Polarization-based refractive index sensor using dual asymmetric long-period gratings in ridge waveguides

Abstract

We propose a sensor scheme operating in the wavelength band of 1460–1530 nm (S band) that utilizes two orthogonally polarized eigenmodes in a ridge-waveguide geometry by employing a pair of nonidentical asymmetric long-period gratings. Numerical simulations show a high sensitivity $\sim 4900\mathrm{nm}/\mathrm{RIU}$ (refractive index unit) over the refractive index range 1.33–1.34 exhibiting a relative resonance shift of 1 pm for an index change of $\sim {10}^{-7}$. Such high resolution sensors enable detection of minute changes with potential applications to various biochemical industries.

© 2013 Optical Society of America