  In this letter, we report a polarization-entangled photon-pair source based
on type-II spontaneous parametric down conversion at telecom O-band in
periodically poled silica fiber (PPSF). The photon-pair source exhibits more
than 130 nm (~24 THz) emission bandwidth centered at 1306.6 nm. The broad
emission spectrum results in a short biphoton correlation time and we
experimentally demonstrate a Hong-Ou-Mandel interference dip with a full width
of 26.6 fs at half maximum. Owing to the low birefringence of the PPSF, the
biphotons generated from type-II SPDC are polarization-entangled over the
entire emission bandwidth, with a measured fidelity to a maximally entangled
state greater than 95.4%. The biphoton source provides the broadest bandwidth
entangled biphotons at O-band to our knowledge.
