Dual Layer Optical Coupling Configuration Between Photonic Integrated Circuit And External Single Mode Optical Fiber

A dual-layer coupling arrangement comprises a first coupling waveguide disposed within a photonic integrated circuit (at a position over an included optical signal waveguide) and a second coupling waveguide disposed above the first coupling waveguide. The first and second coupling waveguides are formed to exhibit splitter configurations that terminate as a pair arms separated by a distance suitable for creating beams that would coincide with a circular mode field of the core region of a coupling optical fiber. The vertical spacing between the first and second coupling waveguides is set so that the pairs of beams exiting from the terminating arms of the coupling waveguides coincide with a circular mode field.