Research on the variation characteristics of supercontinuum source beam quality with wavelength

For the collimation and focusing of supercontinuum, the divergence angle is an important parameter. In order to obtain the far-field beam divergence angle corresponding to multiple wavelengths of the supercontinuum in the wide spectrum range of 0.5-2.3μm, two types of cameras are used to collect the far-field spot image. The range covers the supercontinuum that PCF can generate. The relationship between the beam quality/divergence angle and the wavelength is summarized. The experimental values are in good agreement with the theoretical values. To the best of our knowledge, it is the first report to measure the divergence angle of supercontinuum in such a wide range of wavelength. The divergence angle of the supercontinuum after transmission through a section of passive optical fiber with a core diameter of 10μm was also measured. The results show that the divergence angle of supercontinuum variation with wavelength exhibits different characteristics for the 10μm core fiber and the PCF.