Polymeric optical mode converter for hybrid photonic integrated circuits
A mode converter design for hybrid PICs based on silicon mounting block and polymeric optical waveguides are presented. Fabrication involves silicon structuring based on diffusion limited etching and flexible coating properties of polymers. Using the proposed process, mode converters can be created for low loss coupling from arrays of singlemode fibers to strongly confined, large index difference waveguide, and further to semiconductor components. Simulations of the mode converters show a theoretical lower loss limit due to mode mismatch of -0.21dB for fiber to waveguide coupling, while down-tapering to a 1.5 μm × 1.5 μm large index difference waveguide has a conversion loss of -0.15dB.