Generating 4 $\times$ 20 GHz and 4 $\times$ 40 GHz Pulse Trains From a Single 10-GHz Mode-Locked Laser Using a Tunable Planar Lightwave Circuit

We demonstrate a tunable pulse repetition rate multiplier using a silica-based planar lightwave circuit (PLC). The PLC is a six-stage lattice-form Mach-Zehnder interferometer which can be tuned thermally to generate 20- and 40-GHz output pulse trains from a 10-GHz input. We use a nonlinear optical loop mirror as a wavelength converter to perform intensity-to-field conversion to eliminate pulse-to-pulse phase fluctuations in the higher-rate output pulse trains. Moreover, we use wavelength multicasting (simultaneous wavelength conversion) to generate multiple pulse trains (4 × 20 GHz and 4 × 40 GHz in the example shown here) from a single 10-GHz input.