EC6016 OPTO ELECTRONIC DEVICES

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING QUESTION BANK SUB. NAME: OPTOELECTRONIC DEVICES SUB.CODE : EC6016

YEAR/SEM: IV / VII DEPT :ECE

UNIT I ELEMENTS OF LIGHT AND SOLID STATE PHYSICS PART-A (2Mark Questions) 1. Define uncertainty principle of Quantum mechanics. 2. State and Explain Bragg’s Law in Diffraction 3. What is meant by doping and how will you get n type Semiconductors? 4. Define wave front. 5. Define refractive index. 6. What are the two kinds of polarization? 7. What is Hetero junction material? 8. What do you understand wave particle Duality of Light 9. Give the expression for wave nature of light. 10. Define Brewster angle. 11. What do you meant by interference? 12. What is meant by Diffraction? 13. Define the term wave front. 14. What are light sources and name the different types of Light sources. 15. What is black body sources 16. What is line sources 17. What do you understand by the quantum mechanical concepts 18. What do you meant by semiconductor and name the different types of semiconductor? 19. What is intrinsic semiconductor? 20. What is Extrinsic semiconductor? 21. Differentiate Intrinsic and Extrinsic Semiconductor. 22. What are miller indices of crystal? 23. Differentiaate Diffraction and Scattering. 24. The average electric field in a particular 2.0 µm GaAs device is 5KV/CM. calculate the average velocity of electron if its mobility value is 8000 CM2/V-S 25. What is meant by polarization 1. Derive and explain in detail the Schrödinger’s wave equation

(16)

2. Derive the electron energy in one electron atom using wave equation

(16)

3. Describe in detail the position of Fermi level in semiconductor at equilibrium

(16)

EC6016 OPTO ELECTRONIC DEVICES 4. Explain in detail about Hall Effect

(16)

5.Explain the various parameters and characteristics of semiconductor Hetero junction materials 6.Derive Bragg’s law in X-ray diffraction. 7.Discuss the powder method of crystal structure analysis.[NOV/DEC-12] 8.Describe with the help of experimental set up, how will yow determine the nature of a semiconductor using Hall Effect. 9.Describe the crystal structure of silicon and Ga As? 10. Explain the energy values of electrons in a metal.[NOV/DEC-13] 11. How does the electrical conductivity of extrinsic semiconductors vary with temperature &impurity addition? 12. Explain the frequency response of silicon photodiodes using a suitable graph. [JUNE-12] 13. Derive the De Broglie wave Equation.

(4Marks)

14. Describe with the Experimental setup, the Davisson –Germer experiment to prove the wave nature of matter. 15. Derive the expression for Concentration of Electrons and Holes in an intrinsic Semiconductor, with relevant Diagram (16 marks) 16. Explain the principle of superposition and hence derive an expression for maximum irradiance resulting from four coherent Sources.

(10)

17. With a neat diagram explain the interference effects in a thin film of refractive index “n” (6) 18. Discuss about Drift and Diffusion of carriers with relavent mathematical expression(4 marks) 19. A plane wave is incident at the angle of 36 degree to the normal from a medium with E1 = 6.0 Eo on an interface with a medium with E2 = 13.0 Eo. Obtain the Reflection and Transmission coefficients for TE and TM polarized assuming the two media to be non magnetic. (16marks) 20. Determine the density of states of a 3D system at a energy of 0.1 eV if the effective mass is mo. (10marks) 21. What is optical Confinement Factor ?Explain

(6marks)

EC6016 OPTO ELECTRONIC DEVICES UNIT- II DISPLAY DEVICES AND LASERS PART-A (2Mark Questions) 1. What are the types of LED? 2. What is stimulated emission time? 3. Define Population inversion. 4. What is Mode locking of Laser? 5. Define DBR (Distributed Bragg Reflector) Laser. 6. What is threshold condition for Lasing? 7. What is the necessary condition for Lasing? 8. What is LED? 9. What is a cryotron? [ MAY-13] 10. What are liquid crystals?[MAY-12] 11. What are the advantages of liquid crystal display?[MAY-13} 12. What is meant by intrinsic absorption? 13. What is meant by electro-absorption? 14. What are high TC superconductors? { DEC-12] 15. What are the laser light properties? 16. What is meant by laser action? 17. What is meant by threshold condition for laser oscillation? 18. What are the drawbacks of homojunction laser diodes? 19. Define internal quantum efficiency of a laser or LED? 20. What are the factors that decrease the life time of laser diode? 21. Mention some application of Electro luminescence. 22. What is meant by mode locking laser? 23. Define Electroluminescence. 24. Why cathode luminescence is less efficiency than photoluminescence 25. Find the Q-factor of a laser cavity oscillating at 650 nm and having a line width of 1 MHZ

