Single photon sources (SPSs) play important roles in quantum communication and quantum information processing.
Spontaneous four wave mixing (SFWM) in optical fibers provides a promising way to realize practical heralded single
photon sources (HSPSs), since it is compatible with current techniques of optical communications. In this paper, two
independent HSPSs at 1.5μm band are realized in one polarization maintaining dispersion shifted fiber (PM-DSF)
utilizing its large birefringence. When pulsed pump light passes through an optical fiber, two kinds of SFWM will take
place simultaneously. One is scalar processes, in which two annihilated pump photons and generated photon pair are all
polarized along the same fiber polarization axis. The other is vector processes, in which two annihilated pump photons
are polarized along different fiber polarization axes, either for the two photons of the generated pair. In the PM-DSF, the
large birefringence generates obvious walk-off effect on the two pump polarization components, which leads to an
effective suppression of the vector processes. Hence, by proper pump polarization, correlated photon pairs (CPPs) with
different polarization directions can be generated independently by the two scalar processes, which can be used to realize
two independent HSPSs. The indistinguishability of the heralded photons generated by the two independent sources is
demonstrated by an experiment of Hong-Ou-Mandel (HOM) interference. Using a fiber coupler as the beam splitter, a
visibility of HOM dip of 76% is achieved, showing their potential on quantum information.