Fully etched grating couplers for atomic layer deposited horizontal slot waveguides

Abstract

Compact broadband grating couplers are designed and studied utilizing Atomic Layer Deposited Horizontal Slot waveguides, with four well-known material layers as the slot. Fabrication process conditions are experimentally studied to obtain more optimized designs. With the precision of the film thickness and refractive index provided by ALD, fabrication of reproducible grating couplers is feasible. An overview of design guidelines regarding the slot size and slot material is provided by 2D Finite Element Method calculations.