Refractive Index Profiles of Copper Ion Exchange Glass Planar Waveguides

Glass planar optical waveguides are fabricated by the copper ion-exchange technique.The refractive index(RI)profiles of waveguides are reconstructed by the inverse Wentzel–Kramers–Brillouin(IWKB)method.Cu^(+)and Cu^(2+)ion concentrations are calculated by solving the diffusion equation,and the mechanism of RI changes is analyzed.The model between the RI and ion concentrations is proposed by taking both Cu^(+)and Cu^(2+)into account,according to polarizability changes among Cu^(+),Cu^(2+)and Na+.The results show that the contribution of Cu^(2+)is not negligible,and the reason for the RI change is of Cu^(+)and Cu^(2+).With the exchange time increasing,the redox process between Cu^(+)and Cu^(2+)will play an important role on RI profiles.