Referring to FIG. 7, there is a graph illustrating a fundamental mode 702 having an evanescent tail extending in the superstrate 103 of a traditional GCW that has a substrate 112 made from cyclic-oflefin copolymer (COC) (index nS=1.53), a waveguide film 106 made from Ta2O5 (index nf=2.01) and a superstrate 103 containing H2O (index nc=1.33).