理论分析了光纤光栅调谐量与光纤应力和拉伸系数间的关系，实验研究了环行腔掺铒光纤激光器的最佳输出耦合比、调谐波长与新型可调谐光纤光栅挤压长度的关系以及不同耦合比对激光线宽和调谐范围的影响。在最佳输出耦合比为9∶1时得到3．8mW最大激光输出功率，在耦合比为7∶3时最大调谐范围为7．85nm。

The connection among a tune range of wavelength and inner stress and elongation coefficient in the fiber grating is analyzed theoretically. A ratio of couple of optimal laser output and the relativity between the compress length of the fiber grating and the wavelength as well as the influence of line-width and a tune area of the laser spectrum at the different radio of couple to laser output are experimentally studied for ring and tunable doped-Er fiber grating. The best output power of the fiber laser is obtained when the radio of couple of laser output is 9 to 1,and the maximal tune range of wavelength of 7.85 nm is got when the radio of couple of laser output is 7 to 3.