Radon-Wigner transform processing for optical communication signals

The temporal Radon-Wigner transform (RWT), which is the squared modulus of the fractional Fourier transform (FRT) for a varying fractional order p, is here employed as a processing tool for pulses with FWHM of ps-tens of ps, commonly found in fiber optic transmission systems. To synthesize the processed pulse, a selected FRT irradiance is optically produced employing a photonic device that combines quadratic phase modulation and dispersive transmission. For analysis purposes, the complete numerical RWT display generation, with 0 < p < 1, is proposed to select a particular pulse shape related to a determined value of p. To this end, the amplitude and phase of the signal to be processed should be known. In order to obtain this information we use a pulse characterization method based on two intensity detections and consider the amplitude and phase errors of the recovered signal to evaluate their impact on the RWT production. Numerical simulations are performed to illustrate the implementation of the proposed method. The technique is applied to process optical communication signals, such as chirped Gaussian pulses, pulses distorted by group velocity dispersion and self-phase modulated pulses. The processing of pulses affected by polarization effects is also explored by means of the proposed method.