Periodically poled lithium niobate waveguide sum-frequency generator for efficient single-photon detection at communication wavelengths.

We present a device to facilitate single-photon detection at communication wavelengths based on continuous-wave sum-frequency generation with an upconversion efficiency exceeding 90%. Sum-frequency generation in a periodically poled lithium niobate waveguide is used to upconvert signal photons to the near infrared, where detection can be performed efficiently by use of silicon avalanche photodiodes.