Fiber-optic temperature sensor using an optoelectronic oscillator

In this letter, a fiber-optic temperature sensor using an optoelectronic oscillator (OEO) has been proposed and experimentally demonstrated. Part of the fiber in the oscillator loop is taken as the sensing fiber. Since the free spectrum range of the OEO is determined by the length of the oscillator loop, and when the temperature of the sensing fiber is changed, the refractive index of the fiber varies, and thus the optical path length of the oscillator loop changes as well as the free spectrum range of the OEO. By tracking the frequency of one of the oscillator peaks, the temperature variation can be monitored. By using the proposed fiber-optic temperature sensor, the temperature variation can be converted to the frequency shift of the RF signal, which facilitates the measurement, and also this proposed sensor enjoys good sensing linearity, the ease of implementation and remote sensing, thus shows good potential in the practical applications.