Simple hybrid wire-wireless fiber laser sensor by direct photonic generation of beat signal

Abstract

Based on direct photonic generation of a beat signal, a simple hybrid wire-wireless fiber laser sensor is proposed. In the sensor, an improved multilongitudinal modes fiber laser cavity is set up by only a fiber Bragg grating, a section of erbium-doped fiber, and a broadband reflector. A photodetector is used to detect the electrical beat signal. Next, the beat signal including the sensor information can access the wireless network through the wireless transmission. At last, a frequency spectrum analyzer is used to demodulate the sensing information. With this method, the long-distance real-time monitor of the fiber sensor can be realized. The proposed technique offers a simple and cheap way for sensing information of the fiber sensor to access the wireless sensor network. An experiment was implemented to measure the strain and the corresponding root mean square deviation is about -5.7 με at 916 MHz and -3.8 με at 1713 MHz after wireless transmission.