Abstract: An optical pressure sensor 10 for measuring the pressure within a container 12 such as a combustion chamber of a rocket engine, wherein pressure sensor 10 comprises a pressure deflectable diaphragm 14 in communication with container 12 and which includes an optical grating 22 on one of its surfaces, means 18 for directing a laser 20 to strike optical grating 22 from a fixed direction to form a central diffracted beam 24 and a first order diffracted beam 26, a photo-position detector 60 for generating signals responsive to the changes in position of the central and first order diffracted beams 24 and 26 resulting from the effects of pressure and temperature upon the diaphragm 14, and means 30 for synthesizing a temperature-adjusted indication of the pressure in the subject container from said responsive signals.

Abstract: This invention relates to a lightweight and compact optical sensor that provides an indication of a deformation (e.g. fatigue, vibration, flex, torsion, bending, slippage) occurring at a monitored area. The sensor includes at least one light transmitting optical fiber and an optical detector that is responsive to the optical characteristics (e.g. amplitude, phase, polarization angle) of a supply of light signals being transmitted through the fiber. In the event that deformation occurs at the monitored region, the optical fiber undergoes a displacement which thereby causes a corresponding change in the optical characteristics of the light signals supplied to the detector. The optical characteristics of the light signals supplied to the detector relative to those of the light signals supplied to the optical fiber provide an accurate indication of the physical parameter.

Abstract: An acoustic wave device wherein each electrode element of an interdigital transducer is buried or embedded between a pair of layers of piezoelectric material. The use of a multi-layer stack of layers of piezoelectric material enables each electrode element of the transducer to be sandwiched between a distinct pair of layers and thus to be insulated from the other electrode element or elements. Because of the insulation thus provided, the spacing between the fingers of each electrode element may be selected without fear of causing short circuits between electrode elements.

Abstract: An inexpensive, non-obtrusive optical flowmeter is disclosed comprising at least one flexible, light transmitting optical fiber rod having an enlarged (e.g. spherical) terminus formed at a fluid responsive end thereof. The flexible optical fiber is inserted into a fluid channel in such a manner that the enlarged terminus oscillates at a frequency that is a function of the rate of fluid flow. The intensity and frequency of an optical signal being transmitted via the optical fiber to an optical detector are related to the rate at which fluid flows through the channel. By detecting the intensity and frequency of the optical signal at different times for corresponding rates of fluid flow, an accurate (digital) representation of a particular rate of fluid flow can be obtained.

Abstract: A Sagnac interferometer gyroscope includes a semiconductor chip on which is formed an optical waveguide. Means are provided on the optical waveguide to inject a laser light beam into the waveguide and onto a divider to produce first and second divided beams. Second and third dividers are provided in the waveguide to generate a reference signal onto a pair of photodectors disposed to receive the divided light waves. The light waves are modulated with first and second frequencies prior to their second division by a pair of Bragg frequency shifter interdigital transducers. The divided and modulated light beams are then directed through an optical path encompassing an axis of sensitivity of the gyro. In one embodiment the path is formed by an optical fiber with connections to the chip. In another embodiment the optical path is defined within the chip itself by reflectors or deflectors at selected locations about the peripheral of the chip.

Abstract: An inexpensive, light weight fiber optic accelerometer to convert input mechanical motion (e.g. acceleration) into digitized optical output signals. The output of the accelerometer may be connected directly to data processing apparatus without the necessity of space consuming analog to digital interface means.

Abstract: An inexpensive, lightweight fiber optic micro-sensor that is suitable for applications which may require remote temperature sensing. The disclosed temperature sensor includes a phosphor material that, after receiving incident light stimulation, is adapted to emit phosphorescent radiation output signals, the amplitude decay rate and wavelength of which are functions of the sensed temperature.

Abstract: An interferometer gyro employing a coiled optical fiber includes a pair of acousto-optic modulators to modulate first and second frequencies onto two components divided from the light of a light source. The light source need not exhibit the high degree of source coherence heretofore required, and can be an incandescent bulb in many applications. The first and second modulated light components are injected in opposite or counter-rotating directions into the optical fiber wherein they experience phase changes due to the apparent change in optical length of the optical fiber upon rotation of the fiber about an axis of sensitivity. The light components are then, after being removed from the fiber, combined and compared with the signals applied at the input. The phase difference therebetween is then established to measure the rate of rotation of the optical fiber about the axis of sensitivity.