Simultaneous Distributed Acoustic and Temperature Sensing Using a Multimode Fiber

Fiber optic distributed acoustic sensor (DAS) and distributed temperature sensor (DTS) are considerably important for many applications. Itis challenging to design a hybrid DAS-DTS system using the same optical fiber because the operation principles of the two sensors are different. We here deploy the widespread standard multimode fiber (MMF) for simultaneous distributed acoustic and temperature sensing. In particular, we operate the MMF in a quasi-single-mode (QSM) state to simultaneously fulfill the functionality requirements of the DAS and DTS. The reported design offers simultaneous vibration and temperature monitoring with high accuracy. In particular, the DAS has a 12.98 dB mean signal-to-noise ratio (SNR) and the DTS offers temperature measurements with ±1 °C accuracy. This technique is significant for many industrial applications because it efficiently tackles a long-standing issue in practical implementation.

I. Introduction

Optical fiber sensors possess numerous advantages including immunity to electromagnetic interference, harsh environment operation, and miniature size [1], [2]. One attractive category of them is the distributed optical fiber sensors which monitor a certain parameter, such as vibration or temperature, along the entire fiber with a predetermined spatial resolution [2]. Such distributed fiber optic sensors are used in a myriad of important applications including oil and gas industry [3], real-time structural health monitoring [4], aerospace transportation [5], among others.