Optical Fiber Sensors

13Fiber Laser–Based Sensing Technologies

Asrul Izam Azmi, Muhammad Yusof Mohd Noor, Haifeng Qi, Kun Liu, and Gang-Ding Peng

Contents

13.1 Introduction

13.2 Fundamentals of Fiber Lasers

13.2.1 Fiber Laser Types

13.2.2 Laser Phase and Gain Conditions

13.2.2.1 DFBFL

13.2.2.2 DBRFL and CCFL

13.2.3 Laser Characteristics

13.2.3.1 Linewidth

13.2.3.2 Intensity Noise and Frequency Noise

13.2.3.3 Polarization

13.3 Sensing Characteristics of Fiber Lasers

13.3.1 Optimization of Sensing Characteristics

13.4 Interrogation Techniques for FLS

13.4.1 Intensity Interrogation

13.4.2 Wavelength Interrogation

13.4.2.1 Wavelength Interrogation by MZI

13.4.2.2 Digital PGC Demodulation

13.4.2.3 Wavelength Interrogation by MI

13.4.3 Intensity and Wavelength Interrogation ...