# Energy-Time Entanglement-based Dispersive Optics Quantum Key Distribution over Optical Fibers of 20 km

## TL;DR

This paper demonstrates a high-rate, secure quantum key distribution over 20 km of optical fiber using energy-time entangled photons and dispersive optics, optimizing encoding and error reduction techniques.

## Contribution

It introduces an efficient implementation of dispersive optics QKD with high-dimensional encoding and optimized bin sifting, achieving significant improvements in key rate and error rate.

## Key findings

- Raw key rate of 151 kbps achieved
- QBER of 4.95% demonstrated
- Effective high-dimensional encoding used

## Abstract

An energy-time entanglement-based dispersive optics quantum key distribution (DO-QKD) is demonstrated experimentally over optical fibers of 20 km. In the experiment, the telecom band energy-time entangled photon pairs are generated through spontaneous four wave mixing in a silicon waveguide. The arrival time of photons are registered for key generating and security test. High dimensional encoding in the arrival time of photons is used to increase the information per coincidence of photon pairs. The bin sifting process is optimized by a three level structure, which significantly reduces the raw quantum bit error rate (QBER) due to timing jitters of detectors and electronics. A raw key generation rate of 151kbps with QBER of 4.95% is achieved, under a time-bin encoding format with 4 bits per coincidence. This experiment shows that entanglement-based DO-QKD can be implemented in an efficient and convenient way, which has great potential in quantum secure communication networks in the future.