Polarizing Fibre Facet Gratings with High Modal Reflectance

摘要

The leaky-mode resonant diffraction gratings fabricated in a high-refractive index layer deposited on the facet of an optical fibre can serve as wavelength- and polarization-selective elements in fibre lasers. We predict a modal reflectance peak as high as 86% with a 3 dB spectral bandwidth of about 50 nm and a polarization extinction ratio of 17 dB using a theoretical model based on a 3D FDTD method. Gratings were fabricated by focused ion beam milling. Experimentally measured transmission spectra were compared with numerical simulations adapted to real grating profiles.