Abstract

Lithium niobate (LN) is one of basic materials of integrated optics used, for example, for electro and acousto-optical modulators, switches, diffraction gratings, nonlinear optical wavelength converters, and others [1]. LN-based ion exchange or Ti-indiffused photolithographic techniques are established technologies, however, some modern applications, such as high-purity suppressed carrier synthesis or high extinction ratio pulse generation for precision measurement systems require the use of additional active trimming electrodes [2] and a corresponding servo loop because of finite tolerances of optical elements. Recently developed direct laser writing (DLW) with femtosecond/ultrafast laser pulses [3] can be employed to address the problem, but this method is problematic for mass production and suffer from high insertion loss in optical waveguides (typically ~ 1 dB/cm compared to <0.1 dB/cm for Ti-indiffused waveguides).

© 2017 IEEE