B.TECH - Semester 7 optical communications Question Paper 2020 (sep)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- List the advantages of optical fiber communication.
- What are two types of rays that can propagate through optical fiber?
- What is photonic crystal fiber?
- List the requirements of optical communication source.
- Define and explain the quantum efficiency of photo detector.
- List various noise sources encountered in photo detectors.
- What are the advantages of APD?
- What are the applications of the optical amplifiers?
- What is WDM?
- Draw the block diagram of VLC system. $$ \text { ( } 10 \times 2=20 \text { Marks) } $$ Answer one full questions from each module. Each question carries 20 marks.
- (a) Explain the different scattering and absorption losses in fibres. $\mathbf{1 5}$
- (b) An optical signal at a specific wave length has lost $55 \%$ of its power, after traversing 7 km of fiber. What is the attenuation in dB/km of this fiber? 5 OR
- (a) Describe the different types of speciality fibers and specify the applications of each one them. Explain polarization mode dispersion. 15
- (b) A silica glass fiber has a core refractive index of 1.5 and the cladding refractive index of 1.45 . Calculate the critical angle for the core cladding interface.
- (a) Outline the common LED structure for optical communication. Compare LED and laserdiode.
- (b) An APD with a multiplication factor of 20 operates at a wavelength of 1500 nm . Calculate the quantum efficiency and the output current from the device if its responsivity is $0.6 \mathrm{~A} / \mathrm{W}$ and the total multiplied current is 318 ...
- (a) With diagram explain the principles of operation of an APD. Compare it with PIN diode.
- (b) The radiative and non radiative recombination lifetime of the minority carriers in the active region of the LED are 60 ns and 100 ns respectively. Determine the total carrier recombination. 15．（a）With a block diagram explain the working of an op...