Giant Faraday Rotation in Gadolinium Doped Silica Optical Fibers for High Performance Optical Isolators

Silica fibres doped with small (<;1 mol%) concentrations of gadolinium ions have been fabricated and tested in a 1T magnetic field showing a Faraday rotation two orders of magnitude larger than that reported in conventional telecom fibres. This is the largest Faraday rotation ever reported in low-loss optical fibers and could pave the way for a new class of optical isolators.