Dear Dr. Narducci,

thank you very much for your comments on our manuscript  LD15739AR
"Hong-Ou-Mandel interference between triggered and heralded single
photons from separate atomic systems."

In view of the time line of publications, we would like to come back to your
offer to publish the manuscript as a regular article.

We modified the manuscript according to the style directions in Physical
Review A, mainly adding section headings to structure the manuscript
better. To address the issue with the optical bandwidth, we modified the
description of the four wave setup accordingly. What used to read

"We select time-correlated photon pairs with wavelengths 776 nm (signal) and
780 nm (idler) using narrowband interference filters and collect them into
single mode fibers."

now got replaced by:

"We separate time-correlated photon pairs with wavelengths 776 nm (signal) and
780 nm (idler) from the residual pump light using narrowband interference
filters (bandwidth 3 nm FWHM, transmission >90%). A pair of
additional interference filters (same bandwidth and transmission) are used to
suppress the residual pump light in each arm. The bandwidth of these
filters is much larger than the bandwidth of the parametrically generated
photons, so they do not affect the spectral envelope of the photons, which we
subsequently collect into single mode fibers."

We hope that this helps to better understand the efficiency of the photon
generation, and makes it clear that the interference filters are merely there
to separate signal and idler, and to suppress the widely separated but strong
pump beams.

We also modified the experimental figure 2 accordingly, as we did not indicate
all wideband interference filters in the FWM setup.

Also, we did find a minor issue in the evaluation of the error bars in figure
5, which we updated accordingly as well. The numerical values we quote were
not affected by this update.

With this, we hope to have provided some clarification on the bandwidth of the
participating photons in the text, and would appreciate if you could consider
publication of the manuscript in Physical Review A.

With Best Regards on behalf of all authors,

Christian Kurtsiefer