Pulse dispersion in multimode fibers with graded B2O3-SiO2 cores and uniform B2O3-SiO2 cladding

Abstract

Dispersion differences between B₂O₃ and SiO₂ constituents make nonparabolic profiles optimal equalizers of modal group delays. Pulse dispersion measurements were correlated with graded refractive‐index profile shapes in a systematic study of a series of multimode fibers with graded B₂O₃‐SiO₂ cores and uniform B₂O₃‐SiO₂ cladding. One of the fibers had an α≈1.77 power law exponent, which at λ≈907.5 nm wavelength caused 2σ=0.26 nsec/km full rms output pulse spreading. When expected material dispersion effects were deconvolved from the output pulse spreading, the resultant pulse width was approximately 75 times less than the result expected for a comparable step‐index fiber.