Electroabsorption Modulator Schemes Based on Uniaxial Tensioned Germanium / Silicon Germanium Multiple Quantum Wells
Due to the serious power consumption and bandwidth constraints of the development of large scale integrated circuits, on-chip interconnection has been considered as a potential development path. Silicon photonics is the most suitable platform for integrating optics and electronics, but is constrained by active devices. Germanium and silicon germanium alloy materials have received more and more attention recently. This is due to the fact that the direct bandgap energy of germanium corresponds to a wavelength in the C band, whereas the indirect bandgap L valley edge is only 140 eV below the direct bandgap Γ valley. Researchers have proposed and developed various CMOS-compatible methods to change the band structure of germanium-related materials, including germanium / silicon germanium quantum wells, vacant germanium microstructures, and germanium-tin alloys. In the silicon-based modulator field, Germanium / silicon germanium quantum well electro-absorption modulator has the advantages of small size and low power consumption. Due to the quantum confinement effect, the direct bandgap absorption energy of the germanium / silicon germanium quantum well is larger than that of the germanium material. The previous 10 nm wide germanium quantum well operates at zero bias voltage at 1420 nm. Although the absorption edge can be regulated by applying a different bias voltage, the absorption contrast also deteriorates with increasing bias voltage. Higher bias voltage is not suitable for large-scale integration. Thus, the operating wavelength of germanium / silicon germanium multiple quantum well electroabsorption modulator is limited. Wuhan Optoelectronics National Laboratory Optoelectronic Devices and Integrated Functional Laboratory Professor Sun Junqiang lead doctoral students such as Gao Jian-feng proposed a uniaxial tensile strained germanium / silicon germanium multi-quantum well electroabsorption modulator scheme. The scheme greatly broadens the working wavelength range of the electroabsorption modulator of the germanium / silicon germanium multi-quantum well, and can improve the absorption contrast of the TE mode. By introducing a uniaxial tensile strain of 0.18% -1.6%, a zero-bias electroabsorption modulator covering a wavelength range of 1380-1550 nm can be fabricated on a 10/12 nm Ge / Si 0.19 Ge 0.81 chip. For waveguide applications, uniaxial tensile strain germanium / silicon germanium quantum wells have enhanced TE absorption contrast and suppressed TM absorption. At 1.6% uniaxial tensile strain and 0V / 2V operating voltage, the TE absorption contrast was increased by 3.1 dB and the TM absorption coefficient was reduced by two thirds. The enhanced TE absorption contrast and wide operating wavelength range make the device ideal for waveguide integration and high-efficiency modulation applications. The research result "Design and analysis of electro-absorbing modulators with uniaxially stressed Ge / SiGe multiple quantum wells", published May 2, 2017, is published in OSA's Journal Optics Express (Vol.25, No.10, pp. , 2017) magazine. The research was funded by the National Natural Science Foundation of China (61435004). (A) Ge / SiGe multiple quantum well structure. (B) Schematic diagram of the structure of an electroabsorption modulator based on a suspended micro-bridge. (C) Stereo tensor εxx distribution. (D) The xy plane strain tensor εxx (E) Mode field component Ey distribution of quasi-TE fundamental mode at 1550 nm wavelength. Aluminium Profile,Aluminium Rectangular Tube Profile,Aluminium Extruded Profile,Anodizin Aluminium Profile KAM KIU ALUMINIUM GROUP , https://www.taishankamkiu.com