SEMICONDUCTOR PHYSICS AND OPTO ELECTRONICS

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SEMICONDUCTOR PHYSICS AND OPTO ELECTRONICS

ANNA UNIVERSITY :: CHENNAI - 600 025

MODEL QUESTION PAPER

B.E. DEGREE PROGRAMMES

PH 136 - SEMICONDUCTOR PHYSICS AND OPTO ELECTRONICS

Time: 3hrs   Max Marks: 100

Answer all Questions

PART - A (10 x 2 = 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 different 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 required to record a hologram?


PART - B (5 x 16 = 80 Marks)


11.   

(i)    Explain the processes 'Analog Modulation' and 'Digital Modulation' with figures. (4 + 4)

(ii)    Describe the construction and working of a electro optic amplitude modulator. (8 )

12 .a)    Derive an expression for density of states and hence calculate the carrier concentrations in metals and semiconductors.

(OR)

12.b)

(i)    What are the advantages of photoconductive mode? (2)

(ii)    Describe silicon photodiode structure for photoconductive operation. (10)

(iii)    Write the main factors that limit the speed response of photodiodes. (4)


13.a)   

(i)    Describe the action of LCD display device in reflection mode. (6)

(ii)    Describe two methods of connecting an array of display elements. (6)

(iii)    What are the advantages and disadvantages of LCDs? (4)

(OR)

13.b)   

(i)    Why electronic chip has to be packaged properly at various stages before its use? (4)

(ii)    Draw and explain the structure of a typical chip carrier. (8 )

(iii)    What are Multilayer Multi Component substrates? (4)
14.a)   

(i)    What are single mode and multi mode fibers? (4)

(ii)    Derive an expression for numerical aperture of the fiber. (8 )

(iii)    Calculate 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)    Explain with a schematic diagram an optical communication system. (6)

(ii)    What is attenuation and how signal amplification is done in fibers? (6)

(iii)    Write different attractive features of fiber optic communication. (4)
15.a)   

(i)    Explain the design and data storage system of a floppy disk and a magnetic tape. (5 + 5)

(ii)    Explain 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)    Explain the construction and reconstruction of a hologram with neat sketches. (6 + 6)