Abstract: A novel single sideband electro-optic modulator is characterized by a reentrant waveguide structure. The reentrant waveguide structure allows for a factor of four enhancement of conversion efficiency and a factor of five reduction in phase velocity mismatch between the optical wave and modulating microwave due to microwave dispersion in wideband (2 GHz) operation.

Abstract: A system for the transmission of signals along an optical carrier employs a technique to extend the effective frequency range of modulation beyond that of which a semiconductor laser is capable by combination of signals at the source to form a composite difference signal and recombination at the receiver to restore the original signal.

Abstract: A microwave infrared modulator having a novel three dimensional structure is presented. The modulator includes a waveguide and metal base with a dielectric wafer buried therebetween. The buried wafer allows for conventional microstrip structures to be employed with larger microstrip electrode dimensions than would otherwise be possible.

Abstract: A strain isolation technique for a surface acoustic wave (SAW) device having a piezoelectric SAW substrate is disclosed. A cut in the surface of the piezoelectric SAW substrate forms an isolated surface region where active SAW signal propagation occurs. The cut prevents undesirable surface strains from affecting SAW signal propagation in the isolated region.

Abstract: Temperature compensation is provided to a surface acoustic wave device including acoustoelectric transducers (12, 14) formed on a surface of a gallium arsenide substrate (10), by a composite layer including silicon dioxide (18, 26) and a mass loading metal (20, 24), which may be gold, titanium and gold, or other metals having Rayleigh wave velocities lower than that of gallium arsenide, such as silver and platinum.

Abstract: An accelerometer comprising a mass 10 supported on a piezoelectric cantilevered beam 12 with SAW resonators 17, 46 disposed on the surface of the beam includes cover plates 66, 68 over the SAW resonators and sealed to the beam by seals 70, 72 which may be rigid (glass frit) or soft (filled polyimid).

Abstract: Mode locked surface acoustic wave oscillators, configured as comb spectrum generators, are stabilized by means of a variable phase in the closed, oscillation loop, the phase being controlled in response to deviations of the low, pulse repetition frequency from a design reference PRF. The variable phase may be provided by a variable phase device inserted in the oscillatory loop, such as varactor-tuned lumped element delay lines or 90.degree. hybrids, or other devices. Or, the variable phase may be provided by a voltage tunable surface acoustic wave device used as the basic oscillator SAW delay line.

Abstract: A broadband microwave waveguide modulator uses microwave signal frequencies to provide phase modulation of an infrared laser propagating in a guided mode through a common electrooptic interaction region in the form of a microstrip transmission line, provided by electroplating microwave electrodes on each of two mutually opposed major surfaces of a monolithic, thin-film optical waveguide having uniform thickness, to provide a high efficiency conversion of a portion of the laser carrier power into optical sideband signals.

Abstract: A mode-locked surface acoustic wave oscillator (MLSO) provides mode-locked, phase coherent RF signal pulses through a regenerative closed loop RF signal path which includes a surface acoustic wave (SAW) delay line having a piezoelectric substrate and a pair of signal transducers relatively disposed at a determined SAW propagation distance along a major surface thereof, an RF amplifier to provide in phase amplification of the RF pulse, and a signal expander circuit for providing an increase in the harmonic frequencies of the RF signal pulse and an increased RF pulse frequency bandwidth. The pulse repetition frequency is determined by the signal propagation time delay, provided primarily by the SAW delay line. The delay line transducers establish the center frequency of the RF signal pulse and the bandwidth of the regenerative loop limits the minimum obtainable RF pulse width.

Abstract: A nonlinear delay line correlator and convolver is described which comprises a tapped, piezoelectric surface acoustic wave delay line and an array of series or parallel connected forward biased semiconductor diodes. An interdigital signal transducer is connected to each end of the delay line and voltages are applied to each transducer to generate contra-flowing acoustic strain waves which are radiated toward an interaction region comprising a plurality of equi-spaced weakly coupled interdigital transducers, each transducer being connected to one diode. Nonlinear signal mixing in the diode array is utilized to perform serial product convolution or correlation of the signal modulation applied at the two signal input transducers. Because of the large nonlinearity of semiconductor diodes, insertion loss is relatively low.