Poling quality evaluation of periodically poled lithium niobate using diffraction method

Abstract

We demonstrated a simple way of evaluating the duty cycle error in periodically polled lithium niobate (PPLN) based on the method of binary phase diffraction grating. To demonstrate this method, -Z face etched PPLN of desired periods were fabricated by the standard electric field poling technique. The etched PPLN was considered as a surface relief binary phase grating. The diffraction patterns were recorded for different spatial locations along the length of the sample. The experimentally observed efficiencies of the diffracted orders were compared with the theoretically calculated values to estimate the duty cycle error.