| 摘要 |
<P>PROBLEM TO BE SOLVED: To adapt the dimension and position of a depressed trench in a refractive index profile of an optical fiber in order to prevent adverse influences of a leaky mode specific for the concept using the trench. <P>SOLUTION: A multimode 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<SB POS="POST">1</SB>from 22 μm to 28 μm and a graded-index profile with a relative refractive index of 0.8% or more. The inner cladding has a radius r<SB POS="POST">2</SB>and a refractive index difference Δn<SB POS="POST">2</SB>with respect to the outer cladding. The depressed trench has a radius r<SB POS="POST">3</SB>and a negative refractive index difference Δn<SB POS="POST">3</SB>with respect to the outer cladding and surrounds the inner cladding. In the multimode optical fiber, 0.0115807+0.0127543×(r<SB POS="POST">2</SB>-r<SB POS="POST">1</SB>)+0.00241674×1000Δn<SB POS="POST">3</SB>-0.00124086×(r<SB POS="POST">3</SB>-r<SB POS="POST">2</SB>)×1000Δn<SB POS="POST">3</SB><2% and the width×depth of the depressed trench is less than -20 μm. <P>COPYRIGHT: (C)2013,JPO&INPIT |
