W fiber design considerations.

The baseband frequency characteristics and the average confinement of light to core properties of a W fiber are analyzed in conjunction with corresponding singly clad (SC) fibers under some ideal assumptions It is found that the bandwidth of a W fiber is almost equal to that of the SC fiber that has no intermediate layer and is much wider than that of the other SC fiber in which the intermediate layer extends to infinity. The average fractional power flow outside the core in a W fiber is drastically reduced in comparison with both SC fibers. Practical design considerations are deduced from a typical example.