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

Abstract

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.

Curcuma longa-Based Optical Sensor for Hydrochloric Acid and Ammonia Vapor Detection

“…The remaining experiments showed a late detection in the first 10 s of exposure; however, other alternatives can be used to speed up detection by using the substrate as a waveguide to measure the change in refractive index as a result of changes in physical properties [ 26 , 27 ]. The plot obtained from exposing 100 µL of pigment to 300 µL of NH 3 showed instability with oscillating peaks.…”

“…As with NH3, an early response of not more than 1 s was observed with a decrease in intensity from 0.18 to 0.08, and then to 0.045 after 5 s at a fixed 600.06 nm (Figures 10 and 11). The remaining experiments showed a late detection in the first 10 s of exposure; however, other alternatives can be used to speed up detection by using the substrate as a waveguide to measure the change in refractive index as a result of changes in physical properties [26,27]. The plot obtained from exposing 100 µL of pigment to 300 µL of NH3 showed…”

Linear Fiber Laser Configurations for Optical Concentration Sensing in Liquid Solutions

“…Since the discovery of laser technology in 1960 by T. H. Maiman, optical fiber sensors were introduced and developed for detecting critical parameters in the processing industries, such as, temperature, refractive index, concentration and strain [1][2][3][4]. Moreover, in the last decades, fiber laser sensors with different configurations have been revealed as a versatile sensing tool for applications in different fields [5].…”