  We have developed a hybrid single photon detection scheme for telecom
wavelengths based on nonlinear sum-frequency generation and silicon
single-photon avalanche diodes (SPADs). The SPAD devices employed have been
designed to have very narrow temporal response, i.e. low jitter, which we can
exploit for increasing the allowable bit rate for quantum key distribution. The
wavelength conversion is obtained using periodically poled Lithium niobate
waveguides (W/Gs). The inherently high efficiency of these W/Gs allows us to
use a continuous wave laser to seed the nonlinear conversion so as to have a
continuous detection scheme. We also present a 1.27GHz qubit repetition rate,
one-way phase encoding, quantum key distribution experiment operating at
telecom wavelengths that takes advantage of this detection scheme. The proof of
principle experiment shows a system capable of MHz raw count rates with a QBER
less than 2% and estimated secure key rates greater than 100 kbit/s over 25 km.

Quantum Physics