USA as Represented by Secretary of the Navy

John T Redfern

Steven J Cowen

Christopher M Young

Gary A Dressel

James H Daughtry

A high pressure penetrator for use with fiber optic cables is fabricated by method which assures reliable operation. The method of fabrication first calls for providing a bore through the pressure wall of a container of instrumentation. Applying wax to one end of a cylindrically-shaped lens prepares it for alignment in the bore. A suitable lens is the one-half pitch graded refractive index lens of the type marketed under the trademark, SELFOC. The cylindrically-shaped lens is inserted into the bore to locate its far end flush with one side of the wall and so that the wax applied end of the lens lies within the bore at the wall's opposite side. Melting the wax allows it to flow around the tip of the wax applied end of the lens and a subsequent cooling of the melted wax precisely fixes the cylindrically-shaped lens into position within the bore. A high strength epoxy resin is potted in the clearance space between the lens and the bore by vacuum drawing the resin into the clearing space so that, upon curing the resin, the lens will be securely held in place to permit an optical aligning of fibers on either end of the lens to assure optical signal transfer.

Method of making an undersea, high pressure bulkhead penetrator for use

The invention is an apparatus and method for multiplexing digital informan acquired from a multiplicity of data terminals distributed along a conductor of given length. A cyclic synchronization signal consisting of a stream of coding periods is transmitted upon the conductor. The duration of each coding period exceeds the two way travel time through the conductor. The leading edge of a coding period stimulates the transmission of one bit of a digital word stored in each terminal. The bits from the terminals arrive at a system receiver in a time sequence corresponding to the spatial distribution of the terminals. Bits are collected in storage registers according to their significance which is determined by the respective coding period during which they are received. A word from a particular terminal is derived by strobing the output of the storage registers at the time corresponding to the position of the terminal.

Apparatus for multiplexing digital signals

An intrusion sensor uses thin film piezoelectric transducers to sense nea mechanical vibrations. A hose-like sheath contains a pair of insulating strips which carry conductive leaves on their outer surfaces. A series of longitudinally arranged segments of a thin film piezoelectric material are coupled to the leaves to provide signals representative of impinging mechanical vibrations. Since adjacent ones of the thin film segments are alternately polarized, signals are created only when the vibrations are nearby. Greater sensitivity to nearby vibrations is assured when each of the segments is fabricated from several layers of the thin film piezoelectric material.

Piezoelectric vibration detector for sensing a nearby intruder

A single composite cable is deployed between adjacent monitoring stations r sensing an intruder. A number of piezoelectric elements disposed in the cable provide electrical intrusion signals when they are disturbed. Power and triggering pulses for the stations are fed through the cable by a pair of electrical conductors and optical signals representative of the intrusion signals are fed through at least one optical fiber. As a result, the composite cable is relatively lightweight and compact to simplify deployment and it avoids the problems normally associated with crosstalk.

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La Jolla, CA, United States of America

John T Redfern