This paper describes a newly designed all-glass miniature (Ø 125 microm) fiber-optic pressure sensor design that is appropriate for high-volume manufacturing. The fabrication process is based on the chemical etching of specially-designed silica optical fiber, and involves a low number of critical production operations. The presented sensor design can be used with either single-mode or multi-mode lead-in fiber and is compatible with various types of available signal processing techniques. A practical sensor sensitivity exceeding 1000 nm/bar was achieved experimentally, which makes this sensor suitable for low-pressure measurements. The sensor showed high mechanical stability, good quality of optical surfaces, and very high tolerance to pressure overload.

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We have designed a fiber optic sensor for perimeter security based on a Michelson interferometer. Both arms of the interferometer are embedded in a single specially designed cable that is laid under the protected perimeter. Each arm in a cable has a different protective buffer. The transfer of the disturbance caused by the intruder significantly differs between both arms of the interferometer, causing a large phase shift for even the smallest of disturbances. This eliminates the need for complex opto-electronic demodulation schemes traditionally employed in interferometric signal interpretations. Instead, interferometric signal is directly detected and analyzed in frequency domain.

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