Polarization non dependence die optical aisore - ta

摘要

PURPOSE:To enable the optical isolator to have wide-range temperature and wide-range wavelength so that two Faraday rotators compensate temperature and wavelength characteristics mutually by setting the magnetism directions of the two Faraday rotators opposite each other for the optical isolator. CONSTITUTION:When unpolarized light is made incident, the light is split by a 1st birefringent crystal plate 6 into an ordinary light beam and an extraordinary light beam, a 1st Faraday rotator 8 rotates the planes of polarization by 45 deg., and the light beams are distributed to three-division polarizing plates 5-1 - 5-2 respectively. Then the light after being transmitted enters a 2nd Faraday rotator 9 whose magnetism direction is opposite and has the plane of polarization reversed by 45 deg. to enter the original polarized state, and the light is made incident on a 2nd birefringent crystal plate 7. At this time, the 1st and 2nd birefringent crystal plates 6 and 7 are arranged symmetrically about a plane and then the ordinary light and extraordinary light are coupled with a port 2 regardless of polarization. Return light is absorbed and eliminated by the three-division polarizing plates 5-1 and 5-2. Consequently, the price is made low and the system is reducible in size.