Dual-π-phase-shift distributed fiber laser for strain sensing

Abstract

A dual-π-phase shift distributed feedback fiber laser (DFB FL) with symmetric structure is investigated as a strain sensor.The sensing performances under both monolithic and local axial strain are discussed by use of transfer matrix method.While the two lasing wavelengths of dual-π-phase shift DFB FL experience the same change as that of single-π-phase shift DFB FL under monolithic strain, their wavelength interval changes with local strain. And the strain sensitivity of beat frequency is calculated to be 70.6 MHz/με while one phase shift area is insensitive.Dual-π-phase-shift; distributed feedback fiber laser; strain sensing; beat frequency.