Mode Splitting in ITO-nanocoated Tilted Fiber Bragg Gratings for Vector Twist Measurement

We proposed and demonstrated a method to improve the birefringence of tilted fiber Bragg gratings (TFBGs) via high-refractive-index indium tin oxide (ITO) coatings. Firstly, we find the mode splitting phenomenon in an ITO film-coated TFBG. Numerical results show that the ITO coating can modulate the wavelength separations between two adjacent p- and s-polarized resonances. A cyclic dependency betw...