“…The structural uniformity of cubic KTN might also overcome the polarization dependence. Since the 1960s, many studies have been undertaken on KTN crystal growth [3][4][5] and liquid phase epitaxy (LPE) [6][7][8], although no devices have been realized. In this paper, we report the establishment of bulk crystal growth technology leading to practical substrates and film growth technology for use in fabricating optical waveguide devices.…”