An Optical Time-Domain Reflectometer (OTDR) is the industry-standard tool for splice loss testing. It works by sending a pulse of light down the fiber and analyzing the backscattered light to create a trace, or signature, of the entire link. Splices appear as distinct “loss events”. Fiber Optic Testing Testing is used to evaluate the performance of fiber optic components, cable plants and systems. As the components like fiber, connectors, splices, LED or laser sources, detectors and receivers are being developed, testing confirms their performance specifications and helps. Reviewing OTDR traces for construction acceptance is where projects either get documented properly or turn into a six-month dispute. The contractor submits test results. Two different methods exist for splicing fibers: Typical splice loss values (the measure of loss in optical power across the splice point) are usually lower for fusion splices (typically less than 0.