A Garnet Based Optical Isolator for 0.8 µm Wavelength

Highly bismuth substituted garnet films with low optical absorption are required to achieve acceptable performance levels of <3dB insertion loss and >30 dB isolation in the 0.8 um wavelength region. A prototype optical isolator device was fabricated which has 2.7 dB insertion loss and 35dB isolation at 0.786 um. We have prepared bismuth substituted rare-earth iron garnet films (BRIG) with 0.8 Bi/formula in a configuration in which garnet antireflection (AR) layers were included to minimize loss and backreflections from the isolator. We have also prepared single layer, single sided films with 1.3, 1.9, 2.1 and 2.3 Bi/formula.