Abstract
This work reports the integration of a ${{\rm Ge}_{1 - x}}{{\rm Sn}_x} {\text -} {\rm on} {\text -} {\rm AlN}$ optical waveguide (WG) on ${{\rm SiO}_2}$ substrate to facilitate mid-infrared (MIR) trace gas detection. Here, the proposed structure makes use of ${{\rm Ge}_{1 - x}}{{\rm Sn}_x}$ in the core of the WG and the AlN cladding; this enables the effective guidance and confinement of a broad spectrum of MIR light waves within the GeSn WG. The gas detection mechanism of the device is based on the evanescent wave field component of a guided mode to examine particular molecular absorption/trace gas characteristics of the upper cladding environment. The designed WGs exhibit high power confinement ($\sim 90\%$) and low propagation loss of 0.61–1.18 dB/cm at $\lambda = {4.3 {-} 4.74}\;{\unicode{x00B5}{\rm m}}$ with $x = \;{6}\%$ in the ${{\rm Ge}_{1\! -\! x}}{{\rm Sn}_x}$ core. We also discuss the capability of the proposed WG to detect trace gases such as CO, ${{\rm CO}_2}$, and ${{\rm N}_2}{\rm O}$. The results show that the minimum detectable concentrations (${C_{{\rm min}}}$) of these gases are ${\sim}{0.42}$, 0.12, and 0.16 ppm, respectively, for ${x} = {6}\%$. These encouraging results enable a new sensor platform for GeSn-based MIR trace/atmospheric gas detection.
© 2023 Optica Publishing Group
Full Article | PDF ArticleMore Like This
Harshvardhan Kumar, Tanisha Bohra, Apoorv Sharma, P. Susthitha Menon, and Agus Muhamad Hatta
J. Opt. Soc. Am. B 40(12) 3246-3254 (2023)
Xin Yu Li, Jia Yao Wang, Yu Fei Liu, Jing Jing Chen, Yan Du, Wei Wang, Yan Cai, Jian Ping Ma, and Ming Bin Yu
Appl. Opt. 59(25) 7646-7651 (2020)
Dong Zhang, Jie Liao, Pengjun Wang, Qiang Fu, Weiwei Chen, Shixun Dai, LiPeng Deng, Jun Li, Tingge Dai, and Jianyi Yang
J. Opt. Soc. Am. B 41(5) 1170-1179 (2024)