| 摘要 |
An optical fiber with a large effective area includes a core layer and a cladding layer. The core layer comprises an inner core layer having a radius of 1-4 μm and a relative refractive index difference &Dgr;12 of −0.2%≧&Dgr;12<0% relative to the outer core layer, and an outer core layer having a radius of 4-7 μm and a relative refractive index difference &Dgr;2 of −0.15%-0.05%. &Dgr;12 remains unchanged or increases as the radius of the inner core layer increases. The cladding layer comprises an inner cladding layer cladding the core layer and having a radius of 7-20 μm and a relative refractive index difference &Dgr;3 of −0.5%˜−0.1%, a depressed cladding layer has a radius of 12-40 μm, and a relative refractive index difference &Dgr;4 of −1.0%˜−0.3%, and an outer cladding layer having a relative refractive index difference &Dgr;5 of −0.2%˜−0.4%. |
