Dispersion-optimized multicladding silicon nitride waveguides for nonlinear frequency generation from ultraviolet to mid-infrared

Abstract

Nonlinear frequency conversion spanning from the ultraviolet to the mid-infrared (beyond 2.4 μm) is experimentally\ud demonstrated in multicladding silicon nitride (SiXNY ) waveguides. By adjusting the waveguide cross-section\ud the chromatic dispersion is flattened, which enhances both the efficiency and the bandwidth of the nonlinear conversion.\ud How accurately the dispersion is tailored is assessed through chromatic dispersion measurements and an\ud experiment/simulation comparison of the dispersive waves’ wavelength locations. Undesirable fluctuations of both\ud the refractive index and the dimensions of the waveguide during the fabrication process result in a dispersion unpredictability\ud of at least 20 ps/nm/km. Finally, manipulation of the effective refractive index allows for multiple third\ud harmonic generated tones spanning from 381 to 715 nm

Supercontinuum generation in dispersion engineered AlGaAs-on-insulator waveguides

“…In future devices, the incorporation of tapers 39 , higher order modes 40 , and choice of upper cladding 41 could also be investigated for dispersion engineering purposes thus providing a multitude of new design parameters to expand and optimize SCG.The incorporation of inverse taper couplers could also improve the coupling efficiency of the device and avoid the possible excitation of higher order modes, whilst microring resonators could be used to enhance observed nonlinearities. Moreover the strong of AlGaAs and its corresponding second harmonic signal, lends themselves to applications requiring f-2f referencing 42 and highlights the potential of AlGaAs-OI for examining the interplay of second and third order nonlinearities within a single material platform.…”

Dispersion-engineered silicon nitride waveguides for mid-infrared supercontinuum generation covering the wavelength range 0.8–6.5 μm

“…The Si 3 N 4 waveguide can be fabricated by employing two different deposition techniques such as low pressure chemical vapor deposition technique (LPCVD) and plasma enhanced vapor deposition technique [28,[39][40][41][42]. Although the stoichiometry variation of the Si 3 N 4 film provides an additional degree of freedom in waveguide fabrication, the high film stress of this material prevents the waveguide fabrication with a thickness more than 400 nm resulting in cracks formation on the Si 3 N 4 film [40].…”