Cladding mode resonances in short- and long-fiber grating filters: comment

Abstract

To obtain the coupling constant for core-mode-cladding-mode coupling, it is necessary to calculate the total power carried by the cladding mode, and the related formulas are given by T. Erdogan [J. Opt. Soc. Am. A14, 1773 (1997)] and [J. Opt. Soc. Am. A17, 2113 (2000)]. I found that my formulas for P1 and P3 are the same as Eqs. (B2) and (B16) in the 1997 paper, but Eqs. (B3)-(B15) for P2 are worth commenting on, and this comment gives our derivations.