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.