Towards Spectral Matching of Photons from Dissimliar Sources for Quantum Interference

For the realization of a hybrid quantum network, an efficient spectral mode matching between dissimilar photon sources is quintessential. With nonlinear frequency conversion it has already been shown it is possible to match central frequencies [1], but not spectral bandwidth. Previous experiments relied on passive filtering for bandwidth matching [2], [3] and were suffering from too high loss rates to allow for an efficient information transfer and processing between different quantum light sources. Promising results in spectral bandwidth conversion of quantum light have been shown by a phase-only reshaping approach using electro-optic time lensing [4], [5]. In close analogy to a thin lens in space, first a quadratic spectral phase <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\phi$</tex> is applied, followed by, an again quadratic, temporal phase <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\varphi$</tex>. By choosing the right collimation condition, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\phi=\varphi^{-1}$</tex>, compression (or expansion) is achieved in spectral width [6]. By this active reshaping of the spectral-temporal wave packet, for a quantum light source in telecom wavelength a compression factor of about 50 has already been shown [5].