When λ is the optical wavelength in vacuum, k is given by $$k = \frac{{2\pi }}{\lambda }.$$  What does k stand for in the

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