B.TECH - Semester 7 optical communication Question Paper 2019 (jun)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- Explain intermodal and intramodal dispersionin optical fibers.
- Calculate the numerical aperture of a step index fiber having $n 1=1.48$ and $\mathrm{n} 2=1.46$. What is the maximum entrance angle $\theta_{0 \text { max }}$ for this fiber if the outer medium is air.
- How do hetero-junction structures improve optical and carrier confinement?
- Can an optical fiber act as both monomode and multimode ? why?
- Calculate the quantum efficiency and responsivity of a photo detector if the number of incident photons are 800 and the corresponding electron generation in photodiode is 500 per sec at a wavelength of 1300 nm .
- Explain the operation of PIN diode and compare it with APD.
- Show that three exists an optimum value for soliton pulse width for minimum ⋅ BER.
- What is the need of optical amplifiers ? Briefly explain the different types.
- List the merits of soliton communication systems.
- Explain the principle of AWG PART - B Answer any two questions from each Module.
- Describe the mechanism of intermodal dispersion in a multimode step index fiber. Show that the total broadening of a light pulse $\wedge T_{s}$ due to intermodal dispersion in a multimode step index fiber may be given as $\Delta T_{s}=L(N A)^{2} / 2 ...
- Explain the vapour phase oxidation process of fiber fabrication with suitable figures.
- (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 the laser. $$ (2 \times 10=20 \text { Marks }) $$
- Briefly discuss the possible sources of noise in optical fiber receivers. Derive an expression for the Bit Error Rate in optical receivers.
- Explain the working principle of EDFA with suitable diagram and derive an expression for the gain of of EDFA.
- (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.
- Explain the architecture of WDM system with block schematics and discuss the challenges in DWDM.
- How bit error rate of a soliton link is effected when repeater spacing is increased, Bit rate is increased, Transmission distance is increased.
- Explain Briefly Light wave networks, soliton-soliton interactions and wavelength tuneable sources. ( $2 \times 10=20$ Marks)