Rare earth-implanted lithium niobate: Properties and on-chip integration

We investigated the optical properties of rare-earth ions (Yb3+ and Er3+) implanted into lithium niobate (LN) crystals and observed superluminescent emission from a sheet of Yb ions in the Yb-implanted LN crystal (Yb:LN). Moreover, by directly integrating the Er-implanted LN crystal (Er:LN) with a silicon photonic chip with waveguide and resonator structures, we observed the evanescent coupling of photoluminescent light from the Er ions to the optical modes of the waveguide and microcavity. We measured an optical quality factor of about 104 and observed a modification of the photoluminescent emission from Er3+ ions in the integrated structure. The platform can ultimately enable developing the integrated multifunctional quantum photonic devices.