Characteristics of Correlated Photon Pairs Generated in Ultra-compact Silicon Slow-light Photonic Crystal Waveguides
Chunle Xiong, Christelle Monat, Matthew J. Collins, Alex S. Clark, Christian Grillet, Graham D. Marshall, M. J. Steel, Juntao Li, Liam O'Faolain, Thomas F. Krau… 展开作者
Chunle Xiong, Christelle Monat, Matthew J. Collins, Alex S. Clark, Christian Grillet, Graham D. Marshall, M. J. Steel, Juntao Li, Liam O'Faolain, Thomas F. Krauss, Benjamin J. Eggleton
We report the characterization of correlated photon pairs generated in dispersion-engineered silicon slow-light photonic crystal waveguides pumped by picosecond pulses. We found that taking advantage of the 15 nm flat-band slow-light window (vg ~ c/30) the bandwidth for correlated photon-pair generation in 96 and 196 \mum long waveguides was at least 11.2 nm; while a 396 \mum long waveguide reduced the bandwidth to 8 nm (only half of the slow-light bandwidth due to the increased impact of phase matching in a longer waveguide). The key metrics for a photon-pair source: coincidence to accidental ratio (CAR) and pair brightness were measured to be a maximum 33 at a pair generation rate of 0.004 pair per pulse in a 196 \mum long waveguide. Within the measurement errors the maximum CAR achieved in 96, 196 and 396 \mum long waveguides is constant. The noise analysis shows that detector dark counts, leaked pump light, linear and nonlinear losses, multiple pair generation and detector jitter are the limiting factors to the CAR performance of the sources.
Evaluation of graphene optical nonlinearity with photon-pair generation in graphene-on-silicon waveguides
我们通过对自发四波混频产生的光子对的符合测量来评估硅基石墨烯波导的非线性系数。我们观察到的时间相关的光子对从波导在各种转移布局的石墨烯片。使用耦合波方程对实验结果进行简单分析表明，原子级薄的石墨烯片将硅波导的非线性增强了10倍。结果表明，纯$χ^{(3)}$基石墨烯的有效非线性折射率为$10^{-13}$ m $^2$ /W量级，为石墨烯基非线性光学在片上纳米光子学中的应用提供了重要的启示.
