Hybrid integrated optical device enabling high tolerance optical chip bonding and the method to make the same

Abstract

An optical device includes an optical bench and two flip-chip bonded optical chips. The optical bench includes a large area slab waveguide structure which has an input facet facing the first optical chip, an output facet facing the second optical chip, and one or more curved facet which reflects the slab mode light such that the input optical mode coupled through the input facet diverges in the slab waveguide plane as it propagates, reflects at the one or more curved facets, and focuses to an output optical mode at the output facet with mode size larger than the input optical mode in the in-plane direction. During fabrication, after the first optical chip is flip-chip bonded, the location of the focused output optical mode on the output facet is determined, and then the second optical chip is flip-chip bonded based on the determined location of the output optical mode.