In situ Thermal Trimming of Waveguides in a Standard Active Silicon Photonics Platform

Fuente: arXiv
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Main Authors: Xue, Tianyuan, Wahn, Hannes, Stalmashonak, Andrei, Poon, Joyce K. S., Sacher, Wesley D.
Format: Preprint
Published: 2025
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author Xue, Tianyuan
Wahn, Hannes
Stalmashonak, Andrei
Poon, Joyce K. S.
Sacher, Wesley D.
author_facet Xue, Tianyuan
Wahn, Hannes
Stalmashonak, Andrei
Poon, Joyce K. S.
Sacher, Wesley D.
contents We present suspended heater structures fabricated in a standard C- and O-band silicon (Si) photonics platform that can achieve sufficiently high local temperatures to induce effective refractive index trimming of Si and silicon nitride (SiN) waveguides with 30 - 90 mW of applied electrical power. Following thermal trimming at moderate powers ($\leq$ 40 mW), maximum changes in the averaged waveguide effective refractive index of $-5.18 \times 10^{-3}$ and $-7.9 \times 10^{-4}$ are demonstrated in SiN and Si waveguides, respectively, at a wavelength of 1550 nm. At higher powers, SiN waveguides exhibit positive averaged effective index changes up to $\approx$0.02, demonstrating bi-directional index trimming. As an example application, we demonstrate bias point trimming of a carrier injection Mach-Zehnder switch. Through investigations of the origin of the thermal trimming effect, we hypothesize that changes in the silica (SiO$_2$) waveguide cladding may be a primary underlying mechanism at temperatures $\gtrsim$300$^{\circ}$C, with significant trimming of SiN waveguide cores occurring at larger temperatures $\gtrsim$510$^{\circ}$C. As the trimming experiments represent a form of accelerated thermal aging, we estimate the aging behavior of the suspended heaters by fitting and extrapolating the measured datasets to 100 - 200$^{\circ}$C operating temperatures over five years.
format Preprint
id arxiv_https___arxiv_org_abs_2506_13578
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle In situ Thermal Trimming of Waveguides in a Standard Active Silicon Photonics Platform
Xue, Tianyuan
Wahn, Hannes
Stalmashonak, Andrei
Poon, Joyce K. S.
Sacher, Wesley D.
Optics
Applied Physics
We present suspended heater structures fabricated in a standard C- and O-band silicon (Si) photonics platform that can achieve sufficiently high local temperatures to induce effective refractive index trimming of Si and silicon nitride (SiN) waveguides with 30 - 90 mW of applied electrical power. Following thermal trimming at moderate powers ($\leq$ 40 mW), maximum changes in the averaged waveguide effective refractive index of $-5.18 \times 10^{-3}$ and $-7.9 \times 10^{-4}$ are demonstrated in SiN and Si waveguides, respectively, at a wavelength of 1550 nm. At higher powers, SiN waveguides exhibit positive averaged effective index changes up to $\approx$0.02, demonstrating bi-directional index trimming. As an example application, we demonstrate bias point trimming of a carrier injection Mach-Zehnder switch. Through investigations of the origin of the thermal trimming effect, we hypothesize that changes in the silica (SiO$_2$) waveguide cladding may be a primary underlying mechanism at temperatures $\gtrsim$300$^{\circ}$C, with significant trimming of SiN waveguide cores occurring at larger temperatures $\gtrsim$510$^{\circ}$C. As the trimming experiments represent a form of accelerated thermal aging, we estimate the aging behavior of the suspended heaters by fitting and extrapolating the measured datasets to 100 - 200$^{\circ}$C operating temperatures over five years.
title In situ Thermal Trimming of Waveguides in a Standard Active Silicon Photonics Platform
topic Optics
Applied Physics
url https://arxiv.org/abs/2506.13578