To improve the efficiency of fiber coupling with white LED, According the fiber coupling condition, based on the optical expansion in non-imaging optics theory. Designing two coupled systems of free surface lens and elliptical reflector. Then, the coupled system was simulated and analyzed by LightTools, the results showed that the coupling system of free surface lens has the highest efficiency. Therefore, building the experimental platform of free surface lens coupling system, the results show that the coupling efficiency of fiber coupling system with LED base on Free surface lens as high as 65%. The coupling has the advantages of excellent concentrating efficiency, high coupling efficiency and low cost which can be used for reference to improve the light energy utilization of LED fiber coupling.
A synthetic method of solar spectrum which based on the spectral characteristics of the solar spectrum and LED, and the principle of arbitrary spectral synthesis was studied by using 14 kinds of LED with different central wavelengths.The LED and solar spectrum data were selected by Origin Software firstly, then calculated the total number of LED for each center band by the transformation relation between brightness and illumination and Least Squares Curve Fit in Matlab.Finally, the spectrum curve of AM1.5 standard solar spectrum was obtained. The results met the technical indexes of the solar spectrum matching with ±20% and the solar constant with >0.5.