The Digital India initiative has been launched with a view to bridging the digital gap between the urban and rural parts of the country. A vital component of the programme is the National Optical Fibre Network (NOFN) project, which aims to extend the optical fibre cable (OFC) network to gram panchayats and facilitate the delivery of a host of services in education, health care, banking and agriculture, among other areas.

In government schools, broadband connectivity can be used to make the concept of digital classrooms a reality. Education can be imparted by adopting methodologies like audio-visual modules, animation and remote learning. On the back of a strong OFC network, educators can derive real value from virtual classrooms and provide vocational training to thousands of rural youth through e-learning content that covers a range of skills. Health care is another key area where broadband connectivity can be leveraged to run commercial telemedicine centres, which can be operated by private health care providers for delivering quality medical advice to the doorsteps of rural patients. Banking is another big segment that stands to benefit from an extended OFC network, as unbanked sections of the population can be reached through a third-party backbone network. Such a model is led by a third-party service provider who acts as the business correspondent for the banks. This model is already operational in India and can be extended to unconnected regions through the NOFN. Like education and health care, the banking system can also witness revolutionary developments with the introduction of services on the OFC network. Through agricultural knowledge hubs, government and private players can train and empower rural entrepreneurs who work closely with farmers. The network can also be used to deliver e-agriculture desktop and mobile applications developed by technology providers in partnership with other players in the agriculture value chain.

Among the various applications supported by OFC, there is a growing demand for video-on-demand (VoD) applications globally as well as in India. The global VoD market had been valued at $200 million in 2014, which is expected to increase to $357 million by 2020. In India, too, consumers are taking to VoD services heavily, with online video consumption in the country almost doubling in the past two years. Some of the key factors driving VoD consumption in India are the growing number of internet users, the proliferation of connected devices, and increased consumer spending on video services. The main advantages of VoD include the availability of more choice in terms of content and the flexibility of anywhere, any time access.

Given the growing demand for VoD services, the OFC network is being used extensively as it supports the high broadband connectivity that is required to deliver anywhere, any time content. Industry players can choose from a number of OFC technologies to support high speed networks, with some of the popular ones being:

• All-optical communication networks: In such networks, all signals are processed in the optical domain without any form of electrical manipulation.
• Multi-terabit optical networks: Dense wavelength division multiplexing technology paves the way for multi-terabit transmission. The worldwide need for increased bandwidth availability has led to interest in developing such networks.
• Intelligent optical transmission networks: These are networks of the future with capabilities like traffic engineering, dynamic resource route allocation, special control protocols for network management, scalable signalling capabilities, bandwidth on demand, wavelength rentals, wavelength wholesale, differentiated services for quality of service norms, and so on.
• Ultra-long-haul optical transmission: The cancellation of dispersion effects has prompted researchers to study the potential benefits of solution propagation. An in-depth understanding of the interactions between electromagnetic light waves and the transmission medium is necessary to proceed towards an infrastructure with the most favourable conditions for the propagation of a light pulse.
• High-altitude platforms: High-altitude platforms are airships that are situated above the clouds at heights of 16 to 25 km, where the unfavourable atmospheric impact on a laser beam is less severe than when it is directly above the ground. Optical links between high-altitude platforms, satellites and ground stations are expected to serve as broadband backhaul communication channels, if a high-altitude platform functions as a data relay station.

Going forward, the exponential demand for data services and the encour-aging demand for smartphones will lead the government and operators to make significant investments in OFC networks for delivering a wide array of applications in various domains.