Integrated Lithium Niobate Photonics for Millimeter-wave Applications

Description

By 2022, the data to and from wireless devices will account for 63% of the total global internet traffic. This ever-growing bandwidth requirement can only be met by shifting the communication channel frequencies towards higher-frequency, millimeter-wave (MMW) bands (30-300 GHz). This largely unexplored spectrum could provide unprecedented data bandwidths for 5G and beyond, allowing for data rates orders of magnitude higher than current networks.At MMW frequencies, however, the underlying electronic components become increasingly expensive, inefficient and lossy due to the gain-bandwidth trade-offs and the exacerbated cable losses. In recent years, photonic approaches have emerged as a promising candidate for future MMW signal transmission and processing units because of the intrinsic low-loss nature of light and the availability of the mature telecommunication infrastructure. However, conventional optical components are typically large in size and limited to bandwidths of ~ 35 GHz, preventing them from direct co-integration with MMW systems.This project aims to develop an integrated photonic-MMW platform that is ideally suited for future compact, low-cost MMW systems. The key component proposed is an integrated MMW modulator that can efficiently and faithfully convert MMW signals up to 300 GHz into optical domain. The MMW modulator is based on a sub-micrometer-thick lithium-niobate (LiNbO3, LN) layer, which offers significantly stronger optical confinement and more efficient electrooptic modulation than traditional ion-diffusion based LN modulators. PI is an expert in integrated LN photonics and has previously demonstrated integrated LN modulators that can operate at low powers and high speeds, promising for next-generation telecommunication and datacenter applications (C. Wang et al., Nature 2018). In order to further push the modulator bandwidths to cover the entire MMW range, this project will involve innovative co-design of integrated LN photonics and MMW transmission lines on the same photonic-MMW chip. In addition to the core component, this project will develop a set of advanced photonic-MMW components, including linearized modulators and integrable MMW receiving antennas. PI will work closely with Collaborator, who has more than 30 years of experience in microwave engineering, and leverage the MMW and photonic infrastructure and expertise available at CityU to ensure the successful delivery of the project.The successful accomplishment of this project will create an ultra-compact, full-fledged MMW package that could enable a range of applications including 5G communications, medical imaging, machine vision and remote sensing, and could benefit the broad academic and industrial communities both in Hong Kong and across the globe.