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Direct thermo-optical tuning of silicon photonic devices (Conference Presentation)
Author(s): Paul Chevalier; Lara Koehler; Euijae Shim; Boris Desiatov; Amirhassan Shams-Ansari; Marco Piccardo; Marko Loncar; Michal Lipson; Alexander Gaeta; Federico Capasso

Paper Abstract

Thanks to its high Kerr non-linearity and its low linear absorption, silicon is a material of choice for optical devices in the mid-infrared (from 3 to 5 microns) such as microresonators. In this wavelength range, the available optical sources such as quantum cascade lasers have a limited tunability. Tuning the refractive index of silicon can be achieved by a temperature change of the chip and has been previously demonstrated on ring resonators using integrated heaters or thermo-electric elements. We present a new method for thermo-optical tuning of silicon devices by directly using the light from a laser diode operating at 450 nm. The blue light focused on the silicon induces a local elevation of temperature and thus the refractive index locally increases. When applying this method on silicon ring resonator, the elevation of temperature leads to a decreasing free-spectral range and thus shift the resonances to lower frequencies. At 4.5 µm we measured a tuning efficiency of 200 MHz per mW of incident light. Numerical simulations of the thermo-optical effect show the locality of this tuning method, and confirm the experimental results. Finally a frequency study of the response of this method is performed and a time constant of the order of the micro-second is measured. In conclusion, we propose a fast, local, and non-invasive method for tuning silicon resonators operating in the mid-infrared that can be extended to any silicon-based device.

Paper Details

Date Published: 4 March 2019
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Proc. SPIE 10923, Silicon Photonics XIV, 1092309 (4 March 2019); doi: 10.1117/12.2510421
Show Author Affiliations
Paul Chevalier, Harvard Univ. (United States)
Lara Koehler, Harvard Univ. (United States)
Ecole Polytechnique (France)
Euijae Shim, Columbia Univ. (United States)
Boris Desiatov, Harvard Univ. (United States)
Amirhassan Shams-Ansari, Harvard Univ. (United States)
Marco Piccardo, Harvard Univ. (United States)
Marko Loncar, Harvard Univ. (United States)
Michal Lipson, Columbia Univ. (United States)
Alexander Gaeta, Columbia Univ. (United States)
Federico Capasso, Harvard Univ. (United States)


Published in SPIE Proceedings Vol. 10923:
Silicon Photonics XIV
Graham T. Reed; Andrew P. Knights, Editor(s)

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