Improved design of magnetooptic rib waveguides for optical isolators

Garnet films of the following compositions (Lu,Bi)/sub 3/(Fe,Ga,Al)/sub 5/O/sub 12/ and (Tm,Bi)/sub 3/(Fe,Ga)/sub 5/O/sub 12/ are grown by liquid-phase epitaxy on [111]-oriented substrates of gadolinium gallium garnet. Double layers with opposite signs of Faraday rotation and single layers are prepared. Optical monomode rib waveguides are realized using such films. The nonreciprocal phase shift of the fundamental TM-mode is studied both theoretically and experimentally at a wavelength of 1.3 /spl mu/m. The maximum nonreciprocal effect of double layer films is about 1.7 times larger than that of similar single layer waveguides. Agreement between experiments and calculations is excellent.