Automated Active-Visibility-Control Loop for Stabilized DPS-QKD Decoding under Dynamic Wavelength Drift

Abstract: Automated and instantaneous stabilizing control of the quantum key decoder is the mandatory procedure, which guarantees real-time and high-speed differential-phase-shift (DPS) quantum key distribution (QKD) at low erroneous rate, and ensures the delay-line interferometric (DLI) decoding of the weak-coherent-pulse quantum bit-stream at a qualified and constant visibility. As the QKD system often suffers from […]

A Novel n⁺/i-well Dot Ge₁₋ₓSnₓ-on-Si Single-Photon Avalanche Photodiode for High-Fill-Factor Room-Temperature Quantum Applications

Abstract: We propose a novel design of Ge1-xSnx-on-Si single-photon avalanche photodiodes (SPADs) that aim to enhance the fill factor (FF) and minimize noise at room temperature. The device consists of a n+/i-well dot structure designed to eliminate the need for guard rings and multi-dot or array configurations typically used to enhance the active area. This […]