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

Code No: RR321002 Set No. 1
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) Briefly discuss about the optical fibre construction details and show a figure for
transmission of light rays and explain about the refractive index distribution
with a graph.
(b) Write the equations for the total internal reflection of the light rays in a optical
fibre cable and derive the expression for the Numerical Aperture of the fibre.
[8+8]
2. (a) provide any 3 applications of optical fibers for instrumentation and discuss
them with the necessary figures.
(b) Draw the block diagram of a typical fiber optic communication system and
discuss the function of every block in detail. [8+8]
3. (a) Estimate the number of photons emitted per 2nd from a laser that puts
out 1 watt of power. State clearly the assumptions made.
(b) define the degradation mechanism in injection lasers. [8+8]
4. (a) discuss how the Moire-Fringe modulation fiber optic sensor helps in eliminat-
ing the instability encountered with fiber optic intensity modulated sensor.
(b) With a neat diagram discuss the interferometric method of measurement of
length. [8+8]
5. (a) Differentiate ranging from a transducer and a sensor
(b) define the arrangement and working of an optical fiber liquid level detector.
[8+8]
6. With neat diagrams discuss the subsequent applications of lasers in detail :
(a) Lasers in material processing.
(b) Laser fusion in power plants. [8+8]
7. Write short notes on :
(a) Holograms on magnetic tape
(b) Holograms on the thermoplastic films. [8+8]
8. (a) Compare the performance characteristic of a p.i.n photodiode and p.n photo-
diode.
(b) Distinguish ranging from internal and external quantum efficiency.

Earning:   Approval pending.