Leaky modes on W-fibers: mode structure and attenuation.

The mode structure of a W-fiber has been discussed in conjunction with that of an SC-fiber using the WKB approximation, and the leaky mode attenuation coefficient has been derived using Poynting's vector theorem. Furthermore, a simplified expression for the attenuation coefficient of the W-fiber has been obtained and compared with that of the SC-fiber. Comparisons between the calculated and measured spatial transient responses have also been carried out and shown to agree well with each other. The results are useful in the study of W-fiber properties.