energy supplied to the modulator.

Abstract: An RF power controller arrangement prevents excessive RF power-based thermal loading of an RF signal processing device, such an as acousto-optic modulator, by controllably constraining the product of the average on-duration of a baseband modulation signal and RF input power to realize no more than a prescribed value of RF energy supplied to the modulator.

Abstract: A multi-channel acousto-optic modulator contains an integrated structure for providing active compensation for transient thermal effects. A plurality of electro-thermal elements in the form of resistive strips are interleaved with acoustic wave launching transducers, to which signals are applied for modulating respective acoustic waves launched into an acousto-optic medium. The resistive strips receive electrical signals that controllably introduce respective thermal energy components into the acousto-optic medium adjacent to the signal launch transducers, in a manner that causes the overall spatial distribution of thermal energy in the acousto-optic medium to have a prescribed characteristic. By establishing an thermal gradient characteristic across all the channels of the RF signal processor, and compensating each channel on an individual basis, the invention effectively compensates for time-dependent variations in heating, resulting in a substantially level thermal behavior.

Abstract: An apparatus for generating a pattern on a photomask includes a beam generator generating a row of spaced apart optical beams, a blocking element downstream from the beam generator in a path of at least one of the optical beams, and a refracting element downstream from the blocking element for aligning optical beams closer together and while leaving an enlarged beam spacing downstream from the at least one blocked optical beam. The apparatus further includes a modulator downstream from the refracting element for defining the pattern to be generated on the photomask. The apparatus generates the row of spaced apart optical beams with an enlarged beam spacing between the two central beams without using high precision mirrors that are expensive to produce and requires precise alignment with respect to one another.

Abstract: A mode-locked cavity-dumped laser in which the dumping is phase-coherently synchronized with the mode locking. An acousto-optic modulator is employed in the cavity for dumping. On two passes through the modulator, an envelope pulse of light has two portions deflected to a common output path, one of the portions being shifted upward in frequency and the other downward, by an amount equal to the acoustic excitation frequency. The ability of the modulator to provide output power is therefore envelope-modulated at twice the acoustic frequency. The power of successive output pulses is maintained uniform by synchronizing the phase of the circulating mode-locked pulses with respect to the phase of the envelope modulation.