A Sagnac-based arbitrary time-bin state encoder for quantum communication applications

TL;DR

This paper introduces a stable, scalable, and fully controllable time-bin quantum state encoder that enhances quantum communication by allowing arbitrary high-dimensional state generation with minimal error and resource requirements.

Contribution

It presents a novel, fully controllable time-bin encoder that is scalable, stable, and capable of generating arbitrary quantum states efficiently.

Findings

High stability and low QBER at high speeds

Scalable to arbitrary dimensions and time-bin widths

Supports phase randomization and encoding without extra resources

Abstract

Time-bin encoding of quantum information is highly advantageous for long-distance quantum communication protocols over optical fibres due to its inherent robustness in the channel and the possibility of generating high-dimensional quantum states. The most common implementation of time-bin quantum states using unbalanced interferometers presents challenges in terms of stability and flexibility of operation. In particular, a limited number of states can be generated without modifying the optical scheme. Here we present the implementation of a fully controllable arbitrary time-bin quantum state encoder, which is easily scalable to arbitrary dimensions and time-bin widths. The encoder presents high stability and low quantum bit error rate QBER, even at high speeds of operation. Additionally, we demonstrate phase randomization and phase encoding without additional resources.