Open AccessEffect of frequency chirp on supercontinuum generation in photonic crystal fibers with two zero-dispersion wavelengths
Author(s) -
Hua Zhang,
Song Yu,
Jie Zhang,
Wanyi Gu
Publication year - 2007
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.15.001147
Subject(s) - supercontinuum , chirp , optics , dispersion (optics) , wavelength , chirp spread spectrum , zero dispersion wavelength , materials science , photonic crystal fiber , self phase modulation , physics , nonlinear optics , optical fiber , dispersion shifted fiber , laser , telecommunications , channel (broadcasting) , spread spectrum , fiber optic sensor , computer science , direct sequence spread spectrum
The effect of initial frequency chirp is investigated numerically to obtain efficient supercontinuum radiation in photonic crystal fibers (PCFs) with two closely spaced zero-dispersion wavelengths. The positive chirps, instead of zero or negative chirps, are recommended because self phase modulation and four-wave mixing can be facilitated by employing positive chirps. In contrast with the complicated and irregular spectrum generated by negative-chirped pulse, the spectrums generated by positive-chirped pulses are wider and much more regular. Moreover, the saturated length of the PCF, corresponding to the maximal spectrum width, can be shortened greatly and the efficiency of frequency conversion is also improved because of initial positive chirps. Nearly all the energy between the zero-dispersion wavelengths can be transferred to the normal dispersion region from the region within the two zero-dispersion wavelengths provided that the initial positive chirp is large enough.