**4. Summary**

The occurrence of birefringence in commercially optical fibers is influenced by internal and external factors such as bending and tension forces. This, therefore, changes the cores from circular to ellipses and *vice versa* and this makes light waves experienced an elliptical or circular polarization to produce two waves in different phases. Moreover, SMF 28 ULL was discovered to have the highest birefringence value while the lowest was recorded at SMF 28e + LL. Birefringence can cause PMD. SMF 28 has the largest PMD value with a value of 0.69770237 ps compared to other optical fibers and this consequently led to a large pulse widening at cladding with a low bit rate.

## **Author details**

Toto Saktioto\*, Yoli Zairmi, Sopya Erlinda and Velia Veriyanti Universitas Riau, Pekanbaru, Indonesia

\*Address all correspondence to: saktioto@yahoo.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
