The numerical investigations of SiGe/Si heterojunction electro-optic modulator in mid-infrared

• Published in: Frontiers in physics 2022-11, Vol.10
• Main Authors: Feng, Song, Hu, Xiangjian, Feng, Lulu, Wang, Di, Chen, Menglin, Liu, Yong, Hu, Heming, Jia, Lianxi
• Format: Article
• Language: English
• Subjects: electro-optic modulator; mach-zehnder modulator; mid-infrared; SiGe/Si heterojunction; silicon on insulator
• ISSN: 2296-424X; 2296-424X
• DOI: 10.3389/fphy.2022.1019113

We present the detailed numerical analysis and characterization of SiGe/Si heterojunction electro-optic modulator at 2 μm, 4.3 μm, and 5 μm wavelengths. We investigate the band, the refractive index, and the carrier injection efficiency of SiGe/Si heterojunction PIN electrical structure. Numerical investigations are carried out on the key geometrical parameters, doping concentration, Ge content. The results show that the modulated voltage of SiGe/Si PIN heterojunction modulator is lower 50% than that of Si modulator under the same modulation effect. In order to eliminate the absorption losses of SiO 2 in mid-infrared, the punch Mach–Zehnder optical structure is established and researched. The research present that the modulator has the short 500 µm phase shifters and the low V π L π of 0.042 Vcm under forward bias voltage, and the extinction ratio is greater than 12.81 dB. The high-speed transmission characteristics are shown to have clean eye diagrams up to 40 Gbps in mid-infrared.