Magneto-optical elements shortening - the way towards Faraday isolators for high average laser power

In this paper we discuss an approach to decreasing the thermally induced depolarization which consists in shortening the magneto-optical elements of Faraday isolators themselves. As long as it is essential for proper operation of isolators to keep the angle of rotation of the polarization plane unchanged and equal to 45deg during one pass through the device, this shortening was provided by increasing the magnetic field. In turn, the magnetic field increasing may be achieved either by using magnet systems based on superconducting solenoids or by optimization of the magnet field of permanent magnets.