The acceptable splice loss is dependent on the power budget of the transmission system and it is the responsibility of the system owner to define acceptable splicing performance for the marine service provider.
The UJC, through its fiber splice qualification process, specifies optimized splicing parameters for the UJC recommended fusion splicing equipment which minimize the splice loss and maintain fiber splice reliability. Both are consistent with industry practice for the fibers being spliced and their relative MFD. e.g. SMF to SMF, or DSF to NDSF