椭圆偏振保持光纤消光比测量的研究

Investigation of Measurement of Extinction Ratio of the Elliptical Polarization-Maintaining Fiber

偏振消光比是衡量光偏振特性的重要参数之一,椭圆偏振保持光纤是一种重要的新型保偏光纤,可以保持某种特殊椭圆偏振态的不失真传输。对现有消光比的定义进行了拓展,使之适用于椭圆偏振保持光纤。提出了一种按照新定义测量消光比的方法,并使用剪断法对一根长20m的椭圆偏振保持光纤进行了消光比劣化的实验测量。实验结果表明,以最短余长2m消光比为参考值,被测光纤在截断余长为10 m、15 m和20 m时的消光比相对劣化值分别为0.168dB/m、0.154 9dB/m和0.165 5dB/m。由此可知,消光比的相对劣化值虽然与光纤长度有关但并不呈线性变化。

The polarization extinction ratio is one of the important parameters to measure light polarization characteristics.Elliptical polarization-maintaining fiber is an important new type of polarization-maintaining fiber,which can maintain a pair of some special orthogonal state of elliptic polarization to transmit to distance without distortion.In this paper,the definition of extinction ratio is extended in order to make it applied to elliptical polarization-maintaining fiber.A new measurement method of extinction ratio according to the novel definition is proposed and the deterioration of extinction ratio of the elliptical polarization-maintaining fiber is experimentally measured using cut method.The results indicate that,compared to the extinction ratio of left length 2 m of the fiber,the deterioration of extinction ratio is0.168 dB/m,0.154 9 dB/m and 0.165 5 dB/m for left length 10 m,15 m,and 20 m,respectively,and show that the deterioration of extinction ratio is dependent of the fiber length,but not linearly changing with fiber length.