Recent advance of over 400-Gb/s per lane modulator PIC

Optical modulator PIC operating over net-400 Gb/s/lane will be an essential component for next generation 3.2-T Ethernets driven by the rapid growth in intra-data centers. In this work, we review the current status and development for the 400-Gbps signals per lane (400G/lane) optical modulator technologies. For minimizing device size and power consumption, we particularly focused on developments of O-band InP-based Mach–Zehnder modulator (MZM) PIC which doesn’t require Thermo-electric cooler (TEC) control. By combining a low-electrical-loss n-i-p-n heterostructure with a capacitive-loaded traveling-wave electrode (CL-TWE), the device achieves 100-GHz-class bandwidth and operations with a low-driving voltage of 2.0-V Vπ. It is capable of CMOS direct drive, eliminating the need for an external driver IC. We also fabricated the 8-lane differential drive MZMs array in which a dual 1×4 waveguide configuration with two optical input ports was integrated on the PIC die. The PIC exhibited net 3.2-Tb/s (400G/lane) 500 m transmission over the temperature range of 20 to 80°C. The high-speed and high-performance PIC with low-power driving will be a key for the next-generation 3.2-T and beyond transceivers.