What is free space optical communication technology (FSOC)? Discuss its merits and challenges.
Demand of the Question: Introduction – Define FSOC technology. Give its context.
Body -Discuss the merits of FSOC technology. Highlight on challenges of FSOC technology. Conclusion – Conclude with need for FSOC technology for India.
Free Space Optical Communication (FSOC) technology is an optical communication technology in which data are transmitted by propagation of light in free space allowing optical connectivity without the requirement of the optical fibre cable. Working of FSOC is similar to OFC (optical fiber cable) networks. FSOC system consists of an optical transceiver at both ends to provide full duplex (bidirectional) capability. Andhra Pradesh government has signed Memorandum of Understanding (MoU) with Alphabet Inc.’s X (Google X) to bring FSOC technology to India.

  1. FSOC is a flexible network that delivers better speed than broadband.
  2. Installation is very easy and has very low initial investment.
  3. It is a straight forward deployment system. There is no need for spectrum license or frequency coordination between users as it is required in radio and microwave systems previously.
  4. It is a secure system because of line of sight operation and so no security system upgradation is needed.
  1. High data rate can be obtained which is comparable to the optical fiber cable data rate but error rate is very low and the extremely narrow laser beam enables having unlimited number of FSOC links which can be installed in a specific area.
  2. There is immunity to radio frequency interference. Electromagnetic and radio-magnetic interference cannot affect the transmission in FSOC link.
  3. FSOC offers dense spatial reuse. Low power usage per transmitted bit is merit of FSOC system.
  4. There is relatively high bandwidth. It has flexible rollouts. Transmission of optical beam is done in air. Hence, transmission is having speed of light.
    CHALLENGES OF FSOC TECHNOLOGY 1. Physical obstructions: flying birds, trees, and tall buildings can temporarily block a single beam, when it appears in line of sight (LOS) of transmission of FSO system. 2. Scintillation: Temperature variations, among different air packets due to the heat rising from the earth and the man-made drives like heating ducts, can cause fluctuations in amplitude of the signal which causes “image dancing” at the FSOC receiving end. 3. Geometric losses: Optical beam attenuation are induced due to the spreading of beam and reduced the power level of signal as it travelled from transmitted end to receiver end. 4. Absorption: Caused by the water molecules which are suspended in the terrestrial atmosphere. The power density of the optical beam is decreased and the availability of the transmission in a FSO system is directly affected by absorption. Carbon dioxide can also cause the absorption of signal. 5. Atmospheric turbulence: Due to weather and environment structure. It is caused by wind and convection which mixed the air parcels at different temperatures. This causes fluctuations in the density of air and it leads to the change in the air refractive index. Turbulence can lead to degradation of the optical beam of transmission. Change in the refractive index causes refraction of beam at different angle and spreading of optical beam takes place. 6. Atmospheric attenuation: It is the resultant of fog and haze normally. It also depends upon dust and rain. 7. Scattering: scattering phenomena happen when the optical beam and scatterer collide. It leads to the reduction in the intensity of beam for longer distance.
    Given that less than 20% of people in Andhra Pradesh currently have access to broadband connectivity, the state government has committed to connecting 12 million households and thousands of government organizations and businesses by 2019 – an initiative called AP Fiber Grid. FSOC technology is having significant role in that regard.

How has India benefited from the contributions of Vikram Sarabhai and A.P.J Abdul Kalam in the field of Space science and technology?
Demand of the Question:
Introduction: Introduce with status of Space program in India
Body: Write the contribution of Vikram Sarabhai
Write the contribution of APJ Abdul Kalam in defence and space technology
Conclusion: As per context
India’s space program has come a long way since its initiation and today it is making giant leaps to the moon, Mars and beyond. India also holds the honour of launching most number of satellites in a single mission. This success could not have been achieved without the contribution of Dr Vikram Sarabhai and Dr A.P.J. Abdul Kalam in the field of space science.

  1. Vikram Sarabhai was a physicist, industrialist, innovator and institutional builder. He was the founder of ISRO (Indian Space Research Organisation) and is known as the Father of the Indian Space Program.
  2. He established Physical Research Laboratory (PRL) in Ahmedabad on 11 November, 1947 which was the first laboratory of independent India. The institute became leading organisation of cosmic rays and space sciences in India.
  3. He started a project for the fabrication and launch of an Indian Satellite. And as a result, the first Indian satellite, Aryabhata was put into the orbit in 1975 from a Russian Cosmodrome.
  4. Vikram Sarabhai with help from Dr Bhabha set up the first rocket launching station at Thumba on the coast of the Arabian Sea.
    ● As a scientist, Dr. Kalam made an effort to develop the Polar SLV and SLV-III which injected the Rohini satellite in the near-earth orbit in July 1980 making India an exclusive Space Club member
    ● In the 1970s, Dr. Kalam also directed two projects, namely, Project Devil and Project Valiant, which sought to develop ballistic missiles from the technology of the successful SLV programme.
    ● Dr. Kalam took up the responsibility of developing guided missiles at Defence Research and Development Organisation as chief executive of Integrated Guided Missile Development Programme in 1982. He was responsible for the development and operationalising of AGNI and PRITHVI Missiles.
    ● Popularly called the “Missile Man” of India, Dr APJ Abdul Kalam rose from humble beginnings and earned the reputation of being the “people’s President” who endeared himself to all sections.

Dr Sarabhai as chairman of the Atomic Energy Commission played a crucial role in India’s journey in developing nuclear technology. He was responsible for the establishment and development of nuclear power plants. Dr. Sarabhai was instrumental in establishing institutions such as: Uranium Corporation of India Limited (UCIL) and Faster Breeder Test Reactor (FBTR), Kalpakkam Dr. Kalam was the man behind the weaponization of strategic missile systems and the Pokhran-II nuclear tests in collaboration with DAE, which made India a nuclear weapon State
Dr Sarabhai played a critical role in establishing Indian institute of Management (IIM), Ahmedabad, Centre for Environmental Planning and Technology University, Nehru Foundation for Development in 1965 which focus on the current problems of society and individual development and Vikram A. Sarabhai Community Science Centre (VASCSC) in 1960s with an aim to promote science and mathematics education among students and the general public.
Similarly, Dr. Kalam had brilliant and dominant personality and he was a man of vision, who always had novel ideas for the development of the country. He served as the 11th President of India and due to his contribution as an educationist his birthday is celebrated as World Students’ day. His guidance and contribution has helped the country to move ahead on the path of becoming a leader in the domain of Science.


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