Optical waveguide isolator based on nonreciprocal loss/gain of amplifier covered by ferromagnetic layer

The effect of nonreciprocal loss/gain of a waveguide optical amplifier covered by an absorbing magnetooptic layer was studied for the first time, it is shown that the optical loss/gain of this amplifier differs for the forward and backward propagation when the magnetization is perpendicular to the light propagation and lies in the film plane. Using this effect a new design of an optical isolator is proposed, which is beneficial for monolithic integration of the optical isolator with a laser diode. A calculation predicts an isolation ratio as high as 180 dB/cm for GaAs/sub 1-x/P/sub x/-Al/sub 1-x/Ga/sub x/As optical amplifier covered by a Co layer.