Zhang Weiwei, Serna Samuel, Dubreuil Nicolas, Cassan Eric
Opt Lett. 2015 Apr 1;40(7):1212-5. doi: 10.1364/OL.40.001212.
The χ(3) nonlinear properties of slotted crystalline silicon photonic waveguides filled with third-order nonlinear materials (NM) are studied by calculating the effective nonlinear susceptibilities associated to the silicon and cladding material, respectively. The adopted approach circumvents the assumptions that the introduced NM dominates the nonlinear behavior of the slotted waveguide and that strong light confinement in the slot allows neglecting the two-photon absorption (TPA) process in the silicon rails. Optimization of the geometry of silicon-slotted waveguides is performed on the basis of the nonlinear figure of merit (FOM(TPA)) of the guided mode, which is related to the balance between the Kerr and the TPA effects, allowing to reach a FOM(TPA)=4.25. The obtained results reveal the importance of properly choosing the waveguide width of the silicon rails in order to minimize the TPA effect even by tolerating a reduced overall nonlinearity.
通过分别计算与硅和包层材料相关的有效非线性极化率，研究了填充三阶非线性材料（NM）的开槽晶体硅光子波导的χ(3)非线性特性。所采用的方法避免了以下假设：引入的NM主导开槽波导的非线性行为，以及槽中的强光限制允许忽略硅轨中的双光子吸收（TPA）过程。基于导模的非线性品质因数（FOM(TPA)）对硅开槽波导的几何结构进行了优化，该品质因数与克尔效应和TPA效应之间的平衡有关，从而使FOM(TPA)达到4.25。所得结果揭示了适当选择硅轨波导宽度的重要性，以便即使容忍整体非线性降低，也能使TPA效应最小化。
