Measurement of optical nonreciprocal phase shift in a bi-substituted Gd3Fe5O12film and application to waveguide-type optical circulator

An waveguide-type optical circulator can be constructed with an optical nonreciprocal phase shifter and 3-dB directional couplers. We have measured nonreciprocal phase shift in a Bi-substituted Gd
3
Fe
5
O
12
(abbreviated as Bi:GdIG) thin film. It is shown that the optical circulator of several millimeters length can be realized by using Bi:GdIG.