Stability and Bistability in Feedback Interferometers, and Their Applications

Abstract

On the way to chaotic evolution, bistability and multistability are observed in the outputs of self-mixing semiconductor lasers. In a periodic state, the laser output shows not simply periodic oscillation but also hysteresis. Novel applications have been proposed based on these phenomena, for example, a displacement measurement is performed by counting the fringes obtained from bistable self-mixing interference between the internal field and the optical feedback light in the laser cavity. The direction of the displacement is simultaneously determined from asymmetric waveforms showing hysteresis. We discuss various methods for optical metrology based on self-mixing interference effects in semiconductor lasers. This chapter does not deal with the detailed descriptions of the methods and their accuracies but with the introduction of the principles of the methods.