| 摘要 |
A multimode optical fiber is provides, which includes an optical core and an optical cladding surrounding the optical core. The optical core has a refractive graded-index profile. The optical cladding includes: an inner layer surrounding the optical core, an intermediate layer, called a “depressed trench”, surrounding the inner layer, and an outer layer surrounding the depressed trench and having a constant refractive index. The depressed trench has a width W and a negative refractive index difference &Dgr;nt with respect to the outer layer, and is designed so as to satisfy the following inequality: |0.585677−114.681×S+13.7287×S2+18.7343×S×W−4.61112×S×&Dgr;nt·103−0.913789×W×&Dgr;nt·103|+2×W×&Dgr;nt·103<−30 wherein: S is the width of the inner cladding, which is included between 0.6 μm and 1.6 μm; &Dgr;nt is included between −11.10−3 and −4.10−3; and W×&Dgr;nt·103 is lower than −25 μm. |
