Ciminelli C, Campanella C E, Dell'Olio F, Armenise M N
Optoelectronics Laboratory, Politecnico di Bari, Via Orabona 4, 70125 Bari, Italy.
Opt Express. 2010 Feb 1;18(3):2973-86. doi: 10.1364/OE.18.002973.
Speed manipulation of optical pulses is a very attractive research challenge enabling next-generation high-capacity all-optical communication networks. Pulses can be effectively slowed by using different integrated optical structures such as coupled-resonator waveguiding structures or photonic crystal cavities. Fast light generation by means of integrated photonic devices is currently a quite unexplored research field in spite of its crucial importance for all-optical pulse processing. In this paper, we report on the first theoretical demonstration of fast light generation in an ultra-compact double vertical stacked ring resonator coupled to a bus waveguide. Periodic coupling between the two rings leads to splitting and recombining of symmetric and anti-symmetric resonant modes. Re-established degenerate modes can form when a symmetric and an anti-symmetric mode having different resonance order exhibit the same resonance wavelength. Under degenerate mode conditions, wide wavelength ranges where the group velocity is negative or larger than the speed of light in vacuum are generated. The paper proves how this physical effect can be exploited to design fast light resonant devices. Moreover, conditions are also derived to obtain slow light operation regime.
光脉冲的速度操控是一项极具吸引力的研究挑战，它能够推动下一代高容量全光通信网络的发展。通过使用不同的集成光学结构，如耦合谐振器波导结构或光子晶体腔，可以有效地减慢光脉冲。尽管借助集成光子器件产生快光对于全光脉冲处理至关重要，但目前它仍是一个尚未充分探索的研究领域。在本文中，我们报道了在与总线波导耦合的超紧凑双垂直堆叠环形谐振器中产生快光的首个理论证明。两个环之间的周期性耦合导致对称和反对称谐振模式的分裂与重组。当具有不同谐振阶数的对称模式和反对称模式呈现相同的谐振波长时，会重新建立简并模式。在简并模式条件下，会产生群速度为负或大于真空中光速的宽波长范围。本文证明了如何利用这种物理效应来设计快光谐振器件。此外，还推导了实现慢光工作模式的条件。
