MEASUREMENT OF POLARIZATION FLUCTUATIONS IN INSTALLED SINGLE-MODE OPTICAL FIBER CABLES

Measurements were made of the random polarization fluctuations of conventional single-mode fibers of five optical fiber cables installed in the city of West Berlin, Federal Republic of Germany. The measurements were performed with the aid of a semiconductor laser, the frequency (f) of which was 227. 3 THz (wavelength 1320 nm). Such preliminary studies are very important for optically coherent transmission over cables not maintaining the polarizations. The signal intensity fluctuations as the fiber output can be represented both as a function of time and by the related spectral power density.