Optical waveguide dispersion control device for nonlinear process and its design method

Abstract

The invention proposes an optical waveguide dispersion regulating device and a design method thereof for nonlinear processes. By dividing the optical waveguide into several waveguides whose widths vary periodically, broadband phase matching under the control of multiple degrees of freedom can be realized. First, the relationship between the wave vector mismatch of light participating in the second-order nonlinear process and the waveguide width is obtained through numerical simulation. According to the overall planning, the width and length of each waveguide can be optimized through an optimization algorithm. Calculate the amount of phase mismatch brought by each section, and make the phase difference introduced by each section of the waveguide cancel each other within an optimized nonlinear period, obtain a flat phase difference spectrum, and finally make the average of the nonlinear process in the wavelength range of interest The wave vector difference is close to 0, thereby realizing nonlinear phase matching with large bandwidth. The invention can further improve the bandwidth of the phase matching while ensuring the existence of the phase matching working point in the integrated optical waveguide.

Description

technical field [0001] The invention relates to an optical waveguide dispersion control device used in a nonlinear process and a design method thereof, belonging to the field of optical nonlinear technology. Background technique [0002] Optical nonlinear processes are widely used in the generation of optical signals. In this way, the frequency of lasers can be greatly extended at low cost, especially to achieve long-span wavelength conversion. To realize the optical nonlinear process, the participating optical signals must satisfy the two conditions of energy conservation and phase matching at the same time. However, since phase matching is limited by dispersion, it is difficult to satisfy these two conditions simultaneously. One way to solve this problem is to use quasi-phase matching, which introduces wave vector perturbation by periodically poling lithium niobate crystal materials to compensate for the wave vector mismatch between the light participating in the nonlinea...

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Problems solved by technology

However, this method does not guarantee the generation of phase matching points, and even if it does, its tolerance to the working wavelength is very low, and a small wavelength shift will cause a huge change in the phase mismatch, which limits the nonlinear bandwidth in the process

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