With the invention of the laser in the 1960's, a great opportunities and interest in the optical systems and data communication is begun. From that date on scientists and researchers are motivated to bring on some new applications in the field of fiber optics technology. The main reason of the book is, Giving a brief about the fiber optic Technology and how does it works. Studying the results of the applications and the advantages and disadvantages from using such a technology. Recent advances apps in fiber optics technology have a big impact in the telecommunication industry because of the ability to carry gigabits of information at the speed of light and to long distances that pushes the whole industry forward. In Parallel of this technology scientists have developed the fiber optic sensors which are used just lately in different fields. The usage of the fiber optics to monitoring environmental changes and that offer many advantages over the other kinds of sensors which are used in the monitoring applications.