Science Building Texas Tech University, Physics & Astronomy Department, Box 41051, Lubbock, TX 79409-1051 Kim, “Extremely high dispersions in heterogeneously coupled waveguides,” Opt. Carlson et al., “Photonic-chip supercontinuum with tailored spectra for counting optical frequencies,” Phys. Johnson et al., “Octave-spanning coherent supercontinuum generation in a silicon nitride waveguide,” Opt. Kim et al., “Dispersion engineering and frequency comb generation in thin silicon nitride concentric microresonators,” Nat. Zhang et al., “Flat and low dispersion in highly nonlinear slot waveguides,” Opt. Zhang et al., “Silicon waveguide with four zero-dispersion wavelengths and its application in on-chip octave-spanning supercontinuum generation,” Opt. Qi, “Broadband second-harmonic phase-matching in dispersion engineered slot waveguides,” Opt. In the case of the anomalous regime, the span of the SC gets higher due to the soliton dynamics, and an addition DW on the short wavelength side is generated. Since we have now multiple numbers of ZDWs, in this case, 8, the scope of changing the pumping wavelength is also feasible. We pumped in a way that one ZDW is at one side of the source and the rest of them are on the other side. In the case of the normal regime, primarily we could observe two distinct dispersive waves (DWs) near the ZDWs. We have used a 260 pJ 200 femtosecond pulse as the source and pumped close to the zero-dispersion wavelengths (ZDWs) in both anomalous and normal dispersion regime. We used the split-step Fourier method to consider both the linear propagation effects- dispersion and loss, and the nonlinear propagation effect- nonlinearity. Moreover, to show how useful this dispersion profile can be, we have simulated a supercontinuum numerically using the well-known Schrodinger equation. The thin Si3N4 film thickness allows the structure to be compatible with the CMOS process, and its broadband near-zero dispersion profile is useful in on-chip supercontinuum generations (SCG). The resultant dispersion is within ☗0 ps/nm/km with eight zero-dispersion wavelengths over a bandwidth of 520 nm. Multiple mode couplings are introduced to engineer dispersions at four different wavelengths, covering the wavelengths of 1350 – 1800 nm. Here, we present a thin (300 nm) Si3N4 waveguide array design, which is compatible with the CMOS technology and achieves a broadband near-zero dispersion at near-infrared. Thus, for the full integration of Si3N4 devices with the CMOS foundry, an advanced dispersion engineering method is required on a thin Si3N4 waveguide. However, for a near-zero or anomalous dispersions at near-infrared, a thick Si3N4 film thickness (> 600 nm) is required, which is prone to crack due to its high film stress and is not compatible with the current complementary metal-oxide-semiconductor (CMOS) technology. Alternatively, silicon nitride (Si3N4) has a high nonlinearity and low two-photon absorption coefficient, and it has been widely used for Kerr frequency comb and supercontinuum generations. However, Si is not an ideal material for on-chip nonlinear processes as it has strong two-photon absorption. In earlier works, various silicon (Si) slot waveguides have been explored to achieve near-zero dispersion profiles. Among other dispersion profiles, a broadband near-zero dispersion is highly desired in many parametric processes such as supercontinuum and Kerr frequency comb generations, as it naturally matches the phases among other frequencies. A super continuum is also generated solving the nonlinear Schrodinger equation using the designed complementary metal-oxide-semiconductor technology compatible thin array of Silicon nitride waveguides.Ĭontrolling dispersions of a photonic waveguide is essential in many nonlinear optical processes, as it helps to satisfy the required phase-matching conditions for various frequency conversions. Multiple mode couplings are introduced at four different wavelengths by coupling different orders of modes. We present a thin silicon nitride waveguide array that achieves a broadband near-zero dispersion profile at near-infrared (1350 – 1800 nm).
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