Self-phase modulation in photonic-crystal-slab line-defect waveguides

The authors observed self-phase modulation in spectral domain at 1.50 mu m in AlxGa1-xAs-based photonic-crystal-slab line-defect waveguides. Adopting a sample with x=0.18 has enabled the authors to avoid two-photon absorption, causing undesirable free-carrier-induced refractive-index change. Variation of the observed spectrum with input pulse peak power is well reproduced by theoretical simulation. They find that a 1.6 ps light pulse of 2.5 pJ suffices for causing a phase shift of pi in a 1 mm long sample owing to tight light confinement and nonlinear refractive index n(2) due to instantaneous optical Kerr effect is (3.8 +/- 1.2)x10(-13) cm(2)/W. A possibility of developing ultrafast all-optical switch due to n(2) is discussed (c) 2007 American Institute of Physics.