Generation of amplitude-shift-keying optical signals using silicon microring resonators

We demonstrate the generation of amplitude-shift-keying (ASK) optical signals using a system of parallel microring resonators. By independently modulating two symmetric microring resonators arranged in a Mach-Zehnder configuration, we realize the generation of three levels. The proposed scheme can be extended to any number of logic levels, which effectively increases the data rate of an optical link using slower modulators. Here, we separately utilize thermo-optic and ultrafast all-optical modulation schemes to generate ASK signals on a silicon photonic chip.