| 摘要 |
The invention relates to a multimode optical fiber comprising an optical core and an optical cladding surrounding the optical core, the optical core having a refractive graded- index profile, the optical cladding comprising: an inner layer surrounding said optical core, an intermediate layer, called "depressed trench", surrounding said inner layer, an outer layer surrounding said depressed trench and having a constant refractive index, said depressed trench having a width W and a negative refractive index difference &Dgr;nt with respect to the outer layer, and being designed so as to satisfy the following inequality: |0.585677 - 114.681 x S + 13.7287 x S 2 + 18.7343 x S x W - 4.61112 x S x &Dgr;n t.103 - 0.913789 x W x &Dgr;n t.103| +2 x W x &Dgr;n t.103 < -30 wherein: S is the width of the inner cladding, which is comprised between 0.6 μm and 1.6 μm; &Dgr;nt is comprised between -11.10-3 and -4.10-3; W x &Dgr;n t.103 is lower than -25 μm. |
