Two photon state engineering generated in microstructured fibers

Abstract

In this work, spontaneous four wave mixing (SFWM) in photonic crystal fibers (PCFs) is investigated as a source for spectrally engineered photon pairs for photonic applications. A model based on the joint spectral amplitude (JSA) formalism was developed to analyze the influence of fiber geometry dispersion properties and pumping conditions on the spectral correlations. The phase matching function and pump envelope were, then, simulated for two different PCFs configurations, allowing the corresponding joint spectral intensities (JSIs) to be analyzed. The results show that modifications of the fiber geometry and pump wavelength lead to changes in the shape, orientation and localization of the JSI. To quantify the modal structure of the general states, the JSA was discretized through singular value decomposition. This provides access to the Schmidt Modes, Schmidt coefficients, Schmidt Number, etc. Simulations revealed configurations with Schmidt numbers close to unity and dominant leading Schmidt coefficients. This to verify the potential of SFWM for frequency quantum encoding, with theoretical conditions required for frequency-bin Bell states from two dominant Schmidt modes. Although no fiber configurations satisfied the conditions, the analysis demonstrates the potential and versatility of SFWM as source of structured biphoton states for quantum information processing and maniputation.