  We demonstrate a novel scheme to generate frequency-entangled qudits with
dimension number higher than 10 and to distribute them over optical fibers of
15 km in total length. This scheme combines the technique of spectral
engineering of biphotons generated by spontaneous parametric down-conversion
and the technique of spectrally resolved Hong-Ou-Mandel interference. We
characterized the comb-like spectral correlation structures of the qudits by
time of arrival measurement and correlated spectral intensity measurement. The
generation and distribution of the distinct entangled frequency modes may be
useful for quantum cryptography, quantum metrology, quantum remote
synchronization, as well as fundamental test of stronger violation of local
realism.
