Contents 1. Introduction
Si photonic integrated circuits (PICs) with transceiver functionality is the emerging technology for new-era data centers toward 0.4-3.2 Tbit/s in the future. This development strictly relies on designing and fabricating the Si waveguide intensity modulator with an encodable data rate beyond 50 Gbit/s per channel. To meet this demand, in 2021, Lee et al. performed the single-arm-driven Si-MZM with low power consumption at C-band (λ =1550 nm) for NRZ-OOK encoding beyond 50 Gbit/s over 10-km single-mode fiber (SMF). [1]. Nevertheless, the driven temperature and voltage dependency of such a Si-MZM operated at free-carrier-depletion case always vary with changing data amplitude, which needs to be precisely controlled for stabilizing its optimized parameters for long-term operation. In this work, the phenomenon of the data-amplitude-dependent shift of the power-to-voltage response with reduced on/off extinction ratio is observed for the uncooled Si-MZM,which needs to be pre-compensated via offsetting the DC bias of the Si-MZM from its originally condition optimized without encoding data stream. This observation declares the effect of driven data amplitude on the encoding performances in terms of characteristic parameters such as modulation output efficiency, SNR, ER, and BER for the Si-MZM encoded with NRZ-OOK at 60 Gbit/s or beyond.
