Fiber optic sensor composition and working principle - Database & Sql Blog Articles

Photocoupler

A fiber optic sensor is a device that converts a measured state into a measurable optical signal. It consists of an optical transmitter, a sensitive component (optical or non-optical), an optical receiver, a signal processing system, and an optical fiber.

Light emitted by the optical transmitter is directed through the source fiber to the sensitive component. At this time, a certain property of the light is modulated by the measurement, the dimmed light is coupled to the optical receiver via the receiving fiber, the optical signal is converted into an electrical signal, and finally the signal is processed to obtain the desired measurement.

Light is an electromagnetic wave E=Asin(ωt+ φ)

Where A is the amplitude vector of the electric field E; ω is the vibration frequency of the light wave; φ is the optical phase; t is the propagation time of the light.

It can be seen that as long as one of the parameters of the intensity, the polarization state (the direction of the vector A), the frequency and the phase of the light varies with the state to be measured, the intensity modulation, the polarization modulation, the frequency modulation or the phase modulation of the light is adopted. After demodulation, the required measured information can be obtained.