High-Quality Polarization-Insensitive Polysiloxane Waveguide Gratings Produced by UV Nanoimprint Lithography

We describe the fabrication of single-mode polarization-insensitive polysiloxane channel waveguide gratings by a single-step ultraviolet nanoimprint lithography process with a polydimethylsiloxane stamp. A 10-dB deep grating response that matches the theoretically expected response at the first-order resonant wavelength was achieved in a 2-mm-long grating with no excess loss over the intrinsic material absorption. Features down to ~100 nm could be replicated using the soft stamp.