Frequency Multiplexing Heralded Single Photon Source at 1.5 μm

We propose a heralded single photon source with three frequency modes multiplexed and operating in all telecom band by using cascaded χ(2) processes in a periodically poled lithium niobite (PPLN) waveguide. Our proof-of-principle result shows that each frequency mode reaches a coincidence count rate of ∼10 kHz with a coincident-to-accidental ratio of 3×102.