Nanometer resolution fiber-optic-based medical pressure and temperature-measurement system

A prototype, nanometre resolution, single-mode, fibre-based, interferometric medical pressure and temperature sensor system, exploiting low-coherence signal recovery, is demonstrated. These sensors have been designed in such a way that they have similar optical path differences and, hence, the problems associated with multiplexing are greatly reduced. For the pressure sensor, a range to resolution of approximately 6.7 x 10(3):1 and an overall measurement accuracy of better than +/-1% over a pressure range of 0-360 mmHg have been achieved. For the temperature sensor, a measurement resolution of 0.006-degrees-C and a 1% span linearity over a temperature range of 27.3-62.5-degrees-C have been achieved. The performance of both sensors meets or exceeds established medical requirements and the dimensions of the probes are compatible with commercial electric probes, hence this new sensor system is expected to be a practical approach for many medical applications after further engineering.