[3] Hu Yongming, Tan Jichun, Chen Zhe et al.. Phase contrast method for measurement of birefringent axes orientation of polarization-maintaining fiber. Proc. SPIE, 1996, 2895: 350~354
[4] E. Hecht, A. Zahac. Optics. Addison-Wesley Publishing Company, Inc., U. S. A., 1974. 474~478