Wavelength-mode pulse interleaver on the silicon photonics platform

We report an 8-channel wavelength-mode optical pulse interleaver on a silicon photonic chip.Wavelength-and mode-division multiplexing techniques are combined to increase the repetition rate of the pulses without adding the complexity of a single dimension.The interleaver uses a cascaded Mach–Zehnder interferometer architecture as a wavelength-division(de)multiplexer,an asymmetric directional coupler as a mode(de)multiplexer,and various lengths of silicon waveguides as delay lines.A pulse sequence with a time interval of 125 ps is implemented with the repetition rate being eight times that of the initial one.The demonstrated wavelength-mode multiplexing approach opens a new route for the generation of high-speed optical pulses.