Reduction of Second-Order Temperature Dependence of Silica-Based Athermal AWG by Using Two Resin-Filled Grooves

We devise a novel design for an athermal silica-based arrayed-waveguide grating (AWG) to reduce the residual second-order temperature dependence of conventional athermal AWGs with a silicone-filled groove. This athermal AWG has two grooves filled with silicone and polyolefin that compensate for the first- and second-order temperature dependence, respectively. The passband wavelength variation is successfully reduced from 80 to 16 pm in a -40°C ~ +80°C temperature range.