GHz quantum key distribution at telecom wavelengths

Joshua C. Bienfang

Rob Thew, Sébastien Tanzilli, L. Krainer +6 more

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 ∼40 ps, 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 1.27 GHz 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 −1 over 25 km.

Hong Mei Guo, Zhengyu Li, Song Yu +1 more

Michele Traetta, Marco Bentivegna, Florian Kaiser +12 more

We report the fully telecom compliant generation of photon pairs on a silicon micro-ring resonator chip. The ring cavity is designed such as to demultiplex the emitted frequency-comb like spectrum using standard off-the-shelves telecom 100 GHz dense wavelength division multiplexers (DWDM). We measure energy-time entanglement in different channel pairs with raw visibilities exceeding 97%, which paves the way for silicon photonics based quantum key distribution (QKD) with either increased bit rates, or more users.

Jérôme Lodewyck, Thierry Debuisschert, Rosa Tualle-Brouri +1 more

A complete set-up implementing quantum key distribution (QKD) with coherent states at 1550 nm, entirely made of fibre optics and standard telecom components such as integrated-optics modulators, couplers and fast InGaAs photodiodes is built. The whole set-up is fully interfaced and includes a synchronous automatic data processing software. It is designed to operate with continuous variable error correction and privacy amplification algorithms. The present acquisition electronics limits the repetition rate to 1 MHz, but optical components can go as fast as 10 GHz. Therefore, one can envision an extension of this device yielding up to 100 MHz rates.

Kongni Zhu, Nanrun Zhou, Yun-Qian Wang +1 more