聚合物光子晶体波导中慢光传输的电光动态调制

Tunable Slow Light by Electro-Eptic Effect in Polymer Photonic Crystal Waveguide

全光缓存器是未来全光网络中不可或缺的关键器件。针对可控光延迟和光存储的应用需求,研究了光子晶体波导中慢光传输的外部动态调制。设计了一种新型的聚合物光子晶体波导结构。用平面波展开法仿真得到该波导结构带隙中存在单一的TE导模,导模带边处的群速度可达10^(-2)c。由于基底聚合物材料具有高电光系数和瞬态的电光响应时间,且导模慢光传输产生的电磁场局域对电光效应有增强作用,可在低调制电压的条件下实现对慢光导模的大范围动态调制。数值分析得到在外加调制电压为80 V时导模带边波长的移动幅度达80.8 nm。慢光导模的移动随调制电压的变化基本呈线性关系,且调制的灵敏度约为1 nm/V。这种线性的外部动态调制基本可满足全光网络对慢光光缓存的需求。

All-optical buffers have been considered as essential components for all-optical communications. Considering the requirements of controllable optical delay lines and optical buffers, the external dynamic tuning of slow light in photonic crystal waveguides has been studied. A novel photonic crystal waveguide on polymer substrate is proposed. Numerical study using plane, wave expansion method shows that this structure supports a single guided mode transmission,which allows a low group velocity of 10-2c in the vicinity of band edge. Since the substrate material possesses a high electro-optic coefficient and a subpicosecond nonlinear response time, and local field effect induced the by slow light transmission can enhance electro-optic effect greatly, these properties offer the opporunity to tune the slow light mode in wide frequency range with low power. Numerical analysis shows that by applying an external voltage of 80 V, the guided mode will shift 80.8 nm, and moreover the wavelength shift is nearly linearly increased with the increas of applied modulated voltage. Modulation sensitivity is about 1 nm/V. The flexible dynamical tuning of slow light mode can meet the requirements for the use of optical buffer in all-optical network in principle.