Fabrication of polymer optical waveguides with integrated micromirrors for out-of-plane surface normal optical interconnects

In this communication, the fabrication and characterization results of O/E-PWBs comprising multimode polymer waveguides with optical-I/O-coupling facets are presented. The epoxy-based glycidyl ether derivative of bisphenol-A novolac (SU-8) and its refractive index modified grade (L6100) polymers are used as the optical waveguide core and the cladding, respectively. The waveguides with integrated 45° out-of-plane turning micromirrors are fabricated using ultraviolet (UV) lithography. The surface topography and sloping angle characterization using scanning electron microscopy (SEM) showed that 45-degree nearly rectilinear mirror planes were achieved. Parallel waveguide channels with the total-internal-reflection (TIR) are fabricated as an optical-build-up layer on conventional PWBs for functional evaluation. The waveguide transmission loss of the guides with and without the mirror facets is measured using the cut-hack method.