Ultra-compact lithium niobate photonic chip for high-capacity and energy-efficient wavelength-division-multiplexing transmitters
Hongxuan Liu, Bingcheng Pan, Yishu Huang, Jianghao He, Ming Zhang, Zejie Yu, Liu Liu, Yaocheng Shi, Daoxin Dai
Abstract
Recently, high-performance thin-film lithium niobate optical modulators have emerged that, together with advanced multiplexing technologies, are highly expected to satisfy the ever-growing demand for high-capacity optical interconnects utilizing multiple channels.Accordingly, in this study, a compact lithium-niobate-on-insulator (LNOI) photonic chip was adopted to establish four-channel wavelength-division-multiplexing (WDM) transmitters, comprising four optical modulators based on ultracompact 2 2 Fabry-Perot cavities and a four-channel WDM filter based on multimode waveguide gratings.The fabricated chip with four wavelength channels has a total footprint as compact as 0.3 2.8 mm 2 , and exhibits an excess loss of ~0.8 dB as well as low inter-channel crosstalk of < -22 dB.Using this LNOI photonic chip, high-capacity data transmissions of 320 Gbps (4 80 Gbps) on-offkeying signals and 400 Gbps (4 100 Gbps) four-level pulse amplitude signals were successfully realized with the ultra-low power consumption of 11.9 fJ/bit.