Angular misalignment loss

Angular misalignment loss: Power loss caused by the deviation from optimum angular alignment of the axes of source to waveguide, waveguide to waveguide, or waveguide to detector.

Note 1: The waveguide may be dielectric (an optical fiber) or metallic.

Note 2: Angular misalignment loss does not include lateral offset loss[?] and longitudinal offset loss.

Source: from Federal Standard 1037C