Grating compensation of third-order fiber dispersion

Subpicosecond optical pulses propagating in single-mode fibers are severely distorted by third-order dispersion even at the fiber's zero-dispersion wavelength ( lambda /sub 0/). Using cross-correlation techniques, the authors measured the broadening of a 100-fs pulse to more than 5 ps after passing through 400 m of fiber near lambda /sub 0/. The measured asymmetric and oscillatory pulse shape is in agreement with calculations. A grating and telescope apparatus was configured to simultaneously equalize both third- and second-order dispersion for wavelengths slightly longer than lambda /sub 0/. Nearly complete compensation has been demonstrated for fiber lengths of 400 m and 3 km of dispersion-shifted fiber at wavelengths of 1560-1580 nm. For the longer fibers, fourth-order dispersion due to the grating becomes important.<
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