Thermal and Kerr nonlinear properties of plasma-deposited silicon nitride/ silicon dioxide waveguides

Abstract

We introduce and present experimental evaluations of loss and nonlinear optical response in a waveguide and an optical resonator, both implemented with a silicon nitride/ silicon dioxide material platform prepared by plasma-enhanced chemical vapor deposition with dual frequency reactors that significantly reduce the stress and the consequent loss of the devices. We measure a relatively small loss of approximately 4dB/cm in the waveguides. The fabricated ring resonators in add-drop and all-pass arrangements demonstrate quality factors of Q=12,900 and 35,600. The resonators are used to measure both the thermal and ultrafast Kerr nonlinearities. The measured thermal nonlinearity is larger than expected, which is attributed to slower heat dissipation in the plasma-deposited silicon dioxide film. The n2 for silicon nitride that is unknown in the literature is measured, for the first time, as 2.4 x 10(-15)cm(2)/W, which is 10 times larger than that for silicon dioxide.

New CMOS-compatible platforms based on silicon nitride and Hydex for nonlinear optics

“…The first nonlinear optical studies of SiN waveguides were reported in 2008 [55] (Fig. 1a), showing nonlinear shifting of the resonances in 700 nm thick SiN ring resonators obtained with 200 mW CW optical pump power.…”

“…However, only recently [55] it has been proposed as a platform for nonlinear optics. Historically, the challenge for SiN optical devices has been to grow low loss layers thicker than 250 nm, due to tensile film stress.…”

“…Achieving such thick layers is critical for nonlinear optics since both high mode confinement as well as dispersion engineering for phase matching [57] are needed. Thick (>500 nm) low loss SiN layers were recently grown ( Figure 1) by plasma-enhanced chemical vapor deposition (PECVD) [55] as well as by low-pressure chemical vapor deposition (LPCVD) [57]. The latter approach employed a thermal cycling process that resulted in very thick (700 nm) films that yielded nanowires with very low propagation loss (0.4 dB/cm).…”

“…This review focuses on new platforms recently introduced [55][56][57][58][59] for nonlinear optics that have achieved considerable success and that also offer CMOS compatibility. They are based on silicon nitride (Si 3 N 4 ) and high-index doped silica (trade-named Hydex).…”

Sideband pump-probe technique resolves nonlinear modulation response of PbS/CdS quantum dots on a silicon nitride waveguide

“…[30][31][32] Additionally, a range of hybrid photonic devices based on silicon nitride structures has been demonstrated. 10,[33][34][35][36][37] In contrast to pure silicon, the material does not display large intrinsic nonlinearities or a substantial free carrier absorption 38 and therefore allows us to observe the nonlinear response of the QDs without waveguide-induced background. A schematic of the sample is displayed in Fig.…”