Poor Fiber Cleave: Angled or chipped cleaves prevent proper core alignment. Misalignment: Incorrect positioning of fibers leads to light leakage. Core vs Cladding Mismatch: Using different fiber types without adjustment. Fiber optic pigtails are used to connect fiber optic cables using fusion or mechanical splicing. What is a mechanical splice? What is a fusion splice? Why splice? Fiber splicing is one way to join two optical fibers together so the light energy from one optical fiber can be transferred to another. 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. 1 dB) than for mechanical splices (around 0. This tool uses the Marcuse Gaussian Approximation to calculate losses from intrinsic mismatch and extrinsic alignment errors. The focus of this paper is ultra low loss splicing for telecommunications product assembly, with typical loss of <0.