# Up-conversion single-photon detectors based on integrated periodically poled lithium niobate waveguides

## TL;DR

This paper presents an integrated, low-cost up-conversion single-photon detector using periodically poled lithium niobate waveguides, achieving high efficiency for dual wavelengths and enabling portable quantum detection systems.

## Contribution

The work introduces a novel integrated detector design with optimized mode filters and a directional coupler for efficient dual-wavelength photon detection.

## Key findings

- Detection efficiencies of 28% at 1550 nm and 27% at 1950 nm.
- The system is portable, low-cost, and suitable for various spectral bands.
- Efficient detection across the low-loss range of lithium niobate waveguides.

## Abstract

We demonstrate up-conversion single-photon detectors based on integrated periodically poled lithium niobate waveguides, which incorporate two mode filters and a directional coupler. The two mode filters are optimized for the fiber-waveguide coupling efficiencies for 1550 nm and 1950 nm respectively while the directional coupler plays the role of wavelength combiner, making the overall system portable and low-cost. The two wavelengths pump each other in our detection system. We achieve detection efficiencies of 28% for 1550 nm and 27% for 1950 nm, respectively. This scheme provides an efficient integrated single-photon detection method for any two well-separated spectral bands in the whole low-loss range of lithium niobate waveguides.

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Source: https://tomesphere.com/paper/1902.06464