Maximum Marks:100 Time Allowed:3 hours
- Attempt 5 questions in all.
- All questions carry equal marks i.e 20.
- Select at least one question from each of the four units.
Q1. (a) What is the physical significance of numerical aperture in an optical Communication?
Derive an expression for calculating it. 10
(b) Explain the difference between step index & graded index fibers.
Discuss their applications in optical communication. 10
Q2. (a) Explain the importance of splices & connectors. Discuss different splicing
techniques in optical communication. 10
(b) Explain the steps involved in fusion splicing with the help of a suitable
Q3. What are the various types of losses in optical fibers? Explain in detail. 20
Q4. (a) What is dispersion? What are it’s various causes? 6
(b) What is the impact of dispersion on the transmission of signals in
optical fibers? 6
(c) Explain the process of inter modal dispersion in optical fibers. 8
Also derive the expression for pulse delay.
Q5. Explain laser action in detail.Also define the internal quantum efficiency
in led’s.Draw it’s spectral characteristics. 8+7+5
Q6. (a) Explain the constructional aspects of an optical fiber communication
systems.Draw the detailed block diagrams of transmitter & receiver
(b) Explain one technique for coherent & non-coherent detection. Also
define the response of a photo detector. 10
Q7. (a) What are photonic networks? Discuss them as an alternative for future. 10
(b) Write 8 differences between single hop & multiple hop networks. 10
Identify this network
Q8. (a) In what way is light coupled in the case of optical fibers? Discuss the
functioning of various optical couplers. 12
(b) Write short notes (any two) 8
Wavelength division multiplexer