Thermal annealing of magneto-optical (Cd,Mn)Te waveguide for wider operation wavelength range of optical isolator

Several Cd/sub 1-x/Mn/sub x/Te (x = 0.225) core waveguides with graded-refractive-index (x = 0.225 - 0.26) layers are grown at 300/spl deg/C by molecular beam epitaxy (MBE) and annealed in the MBE chamber at different temperatures between 400/spl deg/C and 450/spl deg/C for 5 min. The post-growth annealing results in a wider wavelength range (between 710 nm and 735 nm) of the complete mode conversion ratio of the waveguides. The low optical propagation loss, high magneto-optical figure of merit and an isolation effect of annealed waveguides are also examined. The results of this experiment demonstrate the feasibility of (Cd,Mn)Te waveguide for the practical waveguide optical isolator.