基于宽光谱应用的波长解复用多重体光栅的光写入特性

针对光通信中波长覆盖范围日益增宽的特点，从理论上研究了用于宽光谱范围波长解复用器件的多重体光栅的布喇格匹配和各波长对应光栅衍射效率的均匀性.计算及实验结果均表明，由于记录介质的色散效应将导致多重体全息光栅读出过程中明显的布喇格失配，并且在写入过程中获得的均匀折射率调制度的多重体光栅，在读出过程中各通信波长对应光栅的衍射效率将不均匀为此，提出了改进多重体光栅的光写入方法，给出了利用角度复用法写入透射型多重体光栅时解复用波长与写入角度的关系，以及写入体光栅过程中记录介质的折射率调制度修正公式.

The Write-in Characteristics of Multiple Volume Holographic Gratings for Wavelength Demultiplexing with wide Spectra

The Bragg matching and the uniformity of Bragg diffraction efficiencies of multiple volume holographic gratings (MVHGs), which were used for wavelength demultiplexing devices in optical communication based on all wave optical fiber, were theoretically studied and quantitatively analyzed. It was shown that the Bragg mismatching would be caused due to the recording medium dispersion during wavelength demultiplexing with wide spectra by employing MVHGs. Moreover the Bragg diffraction efficiencies of MVHGs with homogeneous refractive index modulation obtained at short writing wavelength would not be uniform at different optical communication wavelengths. And it has been experimentally demonstrated. For this reason, the improved dependence of writing angles on communication wavelengths for fabricating angle-multiplexing transmission MVHGs and the corrected formula for refractive index modulation of individual MVHG at writing wavelength were presented in order to ensure rigorous Bragg matching and the uniformity of diffraction efficiencies.