Attacking a high-dimensional quantum key distribution system with wavelength-dependent beam splitter

Du Ge-Hai^{1, 2}, Li Hong-Wei^{1, 2, †}, Wang Yang^{1, 2}, Bao Wan-Su^{1, 2, ‡}

The relationship between the requirement for coupling ratio and QBER. Full lines represent relationships between coupling ratio and QBER while dotted lines denote secret key rates in infinite-key scenario. Colors red, yellow, blue, and purple correspond to dimensions d = 2, 4, 8, and 16, respectively.