Page 1 :
Question Bank of Engg. PHYSICS_KAS -101T/201T, Unit-V(Fiber Optics & Laser), , , , SHORT ANSWER TYPE QUESTIONS:, Low Difficulty level Questions, , What is acceptance angle?, , What do you mean by dispersion?, , What is stimulated emission of radiation ?, , What are the main components of an optical fiber ?, , What do you understand by population inversion in a laser system?, , VPYnNE, , Average Difficulty level Questions, , 6. Explain the propagation mechanism and optical communication in optical fibre. Also discuss about the, signal loss in optical fibres., , 7. Describe scattering loss in optical fiber., , , , High Difficulty level Questions, , 8. Explain the basic principle of optical fibre. Discuss fibre classification on the basis of refractive index, profile. What are the advantage of optical fibre over copper wire., , 9. What do you mean about acceptance angle and cone in a fiber?, , 10. What is the concept of four level laser system?, , , , LONG ANSWER TYPE QUESTIONS:, Low Difficulty level Questions, , Derive an expression for it acceptance angle., , What is an optical fiber ? Discuss its classification., , Derive an expression for dispersion., , Draw the constructional and energy level diagram of Ruby laser. Why He-Ne laser is superior than, Ruby Laser., , , , Peper, , w, , Discuss the He-Ne Laser with necessary diagrams. Give it superiority over Ruby Laser., 6. A He-Ne laser emit a light of wavelength 6328A at 300K. Calculate the ratio of population of the two, state., , Average Difficulty level Questions, 7. Explain the propagation mechanism and optical communication in optical fibre. Also discuss about the, , signal loss in optical fibres., 8. What are the important features of stimulated emission ? Obtain a relation between transition probabilities of, , , , spontaneous and stimulated emi, , 9. The Ruby laser has two states at 27°C, if it emits light of wavelength 7000A then calculate population, ratio. Boltzmann constant K= 1.38x 10°/K, h=6.626x 10™ Js., , 10. In a Ruby laser total number of Cr“? ions is 2.8 x 10'°. If the laser emits radiation of wavelength 7000A., Calculate the energy and momentum of laser pulse., , 11. The optical power after propagating through a 500m long fiber, is reduced to 35% of its original value., Calculate fiber loss in dB/km., , 12. A communication system uses a 10km fibre having a loss of 2.5 dB/km. Compute output power if the, input power is 500pW., , ns