GRATING COMPENSATION OF 3RD-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 (lambda0). Using cross-correlation techniques, we measured the broadening of a 100 fs pulse to more than 5 ps after passing through 400 m of fiber near lambda0. 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 lambda0. We demonstrated nearly complete compensation 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.