| 摘要 |
PURPOSE:To suppress the characteristic variation rate even in a temperature characteristic test under severe conditions by coating an untapered part with an adhesive at a specific position from a tapered part end. CONSTITUTION:At the untapered part 2 of an optical fiber coupler 1 formed by fusion splicing and drawing, parts which are tapered to decrease in fiber external diameter by >=5% are defined as tapered parts 3 and the positions where the parts begin to be tapered are defined as tapered part ends 4. At least two places from the tapered part ends 4 to fiber ends are coated with adhesives at a 0-8mm distance from the tapered part ends 4, i.e., at positions (t) to form reinforcing layers 5. This optical fiber 1 has <=1% branch degree variation even when the severe thermal shock test under a condition of -40 to 85 deg.C is conducted and variation in its loss becomes <=0.1dB. |
