Cavities have been laser ablated in the ends of single-mode optical fibers and sealed by aluminized polycarbonate diaphragms to produce Fabry-Perot pressure sensors. Both conventional fibers and novel, multicore fibers were used, demonstrating the possibility of producing compact arrays of sensors and multiple sensors on an individual fiber 125 microm in diameter. This high spatial resolution can be combined with high temporal resolution by simultaneously interrogating the sensors by using separate laser sources at three wavelengths. Shock tube tests showed a sensor response time of 3 micros to a step increase in pressure.

We describe miniature all-optical pressure sensors, fabricated by wafer etching techniques, less than 1mm 2 in overall cross-section with rise times in the μs regime and pressure ranges typically 900 kPa (9 bar). Their performance is suitable for experimental studies of the pressure-time history for test models exposed to shocks initiated by an explosive charge. The small size and fast response of the sensors promises higher quality data than has been previously available from conventional electrical sensors, with potential improvements to numerical models of blast effects. Results from blast tests are presented in which up to 6 sensors were multiplexed, embedded within test models in a range of orientations relative to the shock front.

Optical fibre pressure sensors have potential performance advantages over electrical sensors in measuring rapid transients such as shock waves from explosive blasts. We report the development of micromachined optical fibre Fabry–Pérot pressure sensors using a silicon dioxide or nitride diaphragm and detail the fabrication stages of the sensor body and diaphragm. The planar technology used is based on silicon deep etching and direct fusion bonding of silicon wafers. Test results for both types of diaphragm are presented. Sensors with rise times better than 3 µs, range 0.1 to 1 MPa and resolution ∼500 Pa have been demonstrated in explosives trials. Despite the difference in the sign of stress for the two diaphragm types, both demonstrated excellent high-speed response to explosively generated air shocks.

We describe miniature all-optical pressure sensors, fabricated by wafer etching techniques, less than 1mm 2 in overall cross-section with rise times in the μs regime and pressure ranges typically 900 kPa (9 bar). Their performance is suitable for experimental studies of the pressure-time history for test models exposed to shocks initiated by an explosive charge. The small size and fast response of the sensors promises higher quality data than has been previously available from conventional electrical sensors, with potential improvements to numerical models of blast effects. Results from blast tests are presented in which up to 6 sensors were multiplexed, embedded within test models in a range of orientations relative to the shock front.

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