Pisco Marco, Ricciardi Armando, Campopiano Stefania, Caucheteur Christophe, Mégret Patrice, Cutolo Antonello, Cusano Andrea
Optoelectronics Division-Engineering Department, University of Sannio, Corso Garibaldi 107, 82100 Benevento, Italy.
Opt Express. 2009 Dec 21;17(26):23502-10. doi: 10.1364/OE.17.023502.
In this paper, slow and fast light in optical fiber through tilted fiber Bragg grating (TFBG) are reported. The experimental results show the capability of TFBGs to enable group velocity control of an optical pulse in optical fiber, due to the anomalous dispersion features induced by the coupling between the propagating core mode and each counter-propagating coupling cladding mode. In particular, superluminal propagation of a pulse train has been observed at optical communication wavelengths with time advancements in the picoseconds time scale in 1cm long TFBG and group velocity as large as about two times the speed of light in optical fiber (approximately 1.3 x c0). Very good agreement has been obtained comparing the measured group delay of the TFBG with the one retrieved from the amplitude response through Hilbert transform. Finally, tunable slow and fast light has also been reported, demonstrating the possibility to control the group velocity at single wavelength through both fluidic and thermal actuation.
本文报道了通过倾斜光纤布拉格光栅（TFBG）在光纤中实现的慢光和快光。实验结果表明，由于传播的纤芯模式与每个反向传播的耦合包层模式之间的耦合所引起的反常色散特性，TFBG能够实现对光纤中光脉冲群速度的控制。特别是，在1cm长的TFBG中，在光通信波长处观察到了脉冲序列的超光速传播，时间提前量在皮秒时间尺度，群速度高达光纤中光速的两倍左右（约1.3×c0）。通过将TFBG的测量群延迟与通过希尔伯特变换从幅度响应中获取的群延迟进行比较，得到了很好的一致性。最后，还报道了可调谐的慢光和快光，证明了通过流体和热驱动在单波长处控制群速度的可能性。
