| 研究概要 |
The effect of third-order dispersion on the coherence properties of supercontinuum spectra has been numerically investigated by solving the generalized nonlinear Schrödinger equation and using the complex degree of coherence theory. First, the effect of third-order dispersion on the coherence properties of supercontinuum spectra generated by soliton fission and soliton self-frequency shift has been investigated. The results show that if the group velocity dispersion values at the pump wavelength are identical and under the identical pumping conditions, negative third-order dispersion can cause much larger intensity fluctuations and wavelength jitters at the red edge of generated solitons than positive third-order dispersion, resulting in higher coherence degradation. Then the effect of negative third-order dispersion on the coherence properties of supercontinuum spectra generated by soliton fission and soliton self-frequency shift compensation has also been investigated. When at low input laser peak powers, due to the combined effects of modulation instability, negative third-order dispersion and the second zero-dispersion wavelength, the coherence depending on the input laser peak power decreases steeply first and then increases. When at high input laser peak powers, the modulation instability, negative third-order dispersion and soliton collision significantly contribute to the coherence degradation. The second zero-dispersion wavelength cannot stabilize the red-shifted solitons.
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