Our paper was published in Advanced Physics Research.
We report on optimizing the spectral purity of heralded single photons in the telecom O-band, where single photons can be propagated with low loss and low dispersion in a standard telecom optical fiber. We numerically searched for various group-velocity-matching conditions and corresponding optimal poling structures of a potassium titanyl phosphate crystal for spontaneous parametric downconversion. Our poling optimization results using phase-matching coherence-length and sub-coherence-length modulation schemes show 99.4% spectral purity with pump wavelengths ranging from 603.8 to 887.3 nm. Some optimized configurations are feasible with off-the-shelf lasers and single-photon detectors. Moreover, by investigating noise photon spectra for different poling optimization methods, we show that, in practice, appropriate, gentle spectral filtering helps achieve high purity. This study will pave the way for developing practical quantum sources for quantum information applications at the telecom O-band.
Paper Link: https://doi.org/10.1002/apxr.202500167
- Title: Our paper was published in Advanced Physics Research.
- Author: Wuhao Cai
- Created at : 2025-11-25 04:43:09
- Updated at : 2026-01-29 15:30:52
- Link: https://caiwuhao.github.io/2025/11/25/paper/
- License: This work is licensed under CC BY-NC-SA 4.0.