Influence of the length of a fiber waveguide on the determination of its losses

The total light losses in fiber waveguides measured by breaking off short pieces can exceed considerably the steady-state losses. The excess depends on the length of the sample L and the wavelength of light λ, increasing on increase in λ and on reduction in L. The effect is attributed to additional losses experienced by the high-order modes and by the dependence of these losses on λ.