Jawaharlal Nehru Technological University Hyderabad 2005-2nd Sem B.Tech Applied Electronics and Instrumentation III Supplementary s, ember/ember OPTO ELECTRONIC & LASER INSTRUMENTATION - Ques- exam paper

Code No: RR321002 Set No. 3
III B.Tech II Semester Supplementary Examinations,
November/December 2005
OPTO ELECTRONIC & LASER INSTRUMENTATION
(Electronics & Instrumentation Engineering)
Time: three hours Max Marks: 80
ans any 5 ques.
All ques. carry equal marks
? ? ? ? ?
1. (a) discuss the historical development of optical fibers with the help of Electro-
magnetic spectrum.
(b) Draw a graph showing the refractive index distribution of central core cladded
optical fibre and discuss the plot. [8+8]
2. (a) Compare Optical fiber communication system with Microwave communication
system.
(b) explain about the different applications of optical fibers in detail. [8+8]
3. (a) find rate formula for 2 level system.
(b) In aruby laser ?0 = 6943 0A , tsp= 3*10-3sec, n0 = 1.76,d = 5cm, r1 = r2 =
0.9, a1= 0, g(?0)=1.1*10-12sec. obtain threshold inversion, tc and
?. [6+10]
4. (a) define the working of Moire-fringe modulation fiber optic sensor.
(b) Differentiate ranging from an intensity modulated sensor and interferometric fiber
optic sensor. [8+8]
5. (a) Differentiate ranging from an extrinsic and intrinsic fiber optic sensor.
(b) define the arrangement and working of an optical fiber liquid level detector.
(c) discuss how the above sensor is superior over the other liquid level sensors.
[5+5+6]
6. With neat diagrams explain:
(a) Lasers in precision length measurement.
(b) Lasers in velocity measurement. [8+8]
7. (a) discuss the terms coherence requirements, resolution in connection with holo-
gram?
(b) With the help of neat sketches discuss the recording mechanism of hologram?
[8+8]
8. (a) Differentiate ranging from Magneto - optic and Acusto - optic modulators.
(b) Why acousto - optic modulators have to be used at low acoustic frequencies.

Earning:   Approval pending.