The Impact of Photon Entanglement on Local and Nonlocal Dispersion Cancellation

TL;DR

This paper theoretically demonstrates how photon entanglement influences local and nonlocal dispersion cancellation, showing that higher entanglement improves broadening compensation in certain conditions, with implications for quantum communication.

Contribution

It provides a theoretical analysis of how entanglement degree affects dispersion cancellation in both local and nonlocal detection scenarios, highlighting the conditions for effective broadening mitigation.

Findings

Higher entanglement enhances local dispersion cancellation.

Dispersive broadening depends on pump FWHM and entanglement degree.

Nonlocal cancellation requires identical dispersive paths with opposite group velocities.

Abstract

Recently the engineering of the entanglement for photon pairs generated during the spontaneous parametric down conversion process (SPDC) can be achieved via manipulation of pump wavelength behind a \c{hi}(2)-based type II SPDC process [1]. Such effect is used in this paper for demonstration of non-classical dispersion cancellation phenomenon in both local and nonlocal detections, theoretically. The following results are analytically achieved: I) For local detection, if narrow pump laser (highly entangled photons) are used, the dispersive broadening cancelation is directly depends on the degree of entanglement. The higher entanglement degree, the more compensation occurs. The results indicate that by increasing the FWHM of the pump the impact of the entanglement degree is decreased in such a way that for a pump with FWHM=4 nm the entanglement has no effect on the broadening. Therefore, the dispersive broadening is only depends on the temporal walk-off between generated photon pairs and the pump. II) For nonlocal detection, it is also shown that entanglement cancels the dispersive broadening if and only if each of the generated paired photons propagate through dispersive material with identical length with opposite group velocity sign.