Crystal growth of a highly Bi-substituted gadolinium iron garnet and its application to an 0.8 .MU.m optical isolator.

Single crystals of highly Bi-substituted gadolinium iron garnets have been grown by an improved flux method in which Bi2O3, is used as a flux. Faraday rotation and optical absorption are measured in the near-infrared region at room temperature. The magnetooptical figure of merit is 44deg/dB at 0.78μm in Gd1.8Bi1.2Fe5O12. A very compact optical isolator has been developed for 0.8μm wavelength by using this crystal as a Faraday rotator. The optical isolator features 1.5dB insertion loss and 32 dB backward loss at wavelength of 0.78μm.