Design of silica-based photonic crystal fiber for biosensing applications

In this paper, the design of a new photonic crystal fiber sensor for methadone detection in water is reported. The sensor feasibility is numerically demonstrated via accurate simulations performed by employing a Finite Element Method (FEM) numerical code. The fiber cross section, including a polymeric cladding as sensitive layer, is optimized. In particular, the sensor refinement is obtained via a large number of simulations performed by varying the thickness of the polymeric layer, the hole diameter, the hole-to-hole spacing and the transversal distribution of the holes. The simulation results suggest that a suitable fiber cross section design can enhance the evanescent field interaction with the polymeric layer permeated by the analyte.