Patent ID: 9703047
Date: 2017-07-11
CPC Classifications: G02B

Claim:
1. A spot-size converter for coupling light between a first waveguide and a second waveguide respectively supporting a first propogation mode and a second propagation mode having substantially different dimensions, the spot-size converter extending along a longitudinal waveguiding axis and comprising: a lower waveguiding structure having a first end and a second end opposed to the first end of the lower waveguiding structure, the first end of the lower waveguiding structure being coupled to the first waveguide to receive light therefrom or transmit light thereto in the first propagation mode, the lower waveguiding structure being characterized by a first effective refractive index; an upper waveguiding structure having a first end and a second end opposed to the first end of the upper waveguiding structure, wherein the first end of the upper waveguiding structure is coupled to the second waveguide and configured to transmit light thereto or receive light therefrom in the second propagation mode, and wherein the upper waveguiding structure is characterized by a second effective refractive index; and a first plurality of high-index elements disposed within a cladding structure and extending substantially along the waveguiding axis, wherein the first plurality of high-index elements comprise a first array of high-index elements arranged in a first row that is vertically spaced above the first end of the upper waveguiding structure so as to define a coupling region, wherein a crossing of the first effective refractive index and the second effective refractive index occurs, thereby enabling evanescent coupling of light between the lower waveguiding structure and the upper waveguiding structure.