Broadband supercontinuum generation in nitrogen-rich silicon nitride waveguides using a 300  mm industrial platform

Abstract

We report supercontinuum generation in nitrogen-rich (N-rich) silicon nitride waveguides fabricated through back-end complementary-metal-oxide-semiconductor (CMOS)-compatible processes on a 300 mm platform. By pumping in the anomalous dispersion regime at a wavelength of 1200 nm, two-octave spanning spectra covering the visible and near-infrared ranges, including the O band, were obtained. Numerical calculations showed that the nonlinear index of N-rich silicon nitride is within the same order of magnitude as that of stoichiometric silicon nitride, despite the lower silicon content. N-rich silicon nitride then appears to be a promising candidate for nonlinear devices compatible with back-end CMOS processes.

On-Chip Mid-Infrared Supercontinuum Generation from 3 to 13 μm Wavelength

“…In order to locate the dispersive waves (DW) on the generated spectrum, the integrated dispersion (β int ) is calculated for a 7.5 μm pump wavelength at different pump peak power values, as shown in Figure . The crossing with zero (horizontal dashed line) indicates the phase-matching condition that promotes the DW generation . The wide anomalous dispersion profile achieved leads to a large separation of the DW from the pump wavelength (near 3.5 and 19 μm), thus, enlarging the output spectrum up to more than two octaves.…”

“…Numerical modeling has been implemented to have a better understanding of the experimental results and to get insights of the SCG limiting factors. The modeling is based on the resolution of the generalized nonlinear Schrödinger equation (GNLSE) 22 , 33 by using a 4-order Runge–Kutta algorithm. 34 For such simulations, the pump pulse shape is assumed to be a squared hyperbolic secant (sech 2 ), the nonlinear Kerr refractive index 29 ( n 2 ) is taken to be 1 × 10 –17 m 2 /W, and the dispersion profile is calculated through an eigenmode solver software ( Figure 1 b).…”

“…The crossing with zero (horizontal dashed line) indicates the phase-matching condition that promotes the DW generation. 22 The wide anomalous dispersion profile achieved leads to a large separation of the DW from the pump wavelength (near 3.5 and 19 μm), thus, enlarging the output spectrum up to more than two octaves. The generated DW near 3.5 μm for the pump wavelength of 7.5 μm is visible in both experimental and simulated spectra ( Figure 3 a,c), while the noise level prevents seeing experimentally any signal beyond a 14 μm wavelength.…”

“…On another hand, in terms of photonics integration, silicon (Si) photonics presents strong advantages, as it is based on a mature and large-scale fabrication technology. Hence, SCG has been demonstrated on Si-on-insulator, , Si-on-sapphire, silicon nitride (SiN), − and germanium (Ge)-based waveguides. − Interestingly, Ge-rich graded SiGe waveguides have been proposed as a promising solution for mid-IR photonic circuits in which low-loss devices have been experimentally demonstrated for a large wavelength range . The use of SiGe graded-index layers is a unique feature that minimizes the overlap with Si substrate, thus, enabling the use of long-wave mid-IR wavelengths above Si multiphonon absorption (starting at 8.5 μm wavelength).…”

ADVANCED PROGRESS ON Χ<SUP>(3)</SUP> NONLINEARITY IN CHIP-SCALE PHOTONIC PLATFORMS (INVITED REVIEW)

“…In 2019, Liu et al experimentally generated a VR to NIR SC spanning from 600 to 1050 nm in AlN waveguides [65]. Lafforgue et al experimentally exploited nitrogen-rich Si 3 N 4 waveguides to generate an octave SC spanning from 400 to 1600 nm [66]. Numerical simulations indicated high interpulse coherence of generated SC.…”