Spectral correlation and interference in non-degenerate photon pairs at telecom wavelengths
Paulina S. Kuo, Thomas Gerrits, Varun B. Verma, Sae Woo Nam
We characterize an entangled-photon-pair source that produces signal and idler photons at 1533 nm and 1567 nm using fiber-assisted signal-photon spectroscopy. By erasing the polarization distinguishability, we observe interference between the two down-conversion paths. The observed interference signature is closely related to the spectral correlations between photons in a Hong-Ou-Mandel interferometer. These measurements suggest good indistinguishability between the two down-conversion paths, which is required for high entanglement visibility.