Abstract: A radiation source launches a radiant pulse of a desired width into a plurality of parallel-coupled optical sensors for modulation by a quantity to be measured. The modulated output from any two sensors taken in all combinations are interferometrically combined to generate a series of time-separated interference patterns. The interference patterns are probed by a photodetector and vectorially combined to provide the vector gradient of the quantity under measurement.

Abstract: A gradiometer array of two or more sensors consists of a closed housing filled with a volume of fluid having a desired specific gravity. The sensors are freely suspended in the housing by flexible tethers. The sensors have different specific gravities such that one always sinks and the other floats. By that means, the sensors are self-aligning along an axis parallel to the gravitational vertical.

Abstract: An optical encoding goniometer includes a rotatable chamber containing unequal volumes of two immiscible fluids having different indices of refraction and different densities. A plurality of optical fibers are bent to a critical radius and mounted in the chamber. The fiber cladding is exposed in different desired patterns along the bent fibers. The transmissivities of the respective fibers are measured as a function of the angular rotation of said chamber, the transmissivities of the fibers being governed by the radiation bending loss due to immersion of the exposed cladding in one of the two fluids.

Abstract: In this invention, the depth of lapping an optical flat on optic fibers is monitored while the fiber is mounted on the lapping fixture. A collimated light beam is tangentially incident upon the optical flat. A portion of the incident light is transmitted into the optic fiber. A light intensity monitor coupled to the end of the optic fiber measures the amount of transmitted light relative to a standard value. The amount of light transmitted is a function of the surface area of the optical flat. A monitor measurement of a predetermined intensity level indicates sufficient material has been removed from the optical fiber.