All solid nitroaniline-silica photonic bandgap fiber

Abstract

The realization of a new type of a photonic band gap (PBG) optical fiber based on the infiltration of an endlessly single mode microstructured optical fiber with 2-methyl 4-nitroaniline (MNA) is presented in this work. A commercially available microstructured optical fiber (LMA-10) with single mode operation over a large wavelength range was used for filling its capillaries with molten MNA. The all-solid MNA-silica PBG optical fiber was characterized over a broad range of wavelengths, from the absorption bandgap of the MNA (~450nm) to near infrared, using objective lens light coupling. The transmission spectra obtained revealed three wavelength regimes of particular interest: for short wavelengths (450nm to ~800nm) distinct bandgap guidance was observed, then for a band between 800nm and 1200nm, the composite optical fiber exhibited high losses, and finally for wavelengths longer than 1200nm a gradual increase of the transmitted throughput was measured. That particular guiding behavior is attributed to the high refractive index dispersivity of MNA. The photonic bandgaps amplitude measured for the first regime of light guidance is dependent upon the infiltration conditions and post-infiltration processing of the composite optical fiber. An increase in the strength of the formed bandgaps was observed after annealing the composite optical fiber at a temperature gradient from 110°C to 50°C with a pulling speed lower than 10mm/hr, for assisting crystallization of the infiltrated MNA.