Investigation of Group Birefringence of Polarisation Maintaining Highly Birefringent Optical Fiber

In the paper there are presented results of an investigation of a group birefringence of a fabricated polarization maintaining highly birefringent optical fiber around the central wavelength 1550 nm. The value of group birefringence was determined in two experimental ways. The first experimental set-up uses a system based on fiber loop mirror and the second one is based on a standard polariscopelike geometry usually used for investigation of birefringence of any optically transparent anisotropic medium. In both cases the birefringence is determined by appropriate analysis of typical interference patterns measured by the particular setup. The measurement was performed for fiber samples with various lengths. Comparison between values obtained for various lengths of samples and resulting from interference patterns measured using different experimental set-ups shows a very good match.