Consider the following advantages of optical fiber-cables:
1. Small diameter
2. Immunity to cross talk and electromagnetic interference
3. Laser and LED modulation methods lend themselves ideally to digital operation.
Which of these advantages are correct?

The fibers which relax the spectral requirements for optical sources and allow flexible wavelength division multiplying are known as . . . . . . . .

A. Dispersion-flattened single mode fiber

B. Dispersion-enhanced single mode fiber

C. Dispersion-compressed single mode fiber

D. Dispersion-standardized single mode fiber

Photonic crystal fibers also called as . . . . . . . .

A. Conventional fibers

B. Dotted fibers

C. Stripped fibers

D. Holey fibers

An optical fiber behaves as a birefringence medium due to differences in . . . . . . . .

A. Effective R-I and core geometry

B. Core-cladding symmetry

C. Transmission/propagation time of waves

D. Refractive indices of glass and silica

Any amount of stress occurring at the core-cladding interface would be reduced by grading the material composition.

A. True

B. False