A strain gage comprising a strained-layer superlattice crystal exhibiting piezoelectric properties is described. A substrate upon which such a strained-layer superlattice crystal has been deposited is attached to an element to be monitored for strain. A light source is focused on the superlattice crystal and the light reflected from, passed through, or emitted from the crystal is gathered and compared with previously obtained optical property data to determine the strain in the element.

Superlattice strain gage

The switching device comprises a switching member with a row of windows, each of which is formed by a separate block of electro-optical material (19) which is connected to a first surface (18) of a rigid carrier (17) by means of an intermediate layer of flexible material (21). Each block comprises two oppositely situated, parallel, light-transmissive principal surfaces (23, 25) and two side surfaces (27, 29) which are also oppositely situated and which extend from one principal surface to the other. On the side surfaces there are provided two electrodes (31, 33) which are connected to two conductors (35, 37) which are constructed as surface wiring. The electrodes and/or the connection between the carrier and the conductors are preferably also formed to be flexible. This construction offers the advantage that the various blocks cannot mechanically or electrically interact with one another.

Switching device for light beams

Acoustic resonances in the acoustically excited photoelastic optically birefringent crystal of an acousto-optic filter are damped by coating the side of the photoelastic crystal with an acoustic absorbing medium, such as tungsten powder loaded epoxy, whereby undesired acoustic resonances are damped. The acoustic impedance of the coating preferably matches the acoustic impedance of the crystal. The outside surface of the crystal is preferably cleaned and roughened to assure an intimate bond between the absorbing material and the crystal medium.

Acousto-optic filter having means for damping acoustic resonances and stray light

A tunable optical filter suitable for use in integrated optical circuits including the combination of a substrate having an optical waveguide such as a thin film thereon. Means such as an optical fiber or grating is provided for introducing light waves in a first mode into the waveguide. An acoustic transducer driven by a tunable electronic signal source is used to propagate acoustic waves on the surface of the waveguide. The optical and acoustic waves interact to produce another optical wave having a mode different than the original optical wave when phase matching conditions are satisfied. A mode filter is located in the waveguide to block the original optical wave and pass the second optical wave.

Electronically tunable optical filter using acoustic waves

An acoustical deflector for electromagnetic waves using a dispersive medium for propagation of the acoustic waves. That is, the thickness of the medium is approximately the wavelength lambda of the acoustic wave so that the phase velocity of the acoustic wave is a function of the acoustic wave frequency. Electromagnetic waves which interact with the acoustic wave fronts are deflected through different angles as the phase velocity of the acoustic wave changes due to frequency changes of this wave. Means are provided to excite an adjustable frequency acoustic wave in the dispersive medium.

Dispersive acoustical deflector for electromagnetic waves

Acoustical ringing which results from piezoelectric effects in an electrooptical modulator is suppressed by mounting the modulator crystal between massive, acoustically absorbent, support members which also provide an electric circuit interface for applying electric signals to the modulator. Solder provides such an absorbent mounting for a lithium tantalate electrooptical modulator crystal. Both solder support members are flowed into place during the same heating interval and permitted to cool simultaneously.

Biazzo Martin R

Papers

Acoustically absorbent mounting method and apparatus for optical modulator