Page "learned" Paragraph 1358

The packing efficiency, F.R., of fiber plates did not receive much attention in the literature, probably as it is high for the larger fibers generally used, until rather recently.

For circular fibers in a closely packed hexagonal array, the packing efficiency is given by: Af where Af, and 0.906 is the ratio of the area of a circle to that of the circumscribed hexagon.

For the small diameter fibers now technically feasible and required for about 100 Af resolution, Af.

The cladding thickness is about 0.5 M, hence, Af and Af.