Gowar's book is a substantial volume. Carrying it around is not practical for most students or professionals. A PDF, however, can be stored on a laptop, tablet, or even a smartphone. This means you can study at a coffee shop, refer to a diagram in a lab, or review a chapter on a commute—all without the physical bulk.
: Attenuation mechanisms and dispersion in single-mode and multi-mode fibers. optical communication systems john gowar pdf better
Covers attenuation, material dispersion, waveguide dispersion, and non-linearities. Gowar's book is a substantial volume