利用高频CO2激光脉冲写制了倾斜长周期光纤光栅(TLPFG)，运用改造的耦合模理论对基于高频CO2激光脉冲写制的TLPFG进行了理论分析，实验研究了倾斜折射率调制对TLPFG光谱特性的影响，分析了倾斜角度对TLPFG模式耦合特性的影响。实验结果表明,利用高频CO2激光脉冲写制的TLPFG具有新颖的耦合特性，低阶次包层模的耦合系数大于高阶次包层模，倾斜折射率调制不仅可以提高纤芯基模与包层模的耦合系数，还可以激励纤芯基模向高阶包层模式耦合，且随着倾斜角的增大可以明显提高光栅的写制效率。

A novel tilted long-period fiber grating (TLPFG) written by high-frequency CO2 laser pulses was experimentally demonstrated. The coupled-mode theory was modified in order to theoretically analyze the TLPFG. The effects of tilted refractive index modulation on the spectral properties of the TLPFG were studied. The influence of tilted angle on the modes coupling of TLPFG was analyzed. Theoretical analysis is in accord with experimental results. The experimental results show that the TLPFG written by high-frequency CO2 laser pulses has many novel properties. The coupling coefficient of low-order cladding modes is higher than that of high-order ones, and tilted refractive index modulation not only can enhance the coupling coefficient between the core fundamental mode and cladding modes, but also can stimulate the coupling between core fundamental and high-order cladding modes. The written efficiency can be dramatically improved by increasing the tilt angle.