The worldwide demand for communication has consistently increased over the past two decades i.e. from merely 64kbps in eighties to over 10Gbps today. These are primarily due to Globalisation. At present we are going through a global information revolution. The explosive growth of data, particularly internet traffic, has led to a dramatic increase in demand for transmission bandwidth. Also the ever evolving electronics has revolutionised the communication equipment which made it simpler and economic to deploy state of the art communication networks to meet the demands of society. Already the largest and extremely complex telecommunication networks have been deployed over the world. Traditionally, these networks only provide lines connecting various users. However, in future, the information services are expected to converge with multimedia services integrating voice, data, video and consumer electronics. This development has pushed the requirement of network capacity into Terabits/Sec range. This demand requires several orders of network capacity and flexibility than currently provided by conventional telecommunication networks.

Optical Communication has emerged as one of the most important technology to serve the world-wide demand of increased communication capacity. In principle, optical techniques offer low-loss transmission over thousands of kilometres. Moreover, the bandwidth offered by Optical fibres allows transmission of many different wavelengths simultaneously. This enables the communication spectrum to reach Terabit/sec level. Considering the immense technological capability provided by the Optical domain, it is evident to understand the nuances of the Optical Communication Systems and exploit it fully to meet the ever-increasing demands. Optical communication is truely becoming a modern age phenomenon by revamping not only telecommuncation industry but also other industries including entertainment, medicine, etc. It is touching everyone's life by some way or the other.


Today Optical Fibre is used for telephony, Internet, and cable television transmission. Earlier fibre-optic systems were complex and expensive to install and operate. Hence these were primarily deployed for long-distance transmissions only, where they can be used economically to their full transmission capacity. With rapid technological developments, the prices for fibre-optic communications have dropped considerably. This has resulted in cost-effective deployment of fibre to the home than copper-based network. Further it also provides added advantage of converged information services.

The optical fibers are used now days in a wide range of applications in metrology and medicine. Various applications in the Medicine field include surgery, endoscopy, and sensing. While the fiber design may be quite different when optimized for these applications, the general principles of operation remain much the same. The aim of this article is to know the capacity of a particular technology for effective exploitation. It just works on a simple principle of Total Internal Reflection.