Petrov Alexander, Krause Michael, Eich Manfred
Technische Universität Hamburg-Harburg, Hamburg, Germany.
Opt Express. 2009 May 11;17(10):8676-84. doi: 10.1364/oe.17.008676.
It is known that slow light propagation in disordered photonic crystal channel waveguides leads to backscattering and localization phenomena. The knowledge of the reflection of a slow light mode at a single disorder defect of the periodical structure can help to estimate the backscattering intensity and the localization length. Here, this Bloch-mode reflection is calculated in a simplified slow light waveguide using an eigenmode-expansion approach. We show that by properly engineering the waveguide, backscattering can be significantly reduced while maintaining the same low group velocity. A strong effect of the mode's anticrossing taking place in photonic crystal line-defects is demonstrated on backscattering. The localization length of slow light waveguides is estimated, which provides fundamental limits for the applicability of slow light waveguides.
众所周知，无序光子晶体通道波导中的慢光传播会导致背散射和局域化现象。了解慢光模式在周期性结构的单个无序缺陷处的反射情况，有助于估计背散射强度和局域化长度。在此，利用本征模展开方法在简化的慢光波导中计算了这种布洛赫模式反射。我们表明，通过合理设计波导，可以在保持相同低群速度的同时显著降低背散射。证明了光子晶体线缺陷中发生的模式反交叉对背散射有很强的影响。估计了慢光波导的局域化长度，这为慢光波导的适用性提供了基本限制。
