HYBRID PHOTONIC CRYSTAL FIBER

摘要

The hybrid photonic crystal fiber comprises a single core (4) having a refractive index (ncore) and surrounded by a cladding (1), the cladding (1) comprising a background material having a refractive index (n1), high index inclusions (2) and low index inclusions (3) embedded in said background material (1); said high index inclusions (2) comprise solid inclusions having a refractive index (n2) that is higher than the refractive index (n1) of the background material (1) and higher than the refractive index (ncore) of the core (4), the difference (n2-ncore) between the refractive index (n2) of said high index solid inclusions and the refractive index (ncore) of the core (4) being preferably not more than 0.05; said low index inclusions (3) have a refractive index (n3) that is lower than the refractive index (ncore) of the core (4); all the high index inclusions (2) form one inner ring (HIR) or two concentric inner rings (HIR1; HIR2) surrounding the core (4), and all the low index inclusions (3) form two or more concentric outer rings (LIR1; LIR2) surrounding said inner ring of high index inclusions (2) or surrounding said two concentric inner rings of high index inclusions (2); an index-guided core mode (TIR mode) exists for wavelengths higher than a wavelength cutoff value ??, that can be between 400nm and 1800nm, and a bandgap guided core mode within the first band gap exists at least at wavelengths lower than said wavelength cutoff value.