Comments on "Radiation from Curved Dielectric Slabs and Fibers" [Letters]

In the above paper, Lewin gave an expression for the bending loss of a dielectric fiber with circular cross section. I have shown that the bending loss of arbitrary optical guides can be obtained in a simple manner when the field of the straight guide is known. The purpose of this letter is to show that the results of the two theories are in agreement, except for a factor of 2.