B.TECH - Semester 7 optical communication Question Paper 2013 (dec)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- Draw the structure of optical fiber and explain the light guiding mechanism through it.
- What is the cause of GVD in single mode fibers?
- Briefly explain Photonic crystal fibers.
- Differentiate spontaneous emission with stimulated emission.
- Explain the working of APD.
- What are the different noise components present in a photo receiver?
- What are the different modulation schemes used for coherent communication?
- What is transparent condition of an amplifier?
- What is the need of periodic amplification in soliton communication systems?
- Explain the working of a circulator with figure. $$ \text { ( } 10 \times 2=20 \text { Marks) } $$ P.T.O. Answer one full questions from each Module. Each question carries 20 marks.
- (a) Draw the attenuation characteristics of a optical fiber and describe the various losses in optical fibers.
- (b) An optical signal at a specific wavelength has lost $50 \%$ of its power after traversing 3 Km of fiber. What is the attenuation in $\mathrm{dB} / \mathrm{km}$ of this fiber?
- (c) Explain the different types of dispersion with suitable equations.
- (a) Explain the vapour phase oxidation process of fiber fabrication with suitable figures.
- (b) Explain (i) hollow core fiber (ii) photonic bandgapfiber
- (a) Explain the lasing action in FP laser.
- (b) The threshold current of a semiconductor laser doubles when the operating temperature is increased by $50^{\circ} \mathrm{C}$, What is the characteristic temperature of 3 the laser.
- (c) Explain the operation of a PIN photo diode.
- (a) Calculate the quantum efficiency and responsivity of a photo detector if the number of incident photons are 1000 and the corresponding electron generation in photodiode is 750 per sec at a wavelength of 1300 nm . 5
- (b) Explain the working of APD.
- (c) What are the noises in detectors?
- (a) Describe the working of an OTDR with a block diagram.
- (b) Explain the working principle of EDFA with suitable energy band diagrams. 10
- (a) Show that the received signal strength can be enhanced locally in coherent systems.
- (b) With a block schematic explain the working of ASK heterodyne system.
- (a) Explain the architecture of WDM system with block schematics and discuss the challenges in DWDM.
- (b) How bit error rate of a soliton link is effected when repeater spacing is increased. Bit rate is increased, Transmission distance is increased.
- (a) Illustrate four wave length multiplexing system using MZ interferometer.
- (b) Explain the principle of Tunable filters.
- (c) Write notes on
- (i) Free space optics (ii) LiFi technology