Integration of Eight-Channel Directly Modulated Membrane-Laser Array and SiN AWG Multiplexer on Si

Eight-channel 56-Gbit/s direct four-level pulse-amplitude modulation is demonstrated using a 1.3-mu m wavelength-division-multiplexing (WDM) photonic integrated circuit (PIC) transmitter, consisting of membrane distributed-reflector lasers heterogeneously fabricated on Si and a SiN arrayed-waveguide-grating multiplexer. Direct bonding, epitaxial regrowth, and low-temperature SiN-waveguide fabrication technologies are employed for the integration on Si. Using a nonlinear equalizer, we operated the fabricated WDM PIC transmitter with a low power consumption of 403 fJ/bit for overall 448 Gbit/s signals. The total eightchannel bit-error rate was 2.7 x 10(-3), which is less than the 7%-overhead hard-decision forward-error-correction limit.