Unifying optical gain and electro-optical dynamics in Er-doped thin-film lithium niobate platform
Yimeng Wang, Bitao Shen, Bo Wang, Sijie Yang, Liyuan Yao, Ruixuan Chen, Yunhao Zhang, Haoyu Wang, Xuguang Zhang, Peiqi Zhou, Zihan Tao, Luwen Xing, Zhuliang Lin, Yichen Wu, Wencan Li, Dan Sun, Haowen Shu, Xingjun Wang
Abstract
Modulation and amplification are two fundamental processes in optoelectronics. While discrete implementations have achieved widespread success, the challenge of monolithically integrating sufficient gain and electro-optic bandwidth remains a significant barrier, limiting optical systems’ miniaturization and scalability. We unify these two functions in the Er-doped thin-film lithium niobate (Er:TFLN) platform, achieving a record-high internal net gain of 38 dB in a 9.16-cm-long waveguide amplifier. Meanwhile, leveraging the host material’s strong Pockels effect, we realize ultra wide-range electro-optic modulation with a bandwidth of 53 GHz and operation up to 170 GHz, fabricated alongside waveguide amplifiers using a zero-change process. Additionally, we validate this functional fusion through two signal processing scenarios: self-amplified digital signal encoding and pre-amplified broadband radio frequency front-end receiving, demonstrating improved signal recovery quality compared to off-chip gain. The modulation-amplification integration holds broad potential for increasing system complexity and network depth in applications such as optical interconnections, Lidar, and microwave photonics. By unifying ultra-high optical gain and broadband electro-optic dynamics in an Er-doped lithium niobate thin-film platform, the authors demonstrate an exciting monolithic integration of amplification and modulation on a compact photonic chip. This exciting work showcases record performance for on-chip amplifiers while enabling self-amplified 50 Gbps digital encoding and pre-amplified RF front-end signal recovery.