Macrobending fibre loss filter, ratiometric wavelength measurement and application

摘要

A macrobending standard single-mode fibre (SMF28) is optimized as anedge filter, with the optimal bending radius and length determined according to the bend loss and polarization sensitivity of the bending fibre. An all-fibre ratiometric wavelength system is built and calibrated. The system's accuracy and resolution is discussed with the influence of noise of input signal and photodetectors. Finally, the ratiometric system is employed for the demodulation of FBG strain sensing.