An optical waveguide, such as an optical fiber, including a core having a refractive
index nco and a radius rco; an inner cladding laterally surrounding
the core, the inner cladding having a refractive index nic and an outer
radius of ric; an outer cladding laterally surrounding the inner cladding,
the outer cladding having a refractive index noc; and a narrow depressed
well, wherein nconocnic. The range
of the ratio of the inner, depressed-well clad radius, ric, to core
radius, rco, varies from about 2.4 to 3.0. The waveguide has a +
of about 0.0014 to 0.0021, a - of about -0.0021 to -0.0034, and a Tot
of about 0.0043 to 0.0049.
