The combination of laser and optoelectronics with optical fiber technology can enhance the seamless activities of fiber-optic communications and fiber-sensor arena. This book discusses foundations of laser technology, non-linear optics, laser and fiber-optic applications in telecommunication and sensing fields including fundamentals and recent developments in photonics technology. Accumulated chapters cover constituent materials, techniques of measurement of non-linear optical properties of nanomaterials, photonic crystals and pertinent applications in medical, high voltage engineering and, in optical computations and designing logic gates.