Magnetic field rotating-type Faraday polarization controller

We developed a new polarization controller based on the Faraday effect. The transmittance fluctuation was suppressed to less than 0.03 dB by controlling the direction of a magnetic field with a magnitude exceeding the saturation field of Faraday elements. Because it has no mechanical parts, the new polarization controller can perform polarization control with high reproducibility and high-speed polarization control of better than 10/sup 3/ turns/s on a Poincare sphere. The new polarization controller has a rotatory polarization angle setting accuracy of +-5 and a reproducibility of +-0.3 on the Poincare sphere.