Fiber Laser Sensor Configurations for Refractive Index, Temperature and Strain: A Review

Fiber laser sensors have been present for almost four decades as versatile sensing devices with a simple demodulation process, high sensitivity, and competitive resolution. This work discusses the most representative fiber laser sensor configurations employed for detecting critical parameters such as temperature, refractive index, and strain. However, essential information about other interesting parameters that have been measured is considered in this manuscript. Concurrently, the sensing elements and principle operation are described. Furthermore, these configurations are analyzed in terms of their principle of operation, sensitivity, gain medium, and wavelength operation range. According to the literature reviewed, fiber laser sensors offer the possibility of new interrogation techniques and simultaneous, independent detection. Considering interferometric fiber sensors, the fiber laser sensors offer high brightness, good output power, and high resolution. As a result, it is demonstrated that fiber laser sensors are a robust alternative for multiple sensing applications.