Dual-channel, single-photon upconversion detector near 1300 nm

Upconversion of 1.3-micron photons and detection using silicon avalanche photodiodes (Si APDs) can produce high photon detection efficiencies (PDEs) with low dark count rates. We demonstrate a novel two-channel device based on a phase-modulated, periodically poled LiNbO3 waveguide that mixes 1302-nm signal photons with two pump beams at 1556 and 1571 nm. Both channels showed high PDEs with very low dark counts. Using wavelength-to time-division multiplexing in this dual-channel device, we produced clock rates that exceed the timing-jitter-limited rates of a system based on one Si APD. Higher clock rates are of interest for improved quantum communication systems.