Question

Which of the following is the principle behind  Fluoroptic temperature sensors working?

(a) optical fiber

(b) thermistor

(c) thermocouple

(d) rtd

I had been asked this question during an interview.

This is a very interesting question from Transmission of Analog Physiological Signals Over Telephone topic in division Biomedical Telemetry of Biomedical Instrumentation

Answer 1

Right option is (a) optical fiber

Explanation: They contain a rare earth phosphor which is illuminated by a white light along a short length of large core optical fibre. Fluoroptic temperature sensors work on the principle of optical fiber sensors.  The light excites the phosphor which emits a number of lines. By using filters, two of these lines at 540 and 630 nm are selected, and the ratio of their intensities is a single valued function of the temperature of the phosphor.