Liu Bo, Wang Tao, Tang Jian, Li Xiaoming, Dong Chuanbo, He Yu
Appl Opt. 2013 Dec 1;52(34):8394-401. doi: 10.1364/AO.52.008394.
A new procedure of designing slotted photonic crystal waveguides is proposed to achieve slow light with improved normalized delay-bandwidth product and low group velocity dispersion that is suitable for both the W1 defect mode and the slot mode. The lateral symmetry of the waveguide in our study is broken by shifting the air holes periodically along the slot axis. The conversion of the "flat band" from band-up slow light to band-down slow light is achieved for the W1 defect mode. The group index curves of the W1 mode change from U-like to step-like and the group indices of 47, 67 and 130 are obtained with the bandwidth over 7.2, 4.8, and 2.3 nm around 1550 nm, respectively. We also obtain the group indices of 42, 55, and 108 for the slot mode with the bandwidth over 6.2, 5.6, and 2.2 nm, respectively. Then the low dispersion slow light propagation is numerically demonstrated by the finite-difference time-domain method.
提出了一种设计开槽光子晶体波导的新方法，以实现具有改善的归一化延迟带宽积和低群速度色散的慢光，这适用于W1缺陷模式和狭缝模式。在我们的研究中，通过沿狭缝轴周期性地移动气孔，打破了波导的横向对称性。对于W1缺陷模式，实现了从带上慢光到带下慢光的“平带”转换。W1模式的群折射率曲线从U形变为阶梯形，在1550nm附近，带宽分别超过7.2、4.8和2.3nm时，获得了47、67和130的群折射率。对于狭缝模式，我们还分别在带宽超过6.2、5.6和2.2nm时获得了42、55和108的群折射率。然后，通过时域有限差分法对低色散慢光传播进行了数值验证。
