Anomalous dispersion in Lithium Niobate one-dimensional waveguide array in the near-infrared wavelength range

TL;DR

This paper investigates the dispersion properties of Lithium Niobate waveguide arrays in the near-infrared, revealing how decreasing array period transitions the system from normal to anomalous dispersion, with implications for optical data processing.

Contribution

It introduces two methods to analyze dispersion in LiNbO3 waveguide arrays and demonstrates the transition from normal to anomalous dispersion as array period decreases.

Findings

Transition from normal to anomalous dispersion with decreasing array period

Achromatic point observed in dispersion behavior

Feasible parameters for optical data processing applications

Abstract

Knowing the dispersion regime (normal vs anomalous) is important for both an isolated waveguide and a waveguide array. We investigate by the Finite Element Method the dispersion properties of a LiNbO3 waveguides array using two techniques. The first one assumes the Coupled Mode Theory in a 2-waveguide system. The other one uses the actual diffraction curve determined in a 7-waveguide system. In both approaches we find that by decreasing the array period, one passes from normal dispersion by achromatic point to anomalous array dispersion. We then illustrate the wavelength separation by doing Runge-Kutta light propagation simulations in waveguide array. As all the parameters values are technologically feasible, this opens new possibilities for optical data processing.