Light travels in straight lines, even though lenses and mirrors can deflect it, light still travels in a straight line between optical devices. This is fine for most purposes; cameras, binoculars, etc. wouldn't form images correctly if light didn't travel in a straight line. However, there are times when we need to look round corners, or probe inside places that are not in a straight line from our eyes. That is why "FIBRE OPTICS" have been developed.
The working of optical fibres depend on the basic principle of optics and the interaction of light with matter. From a physical standpoint, light can be seen either as "Electromagnetic Waves" or as "Photons". For optics, light should be considered as rays travelling in straight lines between optical elements, which can reflect or refract (bend) them.
Light is only a small part of the entire spectrum of electromagnetic radiation. The fundamental nature of all electromagnetic radiation is the same: it can be viewed as photons or waves travelling at the speed of light (300,000 km/s) or 180,000 miles/sec).