中文摘要：

在密集波分复用（DWDM）系统中进行多信道色散补偿时，需要把多个光纤光栅串联在一起使用，这样连接在后面的光纤光栅的插损会因为背景损耗的存在而随着光纤光栅数量的增加而增大，尤其是波长较多的时候，接在最后的信道的插损会显著增大，这将制约光纤光栅的最大连接数。通过实验探讨了光纤的紫外曝光造成的背景损耗对串联的窄带啁啾光纤光栅的影响以及对光纤光栅最大连接数的限制。

英文摘要：

When multichannel dispersion compensation is made in the dense wavelength division multiplexing （DWDM） systems, many fiber gratings are needed to be concatenated together. The insertion loss of gratings will increase due to the background loss as increasing of the number of gratings. Especially when the number of channels is large, the last channel insert loss gets larger obviously, which limits the maximum of the amount of the gratings concatenated together. The maximum number of the concatenated chirped fiber gratings is investigated through the experiment about measuring the background loss of the photosensitive fiber induced by ultraviolet light exposure.