The Thermo Optic Coefficient of Amorphous SiN Films in the Near-Infrared and Visible Regions and Its Experimental Determination

Abstract

The thermo optic coefficient (TOC) of amorphous SiN thin films was determined by means of an alternative experimental approach. According to the method, it was possible to obtain the TOC of SiN at approximately 1510 nm and at 620 nm corresponding to the near-infrared (NIR) and visible (VIS) transmission windows typically observed in silica- and polymer-based optical fibers, respectively. The method relies on light transmission measurements of optical micro cavities (with SiN films as spacer layers) in the 83–873 K temperature range. Following this approach, the room-temperature TOC of SiN was found to be (4.7±0.1)×10-5 K-1 in the NIR and (6.2±0.1)×10-5 K-1 in the VIS regions.

Thermo-Optic Characterization of Silicon Nitride Resonators for Cryogenic Photonic Circuits

“…The presented work nicely complements the reported data for room temperature measurements and higher. On the otherhand, we see that the sputtered SiN in [14] provides a slightly higher thermo-optic coefficient at visible and near infra-red range, which may be attributed to different silicon content in the sample, generally, the thermo-optic coefficient depends on the operating wavelength and the material composition. For the presented measurements, we used a silicon nitride deposition process that is similar to the work in [27].…”

“…Based on integrated waveguide-technique, the room temperature thermo-optic coefficient SiN was previously reported [5], [12], [13]. Low temperature values of the thermo-optic coefficient were only reported for amorphous SiN down to 80 K using Fabry-Pèrot measurements [14]. Based on the fitted data, a numerical model was constructed, but unfortunately the model breaks-down below 50 K. While characterization at even lower temperatures is highly desired for on-chip quantum photonic applications, no detailed study of the thermo-optic properties of the material at low temperatures have been performed.…”

Characterization of the temperature dependence of the thermoreflectance coefficient for conductive thin films

“…Room temperature optical data (n f , n m , ∂n f ∂T ) are estimated from the literature. [23][24][25] This figure demonstrates that the thermoreflectance coefficient of a material may be optimized through selective deposition of passivation layer thickness or by utilizing incident illumination wavelength coincident with a maximum. The influence of passivation thickness on the thermoreflectance coefficient of platinum is qualitatively different for the sample under 470 nm illumination relative to the other metals; though, this asymmetric and bipolar dependency on dielectric layer thickness has been observed elsewhere.…”

Si Photonics for Practical LiDAR Solutions

“…]. 2 These data are obtained from Ref [30][31][32][33][34][35][36][37]. at around 1550 nm wavelength.…”