Multimode nonlinear optics and its application in supercontinuum source and all-optical signal processing

We show two of our work on multi-mode nonlinear optical process. In a Ta₂O₅ waveguide of 100 nm in thickness, 8 μm in width and 4.3 mm in length, all-optical signal switching and power limiting operation were demonstrated by nonlinear multi-mode interference while the modes were properly excited by a near infrared pulse at the wavelength of 1064 nm, peak power of 100 W and the pulse duration of 1 ps. In supercontinuum process, a waveguide of 760 nm in thickness and 1.1 μm in width was designed where different guided modes were anomalously dispersive at different wavelengths. Supercontinuum spectrum spanning over an octave with high degree of spectral flatness was excited by a 100-fs laser pulse at the wavelength of 1030 nm. Spectral synthesis with a diffraction gratings mapped the spectral components attributed to specific waveguide modes. It inferred the possibility to engineer supercontinuum generation through waveguide-mode arrangement.