DocumentCode :
350479
Title :
Nonlinear phase shift experienced by ultrafast optical pulses propagating in quadratic medium
Author :
Seok-Kyoung Kang ; Myoungsik Cha
Author_Institution :
Res. Center for Dielectr. & Adv. Matter Phys., Pusan Nat. Univ., South Korea
Volume :
3
fYear :
1999
fDate :
Aug. 30 1999-Sept. 3 1999
Firstpage :
642
Abstract :
Self-phase modulation (SPM) due to the second order cascading effect has been studied extensively because of their potential for all-optical switching applications. In second harmonic generation (SHG), for example, a large nonlinear phase shift can accumulate in the fundamental wave (FW) when light is upconverted to its second harmonic (SH) and then is subsequently downconverted back. Such an effect is known to be at least two orders of magnitude larger than the Kerr-type SPM. However, problems such as temporal and spectral broadening exist in dealing with ultrafast optical pulses propagating in dispersive quadratic media. Among these, the temporal walk-off between the FW and the SH pulses caused by the group velocity mismatch (GVM) is the most significant hurdle, which results in a poor cascading efficiency. On the other hand, spatial solitary waves were observed in a KTP crystal, in which both of the diffraction and the spatial walk-off were compensated by the cascaded self-focusing effect. As a temporal analogue, one can consider the possibility of temporal solitons in the context that the GVM and the group velocity dispersion (GVD) are properly balanced by the cascaded SPM. In the present work, we numerically study ultrafast pulse propagation in a medium with both GVD and GVM near phase matching condition for SHG. We also propose novel methods for reducing these effects for ultrafast all-optical switching applications.
Keywords :
coupled mode analysis; high-speed optical techniques; light propagation; lithium compounds; optical harmonic generation; optical materials; optical phase matching; optical solitons; optical switches; self-phase modulation; KTP; KTP crystal; KTiOPO4; Kerr-type self-phase modulation; LiNbO/sub 3/; SHG; all-optical switching applications; cascaded self-focusing effect; cascading efficiency; diffraction; dispersive quadratic media; downconverted light; fundamental wave; group velocity dispersion; group velocity mismatch; nonlinear phase shift; optical pulse propagation; phase matching condition; quadratic medium; second harmonic; second harmonic generation; second order cascading effect; self-phase modulation; spatial solitary waves; spatial walk-off; spectral broadening; temporal analogue; temporal broadening; temporal solitons; temporal walk-off; ultrafast all-optical switching applications; ultrafast optical pulse propagation; ultrafast optical pulses; ultrafast pulse propagation; upconverted light; Dispersion; Nonlinear optics; Optical distortion; Optical propagation; Optical pulses; Optical refraction; Optical variables control; Optimized production technology; Pulse shaping methods; Scanning probe microscopy;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Lasers and Electro-Optics, 1999. CLEO/Pacific Rim '99. The Pacific Rim Conference on
Conference_Location :
Seoul, South Korea
Print_ISBN :
0-7803-5661-6
Type :
conf
DOI :
10.1109/CLEOPR.1999.817760
Filename :
817760
Link To Document :
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