A Tunable Repetition Rate Multiplier for Optical Phase Code Sequences

We propose a tunable repetition rate multiplier for optical phase code sequences consisting of a temporal grating and a temporal 4-F system. The temporal 4-F imaging preserves the input code words at the output, while the temporal grating multiplies the code rate by an integer being programed via an arbitrary wave generator. A lower bound and an upper bound are, respectively, set for aperture width of involved active elements and dispersion deviation of involved dispersion elements to control output phase distortion. By numerical simulation, an 8-period-long input sequence of individual phase Barker code with 10 ns code chip width and 2-rad peak phase is multiplied from 4 to 16 MHz corresponding to multiplication factor tuned from one to four. The expected phase preserving feature and tunable capacity are validated. Degradations including leaked ripples and envelop fluctuation are successfully controlled by the aperture-width bound and the dispersion-deviation bound, respectively. The proposed multiplier provides a promising potential for multifunctional photonic-aided continuous-wave radars with enhanced agility and adaptability.