Arbitrary repetition-rate control of periodic optical pulse trains based on a phase modulator cascaded with an optical tapped delay line structure

We propose a novel method to achieve arbitrary repetition-rate control of periodic optical pulse train. The scheme is based on the combination of a phase modulator (PM) and an optical tapped delay line (OTDL) structure. The PM is utilized to adjust the start point of input pulse train on the Talbot carpet. We theoretically derive the corresponding relation between the dispersion amount and the OTDL structure in performing temporal Talbot effect. According to the relation, the OTDL structure is designed to provide equivalent dispersion amount that repetition-rate multiplication or division requires. Through proper selection of the start point and destination on the Talbot carpet, we can realize arbitrary control of optical pulse trains’ repetition-rate, including integer repetition-rate multiplication, fractional repetition-rate multiplication, integer repetition-rate division and fractional repetition-rate division. Several numerical simulations have been performed and the results are in accordance with theoretical analysis. The effects of delay deviation and phase deviation of the OTDL structure on the output optical pulse train have also been discussed.