| PhD Seminar

Name of the Speaker: Ms. Saravana Vilashini (EE19D021)
Guide: Dr. Anil Prabhakar
Venue: ESB-244 (Seminar Hall)
Online meeting link: https://meet.google.com/hxe-ussu-nii
Date/Time: 25th July 2025(Friday), 4PM
Title: Implementation of QKD Protocol with Clock Synchronization

Abstract :

We present the experimental implementation of the BB84 protocol and the Plug-and-Play BB84 protocol based on distributed phase reference Quantum Key Distribution (QKD), designed to enable secure communication over long-distance optical fiber links. Our results include a detailed analysis of QBER variations under different phase modulator biasing conditions, as well as the demonstration of polarization fluctuation compensation inherent to the Plug-and-Play BB84 protocol. A Quantum Bit Error Rate (QBER) of 9% was achieved over a 50 km fiber spool, which falls within the secure threshold for QKD and corresponds to a measured Secure Key Rate (SKR) of approximately 5 kbps. The system incorporates a High-Accuracy Timing Clock Synchronization (HATI) scheme to maintain precise alignment between the sender and receiver, achieving a measured timing jitter of approximately 200 picoseconds.