Erasing quantum-mechanical distinguishability is of fundamental interest and also of practical importance, particularly in subject areas related to quantum information processing. We demonstrate a method applicable to optical systems in which single-mode filtering is used with only linear optical instruments to achieve quantum indistinguishability. Through "heralded" Hong-Ou-Mandel interference experiments we measure and quantify the improvement of indistinguishability between single photons generated via spontaneous four-wave mixing in optical fibers. The experimental results are in excellent agreement with predictions of a quantum-multimode theory we develop for such systems, without the need for any fitting parameter.
@article{arxiv.1205.4346,
title = {Erasing Quantum Distinguishability via Single-Mode Filtering},
author = {Monika Patel and Joseph B. Altepeter and Yu-Ping Huang and Neal N. Oza and Prem Kumar},
journal= {arXiv preprint arXiv:1205.4346},
year = {2015}
}