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PART -B Explain Emission, Absorption, and Radiation of Laser. Explain the construction and working of various Display devices. Explain the following terms (i).Photo luminescence (ii).Cathode luminescence (iii).Electro luminescence (iv).Injection luminescence Write short notes on Mode locking of semiconductor laser Explain in detail the application of laser Discuss about the various Classification of laser Explain the operation of LED and derive an expression for the frequency response and bandwidth of an LED. What are the major advantages of LED over LCD? { MAY-12]

EC6016 OPTO ELECTRONIC DEVICES 9. Derive expressions for gain in a level laser medium? {DEC-12] 10. Explain the basic principle of LED? { JUNE-12] 11. Explain the transient response of LEDS? 12. Discuss the different types of hetero-S structure LEDs along with diagrams? DEC13 13. Define Responsivity of an LED and Calculate the Responsivity of an LED with ηo=3% λ=1µm.(4 marks) 14. Determine the number of modes of an GaAs laser supported by the Gain spectrum which has a bandwidth of 6nm.the Laser has a cavity length of 200µm and the peak emission wavelength is 800nm.(6marks) 15. Describe the operation of Semiconductor lasers. 16. Draw the common – cathode LED seven segment display and explain its working.

UNIT-III OPTICAL DETECTION DEVICES

PART-A

1.Define intrinsic photo conductor and extrinsic photo conductor. 2.Define Quantum efficiency of a photo conductor. 3.What is Johnson (or) thermal noise? 4.What is the gain of DC photo conductor? 5.Define directivity of a photo diode. 6.What is impact ionization? 7.What is a photodiode? 8.What are the properties of photodiodes? { MAY-12] 9.What is meant by binary digital modulation? 10. State franz –keldysh effect. 11. State stark effect. 12. What are the different factors that determine the response time of photo detector? { MAY-12] 13. What are the condition for total internal reflection. 14. What are the different noises present in the avalanche photodiode? { MAY-12] 15. What are the required properties of photo detector? 16. Draw the VI characteristics of Photo Diode. 17. A short noise limited detector is to operate at 2 GHZ.Calculate the Current level required to ensure an SNR of 200

PART-B 1. Explain the basic principle of electro-optic modulators? {JUNE-12] 2. Describe the electro-optic amplitude modulation with neat sketch? {MAY-13] 3. Explain the quantum confined stark effect (QCSE)?

EC6016 OPTO ELECTRONIC DEVICES 4. 5. 6. 7.

Explain the self-electro-optic device? Discuss the different types of noises in the photodiodes {NOV/DEC-12] Give an account on the high speed and long wavelength photodiodes? {MAY-13,10,12] Derive expressions for the gain of a photoconductor with dc excitation at different levels of increasing applied bias? {MAY-10,08,07] 8. Discuss the characteristic of P-I-N photodiode with energy band diagram?

