B.TechSemester 52023-24Optical CommunicationKEC058
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Optical Communication (KEC058) - AKTU Question Paper 2023-24

B.Tech · Semester 5 · Free PDF Download

This is the official AKTU Optical Communication Previous Year Question Paper for B.Tech Semester 5, academic session 2023-24. Published by Dr. A.P.J. Abdul Kalam Technical University (AKTU/UPTU), Lucknow. Free PDF download — no login required.

Course:B.Tech
Semester:Semester 5
Session:2023-24
University:AKTU / UPTU

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Questions Asked in 2023-24

Optical Communication (KEC058) — complete question paper · 100 marks · 3 Hours

Section AAttempt all q u e s t i o n s i n b r i e f .
  • a
    Discuss Mode field diameter. 2 1
  • b
    Explore why the Refractive Index (R.I.) of core and cladding a re different. Which one has greater R.I. and why
  • c
    Illustrate stimulated Raman Scattering. 2 2
  • d
    Explain Kerr Effect used in an optical communication. 2 2
  • e
    Discuss the concept of population inversion in Optical Source. 2 3
  • f
    Differentiate surface emitti ng LED and edge emitting LED. 2 3
  • g
    Illustrate Source to Fiber Power Launching in optical communic ation. 2 4
  • h
    Illustrate the importance of multiplication factor in avalanch e photodiodes. 2 4 i. Explain Quantum Limit in optical communication. 2 5 j. Discuss receiver selectivity. 2 5
Section BAttempt any three o f t h e f o l l o w i n g :
  • a
    Explain Phase and Group Velocity with proper derivation. 1 0 1
  • b
    Illustrate the linear scatte ring losses in optical fibers with respect to
  • c
    Explain the requirement for optical sources to feed into fib er and optical modulation bandwidth. Enlist the advantage & Disadvantages of LASER & LED
  • d
    Explain p-n junction photodiode. A photodiode has a quantum efficiency of 65 % when the photons of energy 1.5 x 10 -19 J are incident upon it. Evaluate (i) the wavelength at which the photodiode is operating (ii) the incident optical pow er required to obtain a photocurrent of 2.5 µA
  • e
    Write a short note on the following terms
  • 1
    Multichannel & Multiplexing Transmission Techniques
  • 2
    Eye Diagram Pattern Features
Section CAttempt any one p a r t o f t h e f o l l o w i n g :
  • a
    A typical relative refractive index difference for an optica l fibre designed for long distance transmission is 1%. Estimate the NA and the solid acceptance angle in air for the fibre when the core index is 1.46. Further, compute the cri tical angle at the core– cladding interface within the fibre. It may be assumed that the concepts of geometric optics hold for the Fiber
  • b
    Summarize between step index and Graded index fiber. Compute the cutoff wavelength for a step index fibre to exhibit single-mode operation when th e core refractive index and radius are 1.46 and 4.5 mm, respectively, with the relative index difference being
  • a
    When the mean optical power launched into an 8 km length of fibre is 120 mW, the mean optical power at the fibre output is 3 mW. Calculate
  • a
    the overall signal attenuation or loss in decibels through the fibre assuming there are no connectors or splices
  • b
    the signal attenuation per kilometre for the fibre
  • c
    the overall signal attenuation for a 10 km optical link usi ng the same fibre with splices at 1 km intervals, each giving an attenuation of 1 db
  • d
    the numerical input/output power ratio in (c)
  • b
    Illustrate Intermodal dispersion in detail. Derive rms pulse broadening due to intermodal dispersion in a multimode step index fiber
  • a
    Explain the principle, construction and working of semicondu ctor injection laser. Also define total efficiency and external power efficiency of a semiconductor injection laser
  • b
    Explain heterojunction structure of LED. The radiative and n on-radiative recombination lifetime of the minority carriers in the active region of a double heterostructure LED are 60 ns and 100 ns respectively. Evaluate the bulk recombination or total carrier recombination lifetime and power generated internally in the de vice when the peak wavelength is 0.87 µm at a drive current of 40mA
  • a
    Explain the construction and working of APD photo diode. Als o explain the effect of temperature on gain of an avalanche photodiode
  • b
    Explain P-I-N photodiode in detail. Also explain factors whi ch limit the speed of a photodiode
  • a
    Explore Power Penalty in optical communication. Also Explain Different Types of Power Penalties. Explore Error Control Techniques in detail
  • b
    Explore basic concept of Free Space Optics (FSO) based Commu nication System in detail and Explain Heterodyne Detection used in optical communication in details

Question text is extracted from the official AKTU question paper PDF above. Hindi translations are omitted — every question is printed in English in the original paper. Last verified: 2026-08-23.

Repeated Questions — KEC058

Questions that appeared in more than one session, found by comparing 3 years of Optical Communication papers (2021-22, 2022-23, 2023-24)

2x

Multichannel & Multiplexing Transmission Techniques

Appeared in: 2022-23 · 2023-24

2x

Explore Power Penalty in optical communication. Also Explain Different Types of Power Penalties. Explore Error Control Techniques in detail

Appeared in: 2021-22 · 2023-24

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