Integrated Hybrid Wavelength-Tunable III–V/Silicon Transmitter Based on a Ring-Assisted Mach–Zehnder Interferometer Modulator

We demonstrate a wavelength-tunable hybrid III-V/Si transmitter based on a Vernier laser with more than 30 nm tuning range and two microring modulators nested in a Mach-Zehnder interferometer. This transmitter circuit has versatile operating modes. It can be used for on-off keying (OOK) generation based on low drive voltage push-pull ring modulators and for quadrature phase-shift keying (QPSK) generation where binary phase-shift keying signal is generated by each ring. We reported the first hybrid III-V/Si integrated wavelength-tunable transmitter based on high-speed ring modulators (BW ~23 GHz), which can cover more than 30 nm. OOK signal generation with better signal integrity, lower drive voltage, and lower chirp is demonstrated as well as 80 Gbit/s polarization-division multiplexing QPSK signal transmission over 100 km with the integrated hybrid transmitter and a fully packaged silicon-based coherent receiver.