Anna University Chennai 2007-6th Sem B.E Civil Engineering PH 13ICONDUCTOR PHYSICS AND OPTO ELECTRONICS - Question Paper

ANNA UNIVERSITY :: CHENNAI - 600 025
MODEL ques. PAPER
B.E. DEGREE PROGRAMMES
PH 136 - SEMICONDUCTOR PHYSICS AND OPTO ELECTRONICS

Time: 3hrs Max Marks: 100
ans all ques.
PART - A (10 x two = 20 Marks)
1. Calculate the number of atoms belonging to a unit cell of a face centered cubic (FCC) structure.
2. What are the desired characteristics of a photoconductive material?
3. What is Meissner effect?
4. What are the various applications of metallic glasses?
5. What is meant by electro absorption?
6. What is the general principle of a Self–Electro–optic Effect Device?
7. What are the conditions for total internal reflection to occur at the fiber walls?
8. What is soliton?
9. What are the advantages of CD?
10. What are needed to record a hologram?
PART - B (5 x 16 = 80 Marks)
11. (i) discuss the processes ‘Analog Modulation’ and ‘Digital Modulation’ with figures. (4 + 4)
(ii) define the construction and working of a electro optic amplitude modulator. (8)
12.a) Derive an expression for density of states and hence compute the carrier concentrations in metals and semiconductors.
(OR)
12.b) (i) elaborate the advantages of photoconductive mode? (2)
(ii) define silicon photodiode structure for photoconductive operation. (10)
(iii) Write the main factors that limit the speed response of photodiodes. (4)
13.a) (i) define the action of LCD display device in reflection mode. (6)
(ii) define 2 methods of connecting an array of display elements. (6)
(iii) elaborate the advantages and disadvantages of LCDs? (4)
(OR)
13.b) (i) Why electronic chip has to be packaged properly at different stages before its use? (4)
(ii) Draw and discuss the structure of a typical chip carrier. (8)
(iii) elaborate Multilayer Multi Component substrates? (4)
14.a) (i) elaborate single mode and multi mode fibers? (4)
(ii) Derive an expression for numerical aperture of the fiber. (8)
(iii) compute the acceptance angle of a fiber with a core index of 1.54 and a cladding index of 1.5. (4)
(OR)
14.b) (i) discuss with a schematic diagram an optical communication system. (6)
(ii) What is attenuation and how signal amplification is done in fibers? (6)
(iii) Write various attractive features of fiber optic communication. (4)
15.a) (i) discuss the design and data storage system of a floppy disk and a magnetic tape. (5 + 5)
(ii) discuss how the CDs are classified based on their storage technique and capabilities. (6)
(OR)
15.b) (i) What is holographic storage of information? (2)
(ii) What happens to the hologram when cut into pieces? (2)
(iii) discuss the construction and reconstruction of a hologram with neat sketches. (6 + 6)

Earning:   Approval pending.