Method to Determine Length and Starting Point of Waveform Frame from Chaos Time Series in Sensing Applications

We propose a novel method to determine the length and starting point of a waveform frame from a chaos time series in sensing applications. Using similarity of adjacent frame waveforms of an SOA fiber ring laser, we obtain quasiperiodic auto-correction of a chaos waveform, with its quasiperiod equal to the frame length. We study the one-to-one correspondence between positions in a fiber ring and time points in a frame. According to periodicity of self-pulse trains and pseudo-randomness of chaos, we can reveal the repeatedly occurred but hidden self-pulse train by superimposing multiple frames of the chaotic waveforms. Occurrence of self pulse coincides with the frame's starting point. Experimental results show effectiveness of the method. The frame length can be determined by a chaos time series that is slightly longer than one frame. The more the chaos frames are superimposed, the more accurate the frame's starting point can be determined.