Experimental long wavelength quantum cryptography: From single-photon transmission to key extraction protocols

We present experiments on long wavelength (δ = 1.55 μm) 'plug and play' quantum cryptography systems. We discuss the performance of single-photon detectors at δ = 1.55 μm. Furthermore, we address the full implementation of the quantum cryptography protocol, discussing in detail the implementation of protocols for error correction and privacy amplification needed to get a secure key. We illustrate the theory with examples from a full software simulation to show the performance of the complete protocol in terms of final secure key creation rate.