Study on the characteristics of ultra-short optical pulse propagation based on short-time Fourier transformation

Short-time Fourier transformation is widely used to expand 1-D signal in temporal domain or spectral domain into the corresponding 2-D case in time-frequency domain.Effect of dispersion and initial chirp of pulse in fiber on signal propagation was numerically analyzed in detail by employing short-time Fourier transformation.Compared with conventional Fourier transformation,short-time Fourier transformation can more directly describe how the temporal and spectral features of optical pulse evolution vary with both dispersion and initial chirp.In addition,the evolutions of new frequency chirp induced by both dispersion and initial chirp can be clearly seen by using time-frequency analysis resulting from short-time Fourier transformation.Therefore,it completely overcomes the disadvantage of conventional Fourier transformation that is used to only compare signal transient in the spectral or temporal domain separately,and short-time Fourier transformation is expected to provide a new and effective approach to analyze the pulse propagation in fiber.