The development of optical fiber amplifiers has spurred study of the 1R (reshaping) repeating transmission method for transmission distances over 1000 km. As transmission distances become longer, there is the possibility that polarization mode dispersion and chromatic dispersion will limit transmission distances. In particular, polarization mode dispersion can be altered by the ambient temperature, cable structure, and situation of installation. The effects of such factors with respect to the polarization mode dispersion in submarine optical fiber cables have not been sufficiently clarified. Therefore, in this article, the authors investigate the polarization mode dispersion by using a submarine optical fiber cable with 12 fibers roughly 10 km in length to clarify the characteristics of a submarine optical fiber cable for application in long‐distance transmission systems with optical fiber amplifiers. The results show that there is a correlation between the changes in the polarization mode dispersion after each cable manufacturing process and the change in the strain, as well as accompanying changes in lateral force. Finally, the temperature dependence (from 5 °C to 30 °C) of the polarization mode dispersion is also described. © 2000 Scripta Technica, Electron Comm Jpn Pt 1, 83(8): 76–84, 2000