理论上分析并从实验上验证了一种利用均匀相位掩模板写入啁啾光纤光栅的方法:将光纤弯曲,由于光纤离掩模板的距离不同从而使光纤光栅的周期轴向渐变,由此产生啁啾。分析了这种啁啾光纤光栅的谱特性和时延特性,同时也分析了由于光纤离掩模板的距离不同而引起的折射率调制变化给光纤光栅特性带来的影响。设计了一种石英曲面,利用其使光纤按照弯曲函数进行弯曲,然后进行紫外曝光制成了线性的啁啾光纤光栅。实验中制作的啁啾光纤光栅色散值为-1102 ps/nm,纹波为17ps。通过改变弯曲函数就可以实现利用一块均匀相位掩模板制作不同啁啾量的啁啾光纤光栅的目的,降低了啁啾光纤光栅的制作成本。

A novel linearly chirped fiber grating was analyzed and fabricated by using uniform phase mask instead of chirped mask. The chirp of the grating is realized by precisely setting the distance between the fiber and the phase mask at every point of the fiber. The spectral characteristic and delay characteristic of such a chirped fiber grating were analyzed. And the influence on the grating by refractive index modulation variation caused by the variation of distance between the fiber and phase mask was also analyzed. In experiments we derived linearly chirped fiber grating by putting the fiber on the curved face behind the uniform phase mask to get ultraviolet light exposure. The fabricated chirped fiber grating has -1102 ps/nm dispersion, and time delay ripple of 17 ps. Gratings with different chirp with one uniform phase mask conveniently by only changing the curve function of the fiber, can be fabricated.