ERI: Study of quantum entanglement and spatially different photon pair generation through intermodal four-wave mixing in few-mode and multimode fibers

Missouri University Of Science And Technology, Rolla MO

Investigators

Abstract

Substantial efforts are underway to expand the capacity of telecommunication systems utilizing spatial division multiplexing (SDM) as the demand for secure quantum communication systems combined with optical communication systems continues to grow. Propagating quantum states of light through current optical communication networks or future SDM systems can fulfill this demand and meet the essential consumer requirements for secure communication. The overarching aim of this research is to advance this objective through the Production and transmission of entangled photons over optical fibers. In the past, entangled photon pairs were created using bulk periodically poled crystals and waveguides utilizing their second-order nonlinearity. However, this method results in additional loss from fiber coupling and suffers from low photon yield at telecommunication bandwidths. The generation and transmission of entangled photons through optical fibers are desirable for a variety of applications. Nevertheless, the current approaches pose several challenges, including complexity, limited data generation, reliance on bulky and high-powered pulsed lasers, and the introduction of quantum noise. This study proposes the utilization of various modes of few-mode and multimode fibers to produce a pair of entangled photons, which will provide improved control over entanglement properties and better integration with SDM systems. This approach is expected to alleviate the challenges mentioned earlier. As part of the research and education integration, a graduate student working on this project will receive training in nonlinear fiber optics and quantum laser sources. Furthermore, undergraduate students will have the opportunity to participate in various stages of the project through research credits and summer internships in order to spark their interest in fiber-optic research at Missouri S&T, which is a minority-serving university. The proposed research aims to investigate the impact of intermodal nonlinearities on quantum entanglement in few-mode and multimode fibers. This project is both significant and innovative in that it will employ intermodal nonlinearities to generate and transmit quantum channels across various spatial modes within such fibers. By employing pumps in two different modes of the fiber, spontaneous four-wave mixing nonlinear effect generates an entangled photon pair each of which are in a different spatial mode traveling in different channels. The project seeks to establish theoretical and experimental platforms to investigate the underlying mechanisms of such intermodal entangled mode generation. These platforms will be utilized to examine the basic processes of such intermodal entanglement in fibers. Subsequent quantum correlation experiments will be performed to characterize the generated photon pairs quantum states. By directly generating entangled photon pairs in fiber, the coupling loss will be eliminated and by the choice of fiber and the pump wavelengths, the Raman scattering noise can be avoided. The primary objective is to improve quantum communication over fiber by utilizing intermodal quantum entanglement in few-mode and multimode fibers and could have a transformative impact on quantum communication and sensing utilizing SDM-compatible fibers. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.