The entangled photon source is a type-0 Sagnac source. The source is pumped by a continuous-wave laser operating at 780 nm, with an average power of 40 mW. The pump beam is first passed through a polarization stage, where its polarization is adjusted to the diagonal state √(1/2) (|H⟩ + |V ⟩). The pump beam is then reflected by a dichroic mirror and directed into the Sagnac loop, which consists of a 25 mm-long periodically poled Lithium Niobate (ppLN) crystal for Spontaneous Parametric Down Conversion (SPDC) and a half-wave plate. A polarizing beam splitter (PBS) separates the pump beam into clockwise and counterclockwise directions. Both paths are focused into the SPDC crystal and recombine at the PBS. Due to the low efficiency of SPDC (about 10^(-9) here), photon pairs are generated either in the clockwise or counterclockwise direction at any given time. By overlapping these paths and eliminating the which-path information, a maximally entangled Bell state is created. The source has a brightness of 0.72 MHz/mW*nm and a measured fidelity of the generated entangled photons >99%.