Numerical Investigation and Optimization of SBS-Based Slow-Light Using Filtered Incoherent Pump

The performance of stimulated Brillouin scattering （SBS）-based slow light using a novel spectrally-sliced broadband incoherent pump source is numerically studied. The profile of the pump-power spectrum is determined by the transmission spectra of the optical filter followed by the polarized broadband incoherent pump source. We also investigate the performance of Gaussian-type and super-Gaussian-type filtering under different spectrally-sliced
bandwidths and pump power levels for 2.5Gbit/s return-to-zero pulse （50% duty-cycle）. The pulse broadening is characterized by the full width of half maximum （FWHM） and the rms pulse width, respectively. However,the results obtained by the two kinds of measurement methods deviate from each other with increasing pump power. Compared with the regular Gaussian-type filtering, the pulse broadening can be significantly reduced using super-Gaussian-type filtering at the cost of a small reduction in delay time. Furthermore, the maximum improvement in pulse broadening of ＆#8710; BFWHM =28.4% and ＆#8710; B RMS =10.4% is achieved by using a five-order super-Gaussian-type filter and a pump power of 500mW.     

基于LOA的XGM全光波长转换消光比特性的研究

建立了线性光放大器(LOA)的交叉增益调制(XGM)波长转换理论模型.着重讨论了抽运光与探测光的波长和功率、LOA中分布式布拉格反射镜(DBR)的反射率和注入电流等参量对输出消光比特性的影响.结果表明,输出消光比随着抽运光(探测光)波长的增加而增加(减小);适当的减小探测光功率和选择合适的注入电流可以获得较大的消光比;波长向下转换时的消光比明显优于向上转换时的消光比;同样,提高LOA中DBR的反射率,也可以获得较高的消光比.     

二维三角晶格介质柱光子晶体线缺陷波导慢光研究

以二维三角晶格介质柱光子晶体线缺陷波导为研究对象,通过平面波展开(PWE)法对光在波导中传输时的慢光特性进行了仿真分析,发现光子晶体的填充因子以及线缺陷中的柱子半径大小决定了慢光导模在光子带隙中的传输特性.随着填充因子的增大,光子晶体波导的导模群速度迅速减小.缺陷柱的半径大小对导模群速度的影响要强于填充比.通过调整填充因子和缺陷柱半径,得到了导模群速度小于0.01c的波导结构.结合慢光导模的群速度色散(GVD)特性分析,发现极慢光区域的GVD值位于105～106量级,能够保证光的高效传输.     

基于匹配滤波解调的多芯Bragg光栅曲率传感器

设计了一种多芯光纤Bragg光栅曲率传感器,并采用匹配滤波技术实现曲率解调。多芯光纤Bragg光栅曲率传感器是通过在多芯光纤的两个中心对称纤芯中写入Bragg光栅实现的。两个光纤Bragg光栅具有相似的反射谱和中心波长,当多芯光纤发生弯曲时,两个光纤Bragg光栅的反射谱叠加区域将发生改变。将两个光纤Bragg光栅构造成匹配滤波模式,则两个光纤Bragg光栅反射谱的叠加区域面积决定了输出信号的光强,而叠加区域的面积与光纤曲率有关。因此,通过测量匹配滤波信号的功率可以实现曲率解调。结果表明,匹配滤波技术能有效解调多芯光纤Bragg光栅曲率传感器,最大曲率解调灵敏度为0.78mW·m~(-1)。此外,测量了多芯光纤Bragg光栅曲率传感器在不同轴向应变和环境温度下的解调性能,结果表明,该曲率解调系统具有很强的抵抗外界环境波动的能力。