High-performance germanium (Ge) waveguide photodetectors are designed and fabricated utilizing the inductive-gain-peaking technique. With the appropriate integrated inductors, the 3-dB bandwidth of photodetectors is significantly improved owing to the inductive-gain-peaking effect without any compromises to the dark current and optical responsivity. Measured 3-dB bandwidth up to 75 GHz is realized and clear open eye diagrams at 64 Gbps are observed. In this work, the relationship between the frequency response and large signal transmission characteristics on the integrated inductors of Ge waveguide photodetectors is investigated, which indicates the high-speed performance of photodetectors using the inductive-gain-peaking technique.High-performance germanium (Ge) waveguide photodetectors are designed and fabricated utilizing the inductive-gain-peaking technique. With the appropriate integrated inductors, the 3-dB bandwidth of photodetectors is significantly improved owing to the inductive-gain-peaking effect without any compromises to the dark current and optical responsivity. Measured 3-dB bandwidth up to 75 GHz is realized and clear open eye diagrams at 64 Gbps are observed. In this work, the relationship between the frequency response and large signal transmission characteristics on the integrated inductors of Ge waveguide photodetectors is investigated, which indicates the high-speed performance of photodetectors using the inductive-gain-peaking technique.

GeSn detectors have attracted a lot of attention for mid-infrared Si photonics, due to their compatibility with Si complementary metal oxide semiconductor technology. The GeSn bandgap can be affected by Sn composition and strain, which determines the working wavelength range of detectors. Applying the Sn content gradient GeSn layer structure, the strain of GeSn can be controlled from fully strained to completely relaxed. In this work, the strain evolution of GeSn alloys was investigated, and the effectiveness of gradually increasing Sn composition for the growth of high-Sn-content GeSn alloys was revealed. Relaxed GeSn thick films with Sn composition up to 16.3% were grown, and GeSn photodetectors were fabricated. At 77 K, the photodetectors showed a cutoff wavelength up to 4.2 μm and a peak responsivity of 0.35 A/W under 1 V at 2.53 μm. These results indicate that GeSn alloys grown on a Sn content gradient GeSn structure have promising application in mid-infrared detection.

硅材料在1.1~8.5 μm有非常低的吸收损耗，因此硅基光电子学有望扩展到中红外波段。并且随着通信窗口扩展、气体分子检测、红外成像等应用需求的出现，硅基中红外波段器件研发工作的开展势在必行。在中红外波段硅基光电子器件中，硅基调制器有着举足轻重的地位：它是长波光通信链路中不可或缺的一环，还可以应用在片上传感系统中提高信噪比、实现光开关等功能。研究发现，相比于近红外波段，硅和锗材料在中红外波段有更强的自由载流子效应和热光效应，因此，基于硅基材料的中红外调制器具有独天得厚的优势。系统总结了中红外硅基调制器的发展趋势和研究现状，介绍了基于硅和锗材料的电光调制器以及热光调制器的工作原理和最新研究进展，最后对中红外硅基调制器进行了总结与展望。

A high-speed evanescent-coupled Ge waveguide electro-absorption modulator (EAM) with simple fabrication processes was realized on a silicon-on-insulator platform with a 220 nm top Si layer. Selectively grown Ge with a triangle shape was directly used for Ge waveguides of the EAM. An asymmetric p-i-n junction was designed in the Ge waveguide to provide a strong electric field for Franz–Keldysh effect. The insertion loss of the Ge EAM was 6.2 dB at 1610 nm. The EAM showed the high electro-optic bandwidth of 36 GHz at -1V. Clear open 56 Gbps eye diagrams were observed at 1610 nm with a dynamic extinction ratio of 2.7 dB and dynamic power consumption of 45 fJ/bit for voltage swing of 3V_pp.