Abstract: A system incorporating a pair of Mach-Zehnder modulators (164,166) for performing amplitude modulation of an optical carrier is disclosed. Each of the modulators is designed to suppress even order distortion products and develop third order distortion products of opposite sign and equal magnitude. The outputs of the two modulators are combined in a directional coupler (155) resulting in substantially suppressing second through fourth order distortion products.

Abstract: In a preferred embodiment this invention provides a second order nonlinear optical film medium which consists of a thermoplastic copolymer which has a crystallographic molecular alignment, and a net dipolar molecular orientation normal to the film plane. The crystallographic molecular alignment is formed by axial mechanical stressing, and the dipolar molecular orientation is induced by an electric or magnetic field.

Abstract: In one embodiment this invention provides a polarization-insensitive interferometric waveguide electrooptic modulator device. In a Mach-Zender type of waveguide geometry, each of the divergent optical paths has a set of electrodes, one of which applies a horizontal electric field and the other a vertical electrical field, respectively, to a nonlinear optically responsive polymeric medium in the optical paths. The polymer medium section between each set of electrodes has a noncentrosymmetric molecular orientation parallel to the respective electric fields.

Abstract: An acoustic transducer is provided that uses a layer of magnetostrictive ferromagnetic material having high magneto-mechanical coupling. The ferromagnetic material is adhered to a part of the outer surface of a resilient rod, so that an incident acoustic signal causes a change in stress in the magnetic material and, in turn, a change in the material's magnetization. An electrical coil surrounds the magnetic material and converts the changing magnetization into an electrical signal. A plurality of transducers may be assembled into an array and towed behind a ship to detect underwater acoustic signals.

Abstract: This invention provides a vibration sensor for detecting vibrations having preselected frequencies. The sensor has a plurality of tuning mechanisms each being mechanically resonant with a different preselected vibrational frequency. The resonating vibrational movements of these tuning mechanisms apply varying stresses to a plurality of glassy magnetostrictive elements associated therewith. Each of the magnetostrictive elements is responsive to a different one of the tuning mechanisms. A magnetic biasing element imparts a magnetization to the magnetostrictive elements and a detecting mechanism associated with the magnetostrictive elements detects changes in the magnetization thereof caused by the varying stresses applied thereto.

Abstract: This invention comprises a vibration sensor for detecting engine knock. The sensor has a tuning mechanism which is mechanically resonant with a preselected vibrational frequency. The resonating movements of this tuning mechanism are adapted to apply varying stress to an associated magnetostrictive element. A magnetic biasing element imparts a magnetization to the magnetostrictive element and a detecting means is associated with the magnetostrictive element for detecting changes in the magnetization caused by the varying applied stress.