[OPTICAL REVIEW Vol. 9, No. 3 (2002) 89-93]

Modal Birefringence Dependent Supercontinuum Due to Cross-Phase Modulation in a Dispersion-Flattened/Decreasing Fiber

Hiroyasu SONE1,2,*, Tasuku ARAI1, Masaaki IMAI1 and Yoh IMAI3,†

1Department of Electrical and Electronic Engineering, Muroran Institute of Technology, 27-1 Mizumoto-cho, Muroran, 050-8585 Japan 2Department of Computer Science, Kitami Institute of Technology, 165 Kouen-cho, Kitami, 090-8507 Japan 3Department of Computer Science and Electronics, Kyushu Institute of Technology, 680-4, Kawazu, Iizuka, 820-8502 Japan

(Received February 4, 2002; Accepted March 15, 2002)

It was found by numerical analysis that a 320 nm wide and flat spectrum at 20 dB less than the central maximum intensity is generated from cross-phase modulated soliton pulses with 3.5 ps pulse width and 2.3 W peak power, which are propagated through a 2.4 km length of dispersion-flattened/decreasing fiber (DFDF). The cross-phase modulation (XPM) at a central wavelength of 1.55 μm is achieved by exciting two orthogonally polarized modes into the principal axes. The wave-vector mismatch between the orthogonal pulses can be neglected because of soliton trapping when the modal birefringence of the DFDF is less than |n0x−n0y|=10-6. The effect of modal birefringence on supercontinuum generation is discussed in temporal and spectral regimes by numerical analysis.

Key words: nonlinear fiber optics, optical soliton propagation, cross-phase modulation (XPM), modal birefringence, supercontinuum spectrum, dispersion-flattened/decreasing fiber