Fig. 1. Schematic diagram of apodization step chirped MgO∶PPLN

Fig. 2. Schematic diagram of experimental device based on single-pass broadband sum-frequency generation

Fig. 3. Effect of apodization function on bandwidth and band-top ripple of sum-frequency conversion. (a) Duty ratio of linear apodization function; (b) duty ratio of the positive hyperbolic tangent apodization function; (c) sum-frequency conversion efficiency graph of linear apodization function; (d) sum-frequency conversion efficiency diagram of positive hyperbolic tangent apodization function

Fig. 4. Relationship between r, dp and bandwidth, top ripple, conversion efficiency. (a) Relationship between r and bandwidth, top ripple; (b) relationship between dp and bandwidth, conversion efficiency

Fig. 5. Flow chart of genetic algorithm

Fig. 6. Optimization results of genetic algorithm. (a) Iteration process; (b) sum-frequency conversion efficiency