Improving the Performance in an Optical feedback Self-mixing Interferometry System using Digital Signal Pre-processing

Y. Yu, University of Wollongong
J. Xi, University of Wollongong
J. F. Chicharo, University of Wollongong

Article comments

This article was originally published as Yu, Y, Xi, J, Chicharo, JF, Improving the Performance in an Optical feedback Self-mixing Interferometry System using Digital Signal Pre-processing, IEEE International Symposium on Intelligent Signal Processing: WISP 2007, 3-5 Oct, 1-6.

Abstract

This paper considers the issue of noise reduction associated with Optical Feedback Self-mixing Interferometries (OFSMI). The objective is to develop an effective pre-processing filtering solution that can eliminated the inherent noise disturbances. The characteristics of OFSMI signals are described in some detail and two filter solutions are proposed. The latter includes a non-linear median filter and a Kaiser based FIR filter. The performance of the two types of filters are removing sparkle-like noise while Kaiser based FIR filters areeffective in reducing the high frequency noise as well as the slow time-varying signal envelop fluctuation. Interestingly our results show that the best performance is achieved by combining the two filters, that is, a median filter followed by a Kaiser-based FIR filter. In other words, the estimation accuracy of OFSMI parameters such as the line-width enhancement factor (LEF) of semiconductor lasers is significantly improved with the aid of the proposed pre-processing solution.