Light-Induced Array of Three-Dimensional Waveguides in LithiumNiobate by Employing Two-Beam Interference Field

Abstract

We propose a novel approach to fabricate an array of three-dimensionalwaveguides in lithium niobate by employing illuminations of a pair ofmutually coherent or incoherent two-beam interference patterns.Adjusting periods of the patterns and the angle between the gratingvectors of the two patterns, we find that arrays of square, rectangularor parallelogrammic waveguides can be created. An array of rectangularwaveguides is demonstrated in an iron doped lithium niobate by the doubleexposures of two-beam interference patterns with differentorientations. The measured index distribution and the guiding testresults show that the waveguide array is successfully fabricated.