Wafer-scale low-loss lithium niobate photonic integrated circuits

To date, monolithic thin-film lithium niobate pho-tonic integrated circuits (LN PICs) have been limited to chip-scale proof-of-concepts. We fabricate LN PICs on 4- and 6-inch wafers with deep ultraviolet lithography and show smooth and uniform etching. We achieve 0.27 dB/cm optical propagation loss on wafer-scale.