Dispersion in optical fiber

What is dispersion in optical fiber communication?

• Compression of light pulses

• Broadening of transmitted light pulses along the channel

• Overlapping of light pulses on compression

• Absorption of light pulses

For no overlapping of light pulses down on an optical fiber link, the digital bit rate BT must be:

• Less than the reciprocal of broadened pulse duration

• More than the reciprocal of broadened pulse duration

• Same as that of than the reciprocal of broadened pulse duration

• Negligible

The maximum bit rate that may be obtained on an optical fiber link is 1/3Γ. State whether the given statement is true or false.

• True

• False

3dB optical bandwidth is always ___________ the 3dB electrical bandwidth.

• Smaller than

• Larger than

• Negligible than

• Equal to

What is pulse dispersion per unit length if for a graded index fiber, 0.1μs pulse broadening is seen over a distance of 13 km?

• 6.12ns/km

• 7.69ns/km

• 10.29ns/km

• 8.23ns/km

A multimode graded index fiber exhibits a total pulse broadening of 0.15μsover a distance of 16 km. Estimate the maximum possible bandwidth, assuming no intersymbol interference.

• 4.6 MHz

• 3.9 MHz

• 3.3 MHz

• 4.2 MHz

Chromatic dispersion is also called as intermodal dispersion. State whether the given statement true or false.

• True

• False

The optical source used in a fiber is an injection laser with a relative spectral width σ_λ/λ of 0.0011 at a wavelength of 0.70μm. Estimate the RMS spectral width.

• 1.2 nm

• 1.3 nm

• 0.77 nm

• 0.98 nm

In waveguide dispersion, refractive index is independent of

• Bit rate

• Index difference

• Velocity of medium

• Wavelength

Intermodal dispersion occurring in a large amount in multimode step index fiber results in

• Propagation of the fiber

• Propagating through the fiber

• Pulse broadening at output

• Attenuation of waves