Hybrid silica/polymer long period gratings for wavelength filtering and power distribution

We report long period grating (LPG) devices based on a hybrid architecture incorporating photopatternable fluorinated poly(aryl ether ketone) and silica layers for applications in wavelength filtering and power distribution. The grating structure was implemented using a periodic corrugation on a thermally oxidized silica lower cladding layer, a photopatterned fluorinated polymer ridge waveguide, and a similar polymer top cladding. In this design, the corrugated silica layer allows a highly stable grating structure, while the fluorinated polymer offers a low propagation loss and easy processability. Strong rejection bands have been demonstrated in the C+L wavelength band, in good agreement with theoretical calculations. The fabricated LPG devices show a thermal dependence of 1.5 nm/ degrees C. Based on this design, an array of waveguides incorporating LPGs has also been fabricated. Distribution of light at the resonance wavelength across all the channels from a single input has been demonstrated. These results are promising for power distribution in photonic network applications or on-chip sensors.