Hollow Core Photonic Bandgap Fiber, 2000nm

Hollow core Photonic Bandgap Fibers guide light in a hollow core, surrounded by a microstructured cladding of air holes and silica.

Since only a small fraction of the light propagates in silica, the effect of material nonlinearities is insignificant and the fibers do not suffer from the same limitations on loss as conventional fibers made from solid material alone.

・< 5% of optical power located in silica
・Gaussian-like fundamental mode
・Can be filled with gas
・Negligible bend loss
・Fresnel reflection of core mode to air <10e-4
・Mode effective index close to unity
・Numerical Aperture ~ 0.2
・Pure silica for good temperature stability