Measuring fiber connection loss using steady-state power distribution: a method.

This paper describes conditions for the reproducible measurement of optical fiber connection losses. The steady-state power distribution is characterized by the width of the far-field pattern (FFP). A method is proposed to determine the power distribution in the fiber from the measured FFP. Using this method, connection losses of graded-index fibers are calculated for various widths of the FFP. Calculated results are verified experimentally. The width of the FFP must be controlled to within an accuracy of 3% for a 0.05-dB reproducibility of the connection loss. Connection loss dependence on mismatch of fiber parameters is also calculated. Calculation shows that variations in core radius, numerical aperture, and index gradient have to be controlled to within 3%, 6%, and 0.3, respectively, for the same reproducibility.