Crystal Fibre A/S
Nonlinear Photonic Crystal Fiber
Crystal Fibre designed its highly nonlinear photonic crystal fiber with zero-dispersion wavelength at 1.55 µm to facilitate the evolution from low-bit-rate electro-optical networks to high-bit-rate all-optical networks.
The company, based in Birkerød, Denmark, says that the fiber has a nonlinear coefficient two times that of standard nonlinear fiber and that it has already been demonstrated at the Research Center COM at the Technical University of Denmark in a non- linear optical loop mirror, demultiplexing a bit stream of 160 Gb/s down to 10 Gb/s without electro-optical conversion. The demultiplexer normally operates with 2.5 km of dispersion-shifted step-index fiber, but the photonic crystal fiber enabled operation with only 50 m of fiber, improving stability and saving cost.
The fiber is polarization-maintaining with a birefringence on the same order as standard polarization-maintaining fibers. The microstructures region enables high design flexibility, and both zero-dispersion wavelength and dispersion slope can be designed to fit different applications.
The fiber's applications include 2R regenerators, optical parametric amplifiers, wavelength converters, optical sampling and supercontinuum generation. Supercontinua are useful not only for telecommunications, but also in fields such as spectroscopy and optical coherence tomography, where supercontinuum-generating photonic crystal fibers have been used as broadband light sources in the life sciences. The supercontinuum also can be used for metrology, as the generated frequency comb can be used as an optical clock.