Electrooptically wavelength-tunable polarization converter utilizing strain-optic effect on X-cut LiNbO3

A new electrooptically wavelength-tunable polarization converter by strain-optic effect on LiNbO₃ is presented. The polarization conversion is achieved by the tilt of waveguide principal axis caused by the stress induced by the proton-exchanged region on the single side of the waveguide. Simply increasing the proton-exchange time can enlarge the stress-distributed region and its interaction with the input light, thus, the conversion efficiency can be enhanced. By electrooptic effect, the wavelength of maximum conversion can be tuned at a rate of 0.081 nm/V with a maximum conversion efficiency of 92.4%.