Question 1: Explain the method of intermodal dispersion in multimode step index fiber.
Question 2: Explain the phenomenon of modal noise in optical fibers and propose how it might be avoided.
Question 3: Describe what is meant by:
a) Modal Birefringence
b) The beat length.
Question 4: Describe what is meant by the critical bending radius for an optical fiber.
Question 5: What do you mean by Dispersion phenomenon? Describe in brief the different types of dispersion occurring in the optical fibers.
Question 6: What is dispersion shifted and dispersion flattened fibers.
Question 7: Two step index fibers exhibit the given parameters:
a) A multimode fiber with core refractive index of 1.5, a relative refractive index difference of 3% and an operating wavelength of 0.82um.
b) An 8um core diameter single mode fiber with a core refractive index similar as (a), a relative refractive index difference of 0.3% and an operating wavelength of 1.55um. Find out the critical bending radius of curvature at which large bending losses take place in both cases.
Question 8: A multimode graded index fiber exhibits total pulse broadening of 0.1us over a distance of 15 Km. Estimate:
a) Maximum possible bandwidth on the link supposing no inter symbol interference;
b) The pulse dispersion per unit length.
c) Bandwidth-length product for the fiber.
Question 9: Two polarization maintaining fibers operating at a wavelength of 1.3um encompass beat lengths of 0.7mm and 80m. Find out the modal birefringence in each case and comment on the outcomes.
Question 10: The difference between the propagation constants for the two orthogonal modes in a single mode fiber is 250. It is illuminated with light of peak wavelength 1.55um from an injection laser source with a spectral line width of 0.8nm. Find the coherence length in the fiber.