Abstract: An optical apparatus for measuring physical quantities, comprising an optical transducer (33) for sensing position, outgoing and return optical fibers (20,23), and an electronic control module (43). Light is generated at the control module and is transmitted by the outgoing optical fiber (20) to the optical transducer (33), which simultaneously varies the relative intensities of two different colors in a dissimilar manner in response to location of a positionable device (34,35) in the optical transducer. The modified intensity is transmitted back to the control module via the return optical fiber (23). The control module (43) measures the intensities of the two returning colors, and then outputs an electrical signal proportional to the intensity ratio for analog applications, or, alternatively, tests the intensity ratio against preselected constants and outputs discrete signals for digital application.

Abstract: A way of terminating an optical fiber is provided by collet-chuck type means which do not involve stripping, crimping or cementing.

Abstract: A fiber optic feedthrough module which comprises a metal sleeve, a fiber optic element extending through the sleeve relation thereto, and a tandem series of centrally-apertured mating annular sealant bodies of thermoplastic material surrounding the fiber optic element and compressed between it and the sleeve. The module is made by first providing a loose sub-assembly of a plurality of individual but interfitting sealant bodies on the fiber optic element and then inserting this subassembly into a metal sleeve, followed by swaging the whole assembly which eliminates clearances and provides sealed interfaces between the various contacting components.