Generation of mutually unbiased bases for 4D-QKD with structured photons via LNOI photonic wire

Abstract

A combination of orbital angular momentum (OAM) and spin angular momentum (SAM) degrees of freedom for a single photon leads to enhanced transmission rates and security in high-dimensional quantum key distribution (QKD) systems. Therefore, the actual commercial QKD sources require accurate and fast generation of encoded states. This paper proposes a schemed and numerically verified integrated high-speed and low-loss electro-optical modulator for the manipulation of modes encoded in OAM-SAM states. The modulator is designed as an electro-optically active lithium niobate on insulator photonic wire configuration. The obtained results indicate the high purity (>92%) and low quantum bit error rate (∼8%) generation of encoded states for 4D-QKD with structured photons via low applied voltage values not more than 9 volts.

Characterizing High-Quality High-Dimensional Quantum Key Distribution by State Mapping Between Different Degrees of Freedom

“…The free-space EOM could hardly achieve higher modulation rate as the high half-wave voltage required. Though there is still a long way to make them practical, the integrated optical waveguides [52] and modulators [53,54] may be a potential solution to high-speed modulation of OAM photons.…”

On-chip enhanced electro-optic Kerr effect for manipulation of optical orbital angular momentum modes

“…More specifically, some integrated optical modulators have been theoretically and experimentally investigated to emit, (de)multiplex, switch, receive, detect, and sort OAM carrying modes [32][33][34][35][36][37][38][39]. Furthermore, an integrated optical modulator has been proposed to alter the polarization, relative phase and wavelength of |l| = ±1 OAM carrying modes via manipulation of their decomposed guided modes by linear EO effect and nonlinear phenomena [40][41][42]. Nevertheless, although higher order OAM carrying modes (i.e.…”