为了得到光纤激光器的好的调制特性，对光纤激光器的偏振态控制与否进行了对比试验，发现激光器没有进行偏振态控制，调制后的信号为噪声，即无法调制；利用扭转光纤控制构成腔的偏振态，选频器采用保偏光纤上写入的光纤光栅研制的环形激光器，调制特性可以与半导体激光器相比拟。比较了利用半导体激光器与偏振态控制的光纤激光器100km传输实验结果，二者结果一致。研究结果有利于光纤激光器在光纤通信中的应用。

Modulation is a key technology of a fiber laser. Without polarization control,the laser is unable to be modulated.With strictly polarization control,a novel structure of stabile fiber laser was set up. The fiber laser was made of a twisted normal and Er-doped fiber and could be modulated well. The modulated laser was already used in an over 100km single mode fiber fiber transmission system. The result is accordance with that of the transmission system by using semiconductor laser.