Enhancing the measurement accuracy of a cavity-enhanced fiber chemical sensor by an adaptive filter

Abstract

Amplified spontaneous emission (ASE) noise, induced by an erbium-doped fiber amplifier (EDFA), is always a key problem for the measurement accuracy in a cavity ring-down (CRD) fiber amplified loop gas sensing system. A digital least-mean-square (LMS) adaptive filter is proposed to reduce the ASE noise in a CRD acetylene-sensing fiber loop for improving the measurement accuracy in terms of concentration. The simulation and experimental results show that the measurement accuracy in terms of concentration of acetylene could achieve about 15 ppm.