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Note: Section A is compulsory. Attempt any four questions each carrying 5 marks from section B and any two each carrying 10 marks from section C.


Section A (10 x 2 = 20)
1.
How is light guided through optical fibres?
What are optical fibres immune to?
How is characteristic value for the fibre and the attenuation of optical fibres related?
What is dispersion?
List the components of optical fibre communication
What is a step-index multimode fibre?
Which type of fibre has the highest modal dispersion?
How is light emission from an LED modulated?
What is a pin photodiode?
Define fibre refractive index.

Section B (4 x 5 = 20)

2. Discuss the Electromagnetic mode theory for optical propagation.

3. Explain the measurement procedure for Fibre attenuation and fibre diameter.

4. Discuss the modulation of laser diodes.

5. Describe the principles of optical detection.

6. Explain the optical transmitter circuit.

Section C (2 x 10 = 20)

7. Describe with examples the various types of losses in optical fibre transmission.

8. Discuss the LED structure, characteristics, efficiency and modulation process.

9. Write notes on:
(a) Photodiode materials
(b) Optical receiver circuit