Cuadrado-Laborde C, Andrés M V
Departamento de Física Aplicada y Electromagnetismo, Institut Universitari de Ciència dels Materials, Universidad de Valencia, Valencia, Spain.
Opt Lett. 2009 Mar 15;34(6):833-5. doi: 10.1364/ol.34.000833.
We demonstrate that an asymmetrical pi phase-shifted fiber Bragg grating operated in reflection can provide the required spectral response for implementing an all-optical fractional differentiator. There are different (but equivalent) ways to design it, e.g., by using different gratings lengths and keeping the same index modulation depth at both sides of the pi phase shift, or vice versa. Analytical expressions were found relating the fractional differentiator order with the grating parameters. The device shows a good accuracy calculating the fractional time derivatives of the complex field of an arbitrary input optical waveform. The introduced concept is supported by numerical simulations.
我们证明，一个工作在反射模式下的非对称π相移光纤布拉格光栅能够为实现全光分数微分器提供所需的光谱响应。有不同（但等效）的设计方法，例如，通过使用不同的光栅长度并在π相移两侧保持相同的折射率调制深度，反之亦然。已找到将分数微分器阶数与光栅参数相关联的解析表达式。该器件在计算任意输入光波形复场的分数时间导数时具有良好的精度。所引入的概念得到了数值模拟的支持。
