In 100 words or less, please tell us why your paper belongs in PRApplied

Thermal light shows temporal correlations through photon bunching that can be
explored for a number of applications. Clock synchronization through an optical
channel is one of them presented here, in a setting what may be used
for quantum key distribution. We present an experimental demonstration and a
theoretical accuracy estimation of the time and frequency difference
difference of two separate crystal clocks in a high channel-loss scenario,
exploring the relatively weak temporal correlations in photon-bunched
light. This work may trigger synchronization applications in different fields.


letter to editor

Dear Editor,

in our manuscript, we present an application to use photon-bunched light, like
thermal or pseudo-thermal light with its relatively weak temporal correlations
to synchronize two remote clocks.

The presented method uses a simple method to prepare photon-bunched light from
laser light through self-interference of mutually incoherent parts of the
laser light, and numerical algorithms to extract the exact temporal position
of the photon bunching observed by two remote receivers looking to different
clocks with an uncertainty of the exact time and frequency difference between
these clocks. This information can be used to synchronize these clocks, perhaps
present in a quantum communication scenario where an optical link is present
already. The loss of the optical connection can be quite substantial (we show
>2x100dB), and survives with relatively weak correlation signatures as well.

We therefore believe this manuscript may be interesting to the audience of
Physical Review Applied as it showcases an actual application of thermal or
photon-bunched light.


Looking forward for your reply!

With Best Regards on behalf of all authors,

Christian Kurtsiefer