KTN optical waveguide devices with an extremely large electro-optic effect

KTa1-xNbxO3 crystal exhibits an extremely large quadratic electro-optic effect, which is 20 times greater than that of LiNbO3. This property makes this crystal attractive for optical signal processing applications. We have successfully prepared a 2-inch KTN crystal that exhibits the largest quadratic electro-optic coefficient ever reported. We have also fabricated a buried optical waveguide with a low transmission loss and demonstrated an optical switch with a driving voltage of 2.6 V and a 92 nsec rise time. This paper reviews the crystal growth, material properties, electro-optic effect, waveguide fabrication, and optical switch operation of KTN crystal.