Patent ID: 8483535

Claim:
A multimode optical fiber, comprising: a central core having a radius r 1 and an alpha-index profile with respect to an outer cladding; a first depressed trench positioned between said central core and said outer cladding, said first depressed trench having (i) a width w 2 , (ii) a refractive index difference Δn 2 with respect to said outer cladding, and (iii) a volume v 2 ; an inner cladding positioned between said first depressed trench and said outer cladding, said inner cladding having a width w 3 of less than about 4 microns and a refractive index difference Δn 3 with respect to said outer cladding; and a second depressed trench positioned between said inner cladding and said outer cladding, said second depressed trench having (i) a width w 4 , (ii) a refractive index difference Δn 4 with respect to said outer cladding, and (iii) a volume v 4 ; wherein said inner cladding's refractive index difference Δn 3 is (i) greater than said first depressed trench's refractive index difference Δn 2 and (ii) greater than said second depressed cladding's refractive index difference Δn 4 ; and wherein said second depressed trench's volume v 4 is greater than said first depressed trench's volume v 2 .