Southwest Quantum Information and Technology

High-efficiency demultiplexing of quantum information in temporal modes

Presenting Author: Michael G. Raymer , University of Oregon
Contributing Author(s): Dileep V. Reddy

Information can be encoded in single photons using temporal modes (sets of field-orthogonal wave-packet shapes). Temporal modes span a high-dimensional quantum state space and integrate into existing single-mode fiber communication networks, thus creating a new framework for quantum information science. A major challenge to achieving full control of temporal-mode states is their multiplexing and demultiplexing with zero crosstalk. Such add/drop functionality can be achieved by frequency conversion (FC) via nonlinear wave mixing, which can exchange the quantum states between two narrow spectral bands in a temporal-mode-selective manner. By tailoring the shape of the pump laser pulse and the phase-matching conditions of a second-order nonlinear optical medium, one can achieve moderate selectivity for different temporally orthogonal wave packets. To exceed this limit, we demonstrate a two-stage “Ramsey” interferometric FC scheme [1], predicted by theory to reach near-perfect (100%) selectivity. Using the two-stage scheme, we demonstrate a large increase over the single-stage selectivity limit, for the first three natural (“Schmidt”) modes of the FC process. This result paves the way for implementing arbitrary single-photon unitary operations, and thus various protocols such as QKD, in the temporal-mode basis. 1. “High-selectivity quantum pulse gating of photonic temporal modes using all-optical Ramsey interferometry,” D. V. Reddy and M. G. Raymer, Optica, 5, 423 (2018)

Read this article online: https://arxiv.org/abs/1710.06736

(Session 4 : Sunday from 3:15pm - 3:45pm)