Duplex self-mixing interference based on ultra-narrow linewidth fiber ring laser

A novel duplex self mixing interference based on ultra narrow linewidth fiber ring laser is investigated. Dense Wavelength Division Multiplexing (DWDM) is applied to add drop the dual channel vibration signal into the fiber laser. Meanwhile, the output power with optical feedback is theoretically deduced which can not only be interpreted by the well known expression of sell mixing interference but the combination of self mixing interference and mode competition. Experimental results show that different movements of each channel detected from the dual channel fiber laser self mixing interference system are in good agreement with theoretical analysis. Furthermore, a novel system measuring 2-dimensional vibration is introduced in this paper and its potential application to self mixing interference measurement system for high sensitivity, remote and multi dimensional measurement is shown. (C) 2014 Elsevier B.V. All rights reserved.