Supercontinuum Generation And Pulse Compression Based On Integrated Silicon Photonic Optical Waveguides

Silicon-based optical waveguides have strong optical confinement and are compatible with complimentary metal-oxide semiconductor(CMOS)processes.Silicon photonic waveguides are widely used for integrated functional devices and become the backbone of large-scale optoelectronic integrated circuits in the future.In order to obtain on-chip integrated mid-IR broadband coherent optical sources,ultrashort pulse compressors and optical parametric amplifiers,we propose novel waveguide structures composed of proper Group IV materials.These waveguides can generate wideband low and flat dispersion,which can be used for supercontinuum generation covering the whole spectral range of interest,pulse compression to a subcycle level with a high-quality waveform,and optical parametric amplification with an octave-spanning gain spectrum.For the supercontinuum generation,slot waveguides can be used to engineer dispersion in the near-infrared(near-IR)and realize near-IR supercontinuum generation.However,the transparent windows of the low-index materials for the slot limits the bandwidth of the mid-infrared(mid-IR)supercontinuum.We choose germanium and silicon as waveguide core materials,which have high nonlinearities,wider transparent windows in mid-IR and are compatible with CMOS processes.The designed bilayer waveguide can generate flat and low dispersion which spans two octaves in the mid-IR.We establish the model of nonlinear transmission and obtain a mid-IR supercontinuum for the integrated broadband and coherent optical source pumped by a sub-ps pulse.For the pulse compression,using a single-stage slot waveguide and a bilayer waveguide,we can generate a sub-cycle pulse and a high-quality pulse with low pedestals,respectively.We propose a novel scheme for monitoring the carrier-envelope phase precisely on the same chip.We also study the mechanism of pedestal suppression and choose the optimum pump condition to realize high-quality pulse compression.For the optical parametric amplification,we choose silicon-rich nitride with strong nonlinearity for the waveguide design and propose a novel bilayer waveguide to engineer dispersion.By investigating the broadband phase matching condition in the dual-pump scheme,we can realize broadband optical parametric amplification.