Non-reciprocal transmission and Schmitt trigger operation in strongly modulated asymmetric WBGs
Non-reciprocal transmission and Schmitt trigger operation in strongly modulated asymmetric WBGs
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DOI：
10.1364/oe.14.012782
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发表时间：
2006-12-25
期刊：
影响因子：
3.8
通讯作者：
Freude, Wolfgang
中科院分区：
文献类型：
--
作者：
Fujii, Masafumi;Maitra, Ayan;Freude, Wolfgang
我们以数值方式研究了具有纵向不对称阻带配置的强调制波导布拉格光栅（WBG）中的非互易开关行为。对于由预期材料制成的实际波导结构，预测稳定开关操作的最小功率约为 77 mW；我们在本文中假设纳米带 InGaAsP/InP 波导具有波导宽度的纵向不对称调制。该分析是使用我们适合并行计算的内部非线性时域有限差分 (FDTD) 代码进行的。数值结果清楚地显示了低阈值施密特触发器操作，以及不可逆传输特性，其中一个传播方向的切换阈值低于另一方向的切换阈值。此外，我们通过采用瞬时克尔非线性和更复杂的可饱和非线性模型来讨论此类非线性周期性器件中的类调制不稳定现象。 (C) 2006 年美国光学学会。
We investigate numerically a non-reciprocal switching behavior in strongly modulated waveguide Bragg gratings (WBGs) having a longitudinally asymmetric stopband configuration. The minimum power predicted for a stable switching operation is found to be approximately 77 mW for a realistic waveguide structure made of prospective materials; we assume in this paper a nano-strip InGaAsP/InP waveguide having longitudinally asymmetric modulation of the waveguide width. The analysis has been performed with our in-house nonlinear finite-difference time-domain (FDTD) code adapted to parallel computing. The numerical results clearly show low-threshold Schmitt trigger operation, as well as non-reciprocal transmission property where the switching threshold for one propagation direction is lower than that for the other direction. In addition, we discuss the modulation-like instability phenomena in such nonlinear periodic devices by employing both an instantaneous Kerr nonlinearity and a more involved saturable nonlinearity model. (C) 2006 Optical Society of America.