Research On Temperature Characteristics Of Aperiodic Poled LiNbO₃ Based All-optical Wavelength Conversion

With the development of optical fiber communication technology,the demand for high-speed and large-capacity communication services is increasing,as well as the all optical network(AON).All-optical wavelength conversion is the key technology to realize AON,which can effectively avoid path blockage and improve communication efficiency.Therefore,research on all-optical wavelength conversion technology is of great significance.In this paper,the ultra-wideband wavelength conversion technology based on aperiodic quasi-phase matching structure,mainly segmented grating structure,is studied.By deeply analyzing the wavelength conversion mechanism of periodically polarized lithium niobate(PPLN)based on segmented grating structure,and using the wavelength conversion scheme based on cascaded second-order effect,a mathematical model suitable for fast matrix calculation is established.In the mathematical model,the fast matrix algorithm for the coupled mode equations of cascaded second harmonic frequency + difference frequency,cascade sum frequency + difference frequency effect is proposed respectively.The proposed algorithm is simulated,and the simulation results verify its effectiveness.Then,the temperature characteristics of the wavelength converter based on aperiodic PPLN crystal are studied,by considering the conditions of temperature,conversion efficiency,flatness and conversion bandwidth.Under the condition of temperature influence and combined with the improved optimization algorithm,the crystal structure is optimized,and a wavelength conversion scheme with large bandwidth,high flatness and good conversion efficiency is proposed.And the conversion characteristics at different temperature is analyzed.Finally,considering the error factors that may occur in the actual wavelength conversion,such as temperature,waveguide length,crystal polarization period,we set the temperature at 100 degrees as an example to simulate the stability of the wavelength converter performance.The results show that the wavelength converter designed in consideration of temperature influence can maintain the conversion performance of large bandwidth and high flatness within a certain error range.