Photonic molecules stacked on multicore optical fiber for vapor sensing

Abstract

We designed and fabricated photonic molecules on the tiny end facet of a multicore optical fiber. The photonic molecules are three pairs of coupled polymer micro-ring resonators, which are stacked on the fiber in three layers. The normal mode splitting of the photonic molecules is simulated and observed experimentally. It is shown that if the absorption of vapors causes both the radii and refractive index changes of the rings, the two branches of the split resonant modes show different wavelength shifts. The photonic molecules were fabricated by the two-photon lithography technology and show good sensitivity to various organic vapors.