| All-optical wavelength conversion based on aperiodically poled Li Nb O3(PPLN) crystal is researched in this paper. And the effect of temperature on the structural design of the segmented PPLN crystal based wavelength converter is analyzed.Firstly, the model of uniform segments PPLN structure is established, and the process of hybrid genetic algorithm for structural optimization design is presented. We present an effective hybrid GA, which includes such techniques as establishing a population, clustering, sharing, crowding, adaptive genetic operators, elitist replacement, and fitness scaling. This hybrid GA can effectively solve the problem of finding the optimal value, and significantly shorten the simulation time.Then we analysised the impact of the segment number and crystal lengthon the wavelength conversion characteristics, such as conversion bandwidth, efficiency and flatness.Secondly, the model of ladder segments PPLN structure is established. Wavelength conversion characteristics based on ladder segments PPLN crystal and DFG is researched. When the crystal length unchanged, increased by the number of ladder sections, rational design the initial parameters of the polarization cycle segment the change amount of step between adjacent segments, while the high flatness, a large bandwidth and high conversion efficiency can be obtained.Finally, under the factors of conversion efficiency, flatness, conversion bandwidth and temperature, the paper studys the effect of temperature changes on the structure optimization segment PPLN crystal structure design. We obtain the optimal polarization cycle 25℃~250℃ segmented architecture PPLN crystal with temperature variation, and the corresponding wavelength conversion characteristic temperature. |
PDF Full Text Request