Rare earth doped amplifying optical fiber for compact devices and method of manufacturing thereof

摘要

This rare earth doped amplifying optical fiber comprises, from the center to the periphery: an inner core, an inner cladding, a depressed trench and an outer cladding. The inner core has a radius r 1 between 2.5 µm and 3.1 µm, a refractive index difference ”n 1 between 8.0×10 -3 and 10.5×10 -3 with respect to the outer cladding and has a silica-based main matrix doped with at least one rare earth element. The inner cladding has a radius r 2 between 4.1 µm and 15.8 µm. The depressed trench has a radius r 3 and a negative refractive index difference ”n 3 between -14.2x 10 -3 and -3.7×10 -3 with respect to the outer cladding. r 2 -r 1 is comprised between 1.4 µm and 12.9 µm, r 3 -r 2 is comprised between 4.7 µm and 18.9 µm; and the volume integral of the depressed trench, V 13 , defined as V 13 = 2. ˆ« r 2 r 3 ”n r . rdr ‰ˆ r 3 2 - r 2 2 × ” �¢ n 3 , is comprised between -2200x 10 -3 µm 2 and -1600x 10 -3 µm 2 . Use in compact devices.