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.

Mainly three technologies are presently commercially available for pressure measurement with fiber-optic sensors: intensity-based, fiber Bragg gratings and Fabry-Pérot. The first one is probably the simplest and the cheapest but it is limited to applications where having 2 fixed or up to 4 flexible fibers is not an issue, whereas the two other technologies require only one fiber. With generally low sensitivity to pressure and prohibitive cost for non multiplexed measurements, fiber Bragg grating pressure sensors are still limited to marginal applications. Fabry-Pérot technology is the best compromise offering at affordable price a great flexibility in terms of pressure ranges, high sensitivity and miniature size suitable for most applications including disposable medical devices.

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Optical fiber sensors have unique advantages and distinctive features that make them very attractive for many applications especially those involving challenging conditions where other traditional electrical sensors usually fail. Among the commercially available optical fiber sensors, the Fabry-Pérot sensing technology is probably the most versatile and the most interesting one since a relatively low-cost universal signal conditioner could easily read compatible Fabry Pérot sensors measuring different physical parameters such as strain, temperature, pressure, displacement, or refractive index. This papers details the numerous advantages of this optical sensing technology and also summarizes the operating modes of commercially available signal conditioners and sensors.

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