Question

Q1)in maltimode step index fiber,the pulsebroadening due to intermodel dispersion increase linearly with the fiber length (true and why this statement is true or false and prove why false) .

Q2)APD is preferable in shot noise limited case whereas PIN is preferable in thermal noise limited case(true and why this statement is true or false and prove why false).

Q3)multimode GI-Fiber are characterized by higher gathering capability and lower intermodal dispersion compared to multimode step index fiber(true and why this statement is true or false and prove why false)

Q4)OTDR is the suitable choice for measuring the attenuation coefficient of the fiber as well as for monitoring the status of the optical fiber link(true and why this statement is true or false and prove why false).

Q5) Optical isolator device is transparent to the optical beam in one direction(true and why this statement is true or false and prove why false). atement is true or false and prove why false).

Answer 1

1) false

The overall dispersion in multimode fibers comprises both chromatic and intermodal terms. The total RMS pulse broadening σ_T is given by

Where σm = RMS pulse broadening due to material dispersion
σ_i= RMS pulse broadening due to intermodal dispersion.

2) True

APD sensitivities are batter then PIN sensitivities.