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InsemMar 20242019 patternBE E&TC

Fiber Optic Communication (FOC) SPPU Insem Question Paper Mar 2024

All 4 questions from this SPPU insem paper, as printed. Read them here or open the PDF.

Open the PDFMost repeated FOC questions
Subject code
404190
Pattern
2019 pattern
Exam
Insem
Session
Mar 2024
Max. marks
30
Time
1 Hour
Semester
VIII
Paper code
[6270]-80

Printed for: B.E. (Electronics & Telecommunication Engineering) (Insem)

Instructions to the candidates

  1. Answer Q.1 or Q.2, Q.3 or Q.4 from following questions.
  2. Neat diagrams must be drawn wherever necessary.
  3. Figures to the right indicate full marks.
  4. Assume suitable data, if necessary.

Questions

  1. Q1

    1. a)

      A step index fiber has a relative refractive index difference of 1.3% & a core refractive index of 1.5. The core diameter is 100 μ m and operating wavelength is 850nm. Assuming fiber is kept in air, calculate numerical aperture of fiber, acceptance angle and critical angle.

      Also asked:Mar 2025

      [6]
    2. b)

      Compare single mode and multimode fibers.

      [4]
    3. c)

      Draw and explain optical fiber communication system showing all the key elements. Enlist the advantages of optical fibers as a communication media.

      Also asked:Mar 2025

      [5]

  2. Q2

    1. a)

      Explain intramodal dispersion, intermodal dispersion and overall fiber dispersion in optical fibers.

      [4]
    2. b)

      A multimode graded index fiber exhibits total pulse broadening of 0.1 μ sec over a distance of 15km. Calculate. i) Maximum possible bandwidth on the link ii) The pulse dispersion per unit length iii) The bandwidth-length product for the fiber

      Also asked:Mar 2025

      [6]
    3. c)

      Describe the following losses in optical fiber. i) Absorption ii) Attenuation iii) Scattering 2

      [5]

  3. Q3

    1. a)

      Explain the following terms for semiconductor laser diodes with neat diagram i) Absorption ii) Spontaneous Emission iii) Stimulate Emission

      [5]
    2. b)

      Explain working and characteristics of LED with diagrams. State its ad- vantages and disadvantages.

      [4]
    3. c)

      A double heterojunction InGAsP LED emitting at a peak wavelength of 1310 nm has radiative and non-radiative recombination times of 30ns and 100 ns respectively. The drive current is 40 mA Determine i) Bulk recombination lifetime ii) The internal quantum efficiency iii) Internal power level

      Also asked:Mar 2025

      [6]

  4. Q4

    1. a)

      Explain external quantum efficiency and the external power generated in the LED with necessary equations.

      [6]
    2. b)

      Distinguish direct and Indirect band-gap semiconductor materials. Also state the major requirements of good optical sources.

      Also asked:Mar 2025

      [6]
    3. c)

      Calculate the emission wavelength in nm of the light emitted using a semiconductor material with energy band-gap of 3eV 

      Also asked:Mar 2025

      [3]