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Compare the noise performance of Photoconductor and PIN photodiode Discuss in detail about the construction and working of PIN photodiode. Write a note on Hetero junction diode. Write a note on .avalanche photodiode Derive the expression for the gain –bandwidth product of a photoconductor with dc excitation at different levels of increasing applied bias if the device has one ohmic contact and the other rectifying or Blocking. (16) 14. Describe the energy band diagram of a N-P+-N hetro junction modulated barrier photodiode under biased condition and arrive at the expression for Responsivity. (16 Marks) 15. Explain the structure and operation of thermal Detector. (8marks) 16. Explain the various detector performance parameters. (8marks) 17. Consider a typical avalanche photodiode with the following parameters incident Optical power=50mw Efficiency =85%, optical Frequency=4.5*10 14HZ, Breakdown voltage =30 v Dark current =12.5na parameter n for the multiplication =2.Assume that the series resistance is negligible. Calculate the photon current UNIT-IV OPTOELECTRONIC MODULATOR PART-A (2Mark Questions) 1. What are the advantages of optical fiber communication system? 2. Define birefringence 3. What is Electro-Optic effect? 4. Define Pockets effect and Kerr effect. 5. Why? Junction carrier –Injection modulators are called as BRAQWET modulator. 6. List the characteristics of Self-Electro-Optic Effect (SEED) Devices. 7. Compare analog and digital Modulation. 8. Name the Different types of electro-optic modulators. 9. What are the drawbacks of analog modulation? 10. What are magneto –optic devices? 11. What are Acoustopic devices? 12. What is need of SEED Device? 13. Mention any four Electro optic devices PART-B

1.Differentiate Analog and Digital modulation techniques (8) 2. What is Electro-Optic Effect? and explain how this is suitable for electro-optic phase modulation and electro-optic amplitude modulation(16)

EC6016 OPTO ELECTRONIC DEVICES 3. Explain Quadratic Electro-Optic effect with suitable diagram (16) 4. Explain the operation of Self Electro-Optic device with necessary diagram (08) 5. Write a short note on Bipolar controller Modulator(8) 6. Write a short note on Programmable memory devices(8) 7. Write short notes on the following(i).Tunable threshold logic gates (ii).Optical crossbar switching(8+8) 8. Discuss in detail the Operation of Electro-Optic Amplitude modulation with necessary diagram(16) 9. Write short notes on i) Self Electro- optic Device ii) Tunable Threshold Logic Gate 10. Discuss in Detail the principle of operation of a photonic switch based on self electro optic device(SEED) (10) 11. Explain the concept of Bipolar Controller modulator. 12. Explain in the concept of Birefringence in uniaxial crystal with necessary diagram (8 marks) 13. Derive the expression for retardation between two waves due applied voltage in electro optic material. 14. Discuss in detail the principle and operation of QCSE based optical. UNIT V OPTO-ELECTRONIC INTEGRATED CIRCUITS PART-A (2Mark Questions) 1. What is opto-electronic integration? 2. What are the challenges met by opto-electronic integrated circuit? 3. Define receiver sensitivity of photo receiver. 4. What are the three types of integration used in photo receiver? 5. Write the expression for power dissipation of a Laser. 6. Explain how guided waves can be formed? 7. Differentiate Hybrid and Monolithic integration. 8. Mention the applications of optoelectronic integrated circuits. 9. Define waveguide 10. Explain Briefly about Directional Coupler 11. List out the advantages of opto-electronic integrated circuit? 12. Explain Kerr and Pockels Effect. 13. What are optical wave guides? 14. List the application of opto- Electronic integrated circuits. 15. What is meant by plasma etching PART-B 1.What is the need for integration of opto-electronic devices (8 marks) 2.Explain briefly the application of opto-electronic integrated circuits (OEIC) (8 marks) 3.With neat diagram, Explain the performance of Front end photo receivers (16 marks) 4.Explain the noise and bandwidth considerations of photo receiver. (16 marks)

EC6016 OPTO ELECTRONIC DEVICES 5.Explain the various steps involved in the fabrication of OEIC transmitter and also draw the equivalent circuit of integrated transmitter.(16 marks) 6.Explain in detail about the properties of .optical guided wave and couplers. (16 marks) 7.Distinguish between hybrid and monolithic integration. (4 marks) 8.Describe in Detail about monolithically integrated front end Photo diode receiver. Also explain with neat sketches the measurement of the eye diagram. (12 marks) 9. Describe with schematic of Guided wave Mach-Zehnder interferometer and hence arrive at the expression for half wave voltage Vπ

(16 marks)

10.

Discuss the noise performance in integrated photo Receivers.

11.

Describe the working of integrated transmitters and Receivers.

12.

Explain the merits and limitations of monolithic integration.

13.

What is molecular Beam Epitaxy? Explain