Programmable Fiber-Optics Pulse Repetition-Rate Multiplier

We develop a strikingly simple fiber-optics pulse repetition-rate multiplication approach, based on dispersion-induced temporal self-imaging (TSI) effect, in which the rate multiplication factor can be electrically programmed to be any desired integer value. The multiplier setup is composed of an electrooptic phase modulator followed by a dispersive medium. In contrast to the conventional TSI-based rate-multiplication techniques, the required dispersion is fixed in this method and does not depend on the multiplication factor. Programming the output repetition rate will be then assigned to a preprocessing step where the overall phase of the input pulses is modulated by a phase modulator. Herein, we derive in detail a condition for the required dispersion and introduce an analytical equation for the temporal phase modulation. To validate the derived expressions, proof-of-concept experiments have been carried out and we have achieved high-quality tunable rate multiplication, by factors ranging from 1 to 4, of mode-locked fiber lasers with input repetition rates of 10 and 4.85 GHz, respectively.