Experimental study of high speed polarization-coding quantum key distribution with sifted-key rates over Mbit/s
Xiao Hong Tang, Lijun Ma, Alan Mink, Anastase Nakassis, Hai Peng Xu, Barry Hershman, Joshua C. Bienfang, David G. Su, Ronald F. Boisvert, Charles W. Clark, Carl J. Williams · Optics Express · 2006
We present a quantitative study of various limitations on quantum cryptographic systems operating with sifted-key rates over Mbit/s. The dead time of silicon APDs not only limits the sifted-key rate but also causes correlation between the neighboring key bits. In addition to the well-known count-rate dependent timing jitter in avalanche photo-diode (APD), the faint laser sources, the vertical cavity surface emission lasers (VCSELs) in our system, also induce a significant amount of data-dependent timing jitter. Both the dead time and the data-dependent timing jitter are major limiting factors in designing QKD systems with sifted-key rates beyond Mbit/s.