Wide-aperture Faraday isolatorfor kilowatt average radiation powers

A Faraday isolator with an aperture of 20 mm and compensation of thermally induced polarisation and phase distortions of laser radiation is fabricated and tested experimentally. A considerable improvement in the isolation degree over a traditional Faraday isolator is demonstrated. For radiation power up to 750 W, the isolation degree lies in the range 24 – 26 dB and is limited only by the quality of TGG crystals.