2.5%-Δ silica-based athermal arrayed waveguide grating employing spot-size converters based on segmented core

We describe a novel structure for super-high-Δ athermal arrayed waveguide gratings (AWGs) employing spot-size converters based on a segmented core formed in the slab region, to reduce the diffraction loss in resin-filled trenches. This structure requires no depth-tapering process. We demonstrated a compact 16-channel athermal AWG based on the 2.5%-Δ silica waveguides. The excess loss due to athermalization was reduced to 0.9 dB with the proposed structure, whereas the excess loss was 2.4 dB using a conventional one. The measured results of the proposed structure show no degradation of the crosstalk and passband shape.