On Preparing Entangled Pairs of Polarization Qubits in the Frequency Non-Degenerate Regime

TL;DR

This paper discusses the challenges in preparing polarization entangled photon pairs in the frequency non-degenerate regime, highlighting dispersion effects and proposing an experimental compensation method.

Contribution

It introduces a novel dispersion compensation technique for polarization entangled photon pairs in the frequency non-degenerate regime and demonstrates its experimental implementation.

Findings

Dispersion effects significantly impact entangled state quality.

Group velocity dispersion compensation improves state fidelity.

Experimental validation confirms the effectiveness of the proposed method.

Abstract

The problems associated with practical implementation of the scheme proposed for preparation of arbitrary states of polarization ququarts based on biphotons are discussed. The influence of frequency dispersion effects are considered, and the necessity of group velocities dispersion compensation in the frequency non-degenerate case even for continuous pumping is demonstrated. A method for this compensation is proposed and implemented experimentally. Physical restrictions on the quality of prepared two-photon states are revealed.