Solid-core Photonic Band-Gap Fiber with Polymer Coating for Biosensing Applications

摘要

In order to achieve photonic band-gap effect as sensing mechanism and improve biocompatibility of relatively lower-cost silica-core phonic crystal fibers (SCPCF) and make use of photonic band-gap effect as sensing mechanism, polymer with similar biocompatibility as PMMA coating in SCPCF air-holes is proposed in this paper. In order to evaluate the polymer coating effect, a three-layer model of air hole is proposed. The wavelength shifts of photonic band-gap edges (PBEs) were evaluated by plane wave expansion (PWE) method, assuming refractive index of silica n_s, , polymer n_p and air n_a are 1.45, 1.50 and 1.00 respectively. Blue shifting of bands are observed in the simulation and the bandwidth of each band-gap becomes narrower with the increasing of air ratio. The result shows that 1nm change of air hole is able to obtain a wavelength shift of 0.43nm. Assuming the wavelength shift of 0.01nm can be detected, a small air hole variation of 0.023nm can be measured.