Low-loss Sb$_2$S$_3$ Optical Phase Shifter Enabled by Optimizing Sputtering Conditions

Yuto Miyatake; Tomohiro Anda; Yosuke Wakita; Kotaro Makino; Shogo Hatayama; Makoto Okano; Kasidit Toprasertpong; Shinichi Takagi; Mitsuru Takenaka

arXiv · 2505.10752

Low-loss Sb$_2$S$_3$ Optical Phase Shifter Enabled by Optimizing Sputtering Conditions

Yuto Miyatake·Tomohiro Anda·Yosuke Wakita·Kotaro Makino·Shogo Hatayama·Makoto Okano·Kasidit Toprasertpong·Shinichi Takagi·Mitsuru Takenaka

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Abstract

By quantitatively evaluating the atomic concentrations of sputtered Sb$_2$S$_3$ films with different sputtering powers and Ar flows, we reveal that a sputtered Sb$_2$S$_3$ film becomes close to the stoichiometric composition as the sputtering power and Ar flow decrease. We characterize the optical properties of Sb$_2$S$_3$ and show that the lower sputtering power leads to a better figure of merit of Sb$_2$S$_3$ as an optical phase shifter in the near infrared (NIR) range. Based on these results, we achieve a loss per phase shift of 0.33 dB/$\pi$ at a wavelength of 1.55 $\mu$m, one of the lowest losses among Sb$_2$S$_3$ phase shifters in the NIR range.

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Yuto Miyatake, Tomohiro Anda, Yosuke Wakita, Kotaro Makino, Shogo Hatayama, Makoto Okano, Kasidit Toprasertpong, Shinichi Takagi, Mitsuru Takenaka. 2025-05-15. Low-loss Sb$_2$S$_3$ Optical Phase Shifter Enabled by Optimizing Sputtering Conditions. https://arxiv.org/abs/2505.10752

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