Corrugation-Induced SiO $_{2}$ Planar Long-Period Gratings for Photonic Applications

A long-period grating based on silica planar lightwave circuit technology is reported. The grating structure has been realized by forming a periodic corrugation on the lower waveguide cladding layer. This structure offers a permanent refractive index modulation, resulting in a grating that is highly stable to environmental variation. A strong rejection band is observed at a specified resonance wavelength. Device sensitivity to external refractive index change of up to 2.9 × 10^-6/pm can be achieved without any surface modification. Thermal characterization has demonstrated a temperature dependence of only 24.5 pm/°C .