Photonic chips go 3D: NIST stacks tantala on lithium niobate for all-in-one nonlinear optics

NIST researchers just published the first monolithic 3D photonic platform — 570 nm of tantala deposited directly on 300 nm thin-film lithium niobate — and it handles OPO, microcombs, SHG and interlayer routing on a single chip. 10,000 programmable-color circuits per die, 50 dies per wafer.