Loss factors analysis for single-mode fiber splicing without care axis alignment

Splice loss factors of single-mode fiber splicing lacking core axis alignment were analyzed quantitatively. The optimum splice conditions were also investigated in detail. It was seen that the dominant splice signal-loss factors are core deformation caused by fiber axis discrepancy and core axis misalignment caused by core eccentricity. To suppress average splice loss to less than 0.1 dB, average core eccentricity suppression to less than 0.35 μm is necessary. A novel method for setting fiber endface gaps accurately and quickly is proposed that helps to realize the optimum condition. This method is based on fiber endface image detection using photodiodes, and it has a quick setting time of 5 s and a high accuracy with a setting error of 0.5 μm. A fusion splice machine manufactured based on the present endface setting method was developed and evaluated. As a result, an average splice loss of 0.012 dB was successfully achieved