Other Bachelor Degree- FIBER OPTICS AND LASER INSTRUMENTATION (Karunya University, Coimbatore-2010)
Saturday, 24 August 2013 07:39anudouglas
Karunya University
(Karunya Institute of Technology and Sciences)
(Declared as Deemed to be University under Sec.3 of the UGC Act, 1956)
End Semester Examination – November/December 2010
Subject Title: FIBER OPTICS AND LASER INSTRUMENTATION Time: 3 hours
Subject Code: 09EI203 Maximum Marks: 100
Answer ALL questions
PART – A (10 x 1 = 10 MARKS)1. Define radiance of an LED.
2. Calculate the Brewster angle for glass.
3. Name different types of mode locking.
4. What is the wavelength emitted by He-Ne laser?
5. What kind of change can be measured by an all-fiber interferometer?
6. What are the different types of modulators?
7. Name the field in which dye lasers are used.
8. Laser range finders use ____________ lasers.
9. What are the principle uses of lasers in medical surgery?
10. List two uses of holography.
PART – B (5 x 3 = 15 MARKS)
11. A step index fiber has a core with a refractive index of 1.50 and a cladding of refractive index 1.48. Calculate the numerical aperture and its critical angle.
12. What is the optical time domain reflectometry?
13. Distinguish between spontaneous and stimulated emission.
14. Mention the uses of LIDAR.
15. Give the advantages of using lasers over conventional surgery.
PART – C (5 x 15 = 75 MARKS)
16. a. Distinguish between a step index fiber and a graded index fiber. (3)
b. Explain the different types of signal attenuation (fiber loss) in single mode fibers. (12)
(OR)
17. a. Define carrier life time of an LED (3)
b. Discuss in detail the two basic structures of LED. (12)
18. Name the classification of fiber optic sensor based on the scheme of modulation. Explain them in detail.
(OR)
19. Explain with neat sketch the industrial application of fiber optic sensors.
20. With neat sketch explain the working of any one solid state laser and gas laser. Give their energy level diagram also.
(OR)
21. a. A GaAlAs laser diode has 300 µm cavity length which has absorption coefficient 10 cm-1 reflectivity of the reflector are 0.8 and 0.6 respectively.
i) What is optical gain?
ii) If the internal quantum efficiency is 0.65.What is the external quantum efficiency?
(8)
[P.T.O]
b. Calculate the pulse width produced by a mode lock Nd gas laser assuming that the laser cavity is 0.2 m long and that there are 3000 participating longitudinal modes. What is the time separation of the pulses? (7)
22. Explain in detail the uses of lasers in material processing in industries.
(OR)
23. Describe the measurement of distance and atmospheric effect using laser.
24. a. With neat schematic diagram explain how a three dimensional effect is created. (10)
b. How can you measure blood velocity using a fiber optic catheter and a laser? (5)
(OR)
25. a. Explain any one type of holographic interferometer. (10)
b. Suggest medical applications of laser. (5)
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