Determination of the delay time and feedback strength of a semiconductor laser with optical feedback from time series of radiation intensity

A method for estimating the delay time and feedback of a single-mode semiconductor laser from time series of fluctuations of the laser radiation intensity is proposed. The method is based on searching the nearest neighbors of state vectors chosen in time series in a definite way and is resistant to high noise levels. The efficiency of the method is demonstrated by an example of time series of Lang–Kobayashi equations.