Single mode optical fiber

摘要

A single mode optical fiber comprises from center to periphery:
- a core having a radius (a) and an index difference (Dn 1 ) with outer cladding (Dn cl ) comprised between -0.5.10 -3 and 0.5.10 -3 ;
- an inner depressed cladding having a radius (r ring1 ) and an index difference (Dn inner ) with outer cladding ;
- a ring having an inner radius (r ring1 ) comprised between 21µm and 35µm, an outer radius (r ring2 ) and an index difference (Dn ring ) with the outer cladding comprised between -0.5.10 -3 and 0.5.10 -3 ;
- an outer depressed cladding having a radius (r out ) and an index difference (Dn out ) with outer cladding. The fiber has a ratio of the volume of the core over the width of the ring (W ring ) comprised between 0.12µm and 0.2µm and the outer depressed cladding has a volume comprised between 15 µm 2 and 30 µm 2 . A low cost preform with increased capacity can be obtained.