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 ~4900 nm/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 ~10(-7). Such high resolution sensors enable detection of minute changes with potential applications to various biochemical industries.

Tunable wavelength filters using polymer long-period waveguide gratings based on metal-cladding directly defined technique

“…Long-period waveguide gratings (LPWGs) are gratings in planar waveguide with grating period around 100 µm. [1][2][3] LPWGs-based devices have aroused considerable interest in recent years in the field of optical communication and sensor application because of the flexibility in waveguide structure and material as compared with the long-period fiber gratings. [4][5][6][7][8] Specially, LPWGs-based tunable wavelength filters are very suitable for realizing functional wavelength division multiplexing systems using optical planar integrated circuits.…”