The best method is to use a bare fiber adapter on the power meter to measure the output of the bare fiber, then attach the splice. Part one consists of OTDR trace data in the form of pigtail and bi-directional span shots. A final document containing splice locations and distances, averaged splice losses, and. Correct fiber optic pigtail splicing will bring lower loss and attenuation to the optical fiber system, and bring better performance. The effect of the backscatter level mismatch reverses the sign of the loss value reversing the measurement direction, allowing it to be. There are two reasons we may want to test bare fiber, by that we mean fiber that has not been terminated in connectors but is simply plain optical fiber, The first one is to ensure the fiber or cable being manufactured meets its specifications, as is done by every manufacturer.