What is the principle of fibre optic sensors?

The basic principle is that the light of the light source through the incident optical fibre into the modulation zone, light in the modulation zone and the external parameters to be measured in the interaction, so that the optical properties of light, such as: intensity, wavelength, frequency, phase, bias state, etc., to change and become a modulated signal light, and then through the outgoing optical fibre into the photodetector, the demodulator and obtain the parameters to be measured.