Frequency Conversion Based On Periodically Poled Lithium Niobate Waveguide

Quasi-phase-matching (QPM) is a technique for phase matching nonlinear optical interactions which the nonlinear coefficient is modulated spatially at regular intervals using a structural periodically built into the nonlinear medium. A higher nonlinear frequency conversion efficiency can be obtained and a wider wave-band application of the material can be realized through QPM. LiNb03 is one of the perfect materials to achieve the QPM and develops rapidly because of its character of high effective nonlinear coefficient. The development of PPLN fabrication and its electronic poling technique contribute to the application research on PPLN in nonlinear frequency conversion become hot recently.This dissertation discusses theoretically the principle of QPM as well as the method to achieve QPM technology. We deduce the QPM second-order nonlinear coupling wave equation based on periodically structure in detail, and obtain the frequency conversion efficiency. The results indicate that QPM provides periodically spatial modulation to the second order nonlinear coefficient and the high frequency conversion efficiency is attributed to the highest nonlinear coefficient. The characteristic of annealing proton exchanged PPLN waveguide is described. The room temperature poling on LiNbO3 crystal by high voltage pulse power is realized successfully, and the principle of electronic periodically poled domain conversion is also investigated.We experimentally know the normalized SHG frequency conversion efficiency is 75% /W ?1 ? cm?2. The experimental principle of all-optical wavelength conversion through the cascaded second-order nonlinear processes in PPLN waveguide is presented in brief . We also give the theory of guide-wave QPM optical frequency conversion, and get some significant results which will be beneficial to the next study on wavelength conversion devices based on QPM PPLN waveguide.