Single-photon non-reciprocity with an integrated magneto-optical isolator

Abstract

Non-reciprocal photonic devices are essential components of classical optical information processing. It is interesting and important to investigate their feasibility in the quantum world. In this work, a single-photon non-reciprocal dynamical transmission experiment was performed with an on-chip silicon nitride (SiN)-based magneto-optical (MO) isolator. The measured isolation ratio for single photons achieved was 12.33 dB, consistent with the result of classical test, which proved the functionality of our on-chip isolator. The quantum coherence of the passing single photons was further verified using high-visibility quantum interference. Our work will promote on-chip nonreciprocal photonic devices within the integrated quantum circuits and help introduce novel phenomena in quantum information processes.

Dark‐State Induced Quantum Nonreciprocity

“…[31] These devices violate Lorentz reciprocity because the permittivity tensors of the underlying materials become asymmetric. [32][33][34] However, these devices are expensive, barely tunable, bulky, and their implementation in integrated circuits, recently demonstrated experimentally, [35][36][37] is hindered by the need for large magnetic fields and the lattice incompatibility between semiconductors and magneto-optical materials. Moreover, in superconducting quantum circuits the use of large magnetic fields is often undesired because it highly affects the qubit properties.…”