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基于sinc切趾反射体布拉格光栅的谱合成技术是获得高功率谱合成输出的有效方法。考虑到入射单色平面波光束的偏振状态,采用传输矩阵法,分析了光栅参数对衍射效率、波长选择性和角度选择性的影响。计算结果表明,入射角度对不同偏振状态入射光束的衍射效率影响较大。sinc切趾反射体布拉格光栅的衍射效率近似由光栅厚度和折射率调制幅值的乘积决定,当折射率调制幅值与光栅厚度的乘积大于1.7028×10-6时,不同偏振态在小角度入射时的衍射效率高于99%。sinc切趾反射体布拉格光栅的波长选择性带宽和角度选择性带宽随折射率调制幅值的增加而增大,随衍射效率的增加而减小。通过优化光栅参数,利用sinc切趾体布拉格光栅可实现光谱间距低于200 pm的多光束谱合成。
Spectral synthesis based on sinc apodized reflector Bragg grating is an effective method to obtain high-power spectral synthesis output. Taking into account the polarization state of incident monochromatic plane wave, the influence of grating parameters on the diffraction efficiency, wavelength selectivity and angle selectivity are analyzed by the transfer matrix method. The calculated results show that the incident angle has a great influence on the diffraction efficiency of incident beams with different polarization states. sinc apodized reflector The diffraction efficiency of a Bragg grating is approximately determined by the product of the thickness of the grating and the amplitude of the refractive index modulation. When the product of the amplitude of the refractive index modulation and the thickness of the grating is greater than 1.7028 × 10 -6, different polarization states are incident at a small angle The diffraction efficiency is higher than 99%. The wavelength-selective bandwidth and the angle-selective bandwidth of sinc apodized reflector Bragg grating increase with the increase of refractive index modulation amplitude and decrease with the increase of diffraction efficiency. By optimizing the grating parameters, multi-beam spectral synthesis with spectral spacing below 200 pm can be achieved using sinc apodized Bragg gratings.