Question 1: In a 100-ns pulse, 6 X 106 photons at a wavelength of 1300nm fall on an InGaAs photo detector. On an average 5.4 X 106 electron-hole pairs are produced. Determine the quantum efficiency.
Question 2: Photons of energy 1.53 X 10-19 J are incident on the photodiode that consists of responsivity of 0.65A/W. If the optical power level is 10uW, then determine the generated photocurrent. For the wavelength range 1300nm < ? < 1600nm, the quantum efficiency for InGaAs is around 90%. Determine the responsivity in this wavelength range.
Question 3: A given silicon Avalanche photodiode consists of a quantum efficiency of 65% at a wavelength of 900nm. Assume 0.5uW of optical power generates a multiplied photocurrent of 10uA. Determine multiplication factor M.
Question 4: If the photodiode capacitance is 3pF, the amplifier capacitance is 4pF; the load resistor is 1KO, the amplifier input resistance is 1MO, CT = 7pF and RT = 1KO, determine the circuit bandwidth.
Question 5: What do you mean by the term preamplifier? What are its different types? What are benefits and drawbacks of each kind of preamplifier?
Question 6: Describe and draw optical transmitter Circuit. Describe the signal gets modulated and launched in the optical fiber.
Question 7: What are the sources of noise in optical receiver? As well write S/N ratio for typical optical receiver.
Question 8: What are the parameters considered for designing an optical receiver? Describe their significance.
Question 9: What is different modulation methods used in optical communication System? Describe any one in detail.
Question 10: Write notes on:
a) Power budgeting
b) Mode theory
c) Optical transmitter circuit