In this paper, we improve the fabrication procedure of imprint method to obtain low-loss and low-crosstalk GI-core
waveguides: particularly focus on eliminating the bridged structure. We experimentally demonstrate that the GI-core
waveguides fabricated adopting the modified imprinting method show lower loss and lower crosstalk than SI-core
waveguides fabricated using the same material by the same method, even if a slight bridged structure remains.
Furthermore, by applying this method to fabricate perpendicularly crossed waveguides, we also demonstrate that GI-core
waveguides significantly reduce the loss due to the crossings.