Wavelength-Division Multiplexing on an Etchless Lithium Niobate Integrated Platform
Yue Yu, Zejie Yu, Zunyue Zhang, Hon Ki Tsang, Xiankai Sun
Abstract
Arrayed waveguide gratings (AWGs) are widely used as (de)multiplexers in wavelength-division-multiplexed optical communication systems and as integrated spectrometers in optical sensing and imaging systems. Lithium niobate integrated photonics is a burgeoning field due to many excellent optical properties of lithium niobate and rapid development of wafer processing technologies. Here, we introduced a new strategy of low-loss waveguiding on an etchless lithium niobate integrated platform for realizing high-performance AWGs thereon. We experimentally demonstrated 4-, 8-, and 16-channel AWGs operating in both telecom and near-visible wavelength bands on the etchless lithium-niobate-on-insulator platform. All the channels have insertion losses below 9.1 dB and crosstalks less than −12.8 dB in the designed wavelength bands. With advantages of an ultrawide transparency window and strong electro-optic and nonlinear optical coefficients of lithium niobate, the demonstrated AWGs will find wide applications in on-chip high-capacity optical interconnects, ultrafast bioimaging, LiDAR, and astronomical spectrographs.