Causes include poor fusion splicing, misalignment of fiber cores, excessive cleave angle, or contamination in the splice. Re-splice the fiber if necessary and ensure proper alignment and cleanliness before fusing. If the NA of the transmitting fiber is larger than the NA of the receiving optical fiber, a loss may occur. IEC 61300 standards and best practices from. If your fusion splice is showing high splice loss, don't panic. When stripping and cleaving fiber, fine glass shards can be released that, if not properly cleaned up and disposed of, can lodge in the. Splice loss refers to the part of the optical power that is not transmitted through the splice and is radiated out of the fibre. You want low splice loss because signal loss can weaken communication and reliability.