OPTICAL ISOLATORS USING BISUBSTITUTED RARE-EARTH IRON-GARNET FILMS

Using Bi-substituted rare-earth iron garnet film, (GdBi)3 (FeAlGa)5O12 or (YbTbBi)3 Fe5O12, grown by liquid phase epitaxy technique, we have fabricated a compact, low cost and high performance optical isolator for near-infrared wavelength region, in comparison with conventional isolator using yttrium iron garnet (YIG) single crystal as Faraday rotator. Typical insertion loss and isolation of developed isolators are 0.6 dB and 35 dB respectively at λ=1.31 μm and the size is 6φ{symbol}×6 mm. The isolators, which could be used in the wavelength range of 1.31 to 1.55 μm, are also fabricated with insertion loss of less than 1.1 dB and isolation of more than 35 dB. © 1990 Chapman and Hall Ltd.