We demonastrate experimental technique for generating spatially single-mode broadband biphoton field. The method is based on dispersive optical element which precisely tailors the structure of type-I SPDC frequency angular spectrum in order to shift different spectral components to a single angular mode. Spatial mode filtering is realized by coupling biphotons into a single-mode optical fiber.
@article{arxiv.1504.07760,
title = {Broadband biphotons in a single spatial mode},
author = {K. G. Katamadze and N. A. Borshchevskaya and I. V. Dyakonov and A. V. Paterova and S. P. Kulik},
journal= {arXiv preprint arXiv:1504.07760},
year = {2015}
}