Xiao Hu 1,2Dingyi Wu 2Ye Liu 2Daigao Chen 1,2[ ... ]Shaohua Yu 1,2,3
Author Affiliations
Abstract
1 State Key Laboratory of Optical Communication Technologies and Networks, Wuhan Research Institute of Posts & Telecommunications (WRI), Wuhan 430074, China
2 National Information Optoelectronics Innovation Center, Wuhan 430074, China
3 Peng Cheng Laboratory, Shenzhen 518055, China
Based on the 90 nm silicon photonics commercial foundry, sidewall-doped germanium–silicon photodetectors (PDs) are designed and fabricated. The large designed overlap between the optical field and electric field achieves high responsivity while retaining high-speed performance. Even including the loss due to optical fiber coupling, the PD demonstrates an external responsivity greater than 0.55 A/W for transverse magnetic (TM) polarization and 0.65 A/W for transverse electric (TE) polarization at 1530 nm. A flat responsivity spectrum of >0.5 A/W is achieved up to 1580 nm for both polarizations. Their internal responsivities can exceed 1 A/W in the C+L optical communication bands. Furthermore, with the aid of a 200 mm wafer-level test and analysis, the overall PDs of 26 reticles have a 3 dB optoelectrical bandwidth >50 GHz and a dark current <10 nA at a -3 V bias voltage. Finally, the eye diagram performances under TE and TM polarizations, various modulation formats, and different input wavelengths are comprehensively investigated. The clear open electrical eye diagrams up to 120, 130, 140, and 150 Gbit/s nonreturn-to-zero are experimentally attained at a photocurrent of 1 mA. To the best of our knowledge, this is the first time that single-lane direct detection of record-high-speed 200, 224, 256, and 290 Gbit/s four-level pulse amplitude modulation (PAM) and 300, 336, 384, and 408 Gbit/s eight-level PAM optical signals has been experimentally achieved.
Photonics Research
2023, 11(6): 961
Daigao Chen 1,2†Hongguang Zhang 1†Min Liu 1Xiao Hu 1,2[ ... ]Xi Xiao 1,2,3,*
Author Affiliations
Abstract
1 National Information Optoelectronics Innovation Center, China Information and Communication Technologies Group Corporation (CICT), Wuhan 430074, China
2 State Key Laboratory of Optical Communication Technologies and Networks, China Information and Communication Technologies Group Corporation (CICT), Wuhan 430074, China
3 Peng Cheng Laboratory, Shenzhen 518055, China
A light-trapping-structure vertical Ge photodetector (PD) is demonstrated. In the scheme, a 3 μm radius Ge mesa is fabricated to constrain the optical signal in the circular absorption area. Benefiting from the light-trapping structure, the trade-off between bandwidth and responsivity can be relaxed, and high opto-electrical bandwidth and high responsivity are achieved simultaneously. The measured 3 dB bandwidth of the proposed PD is around 67 GHz, and the responsivity is around 1.05 A/W at wavelengths between 1520 and 1560 nm. At 1580 nm, the responsivity is still over 0.78 A/W. A low dark current of 6.4 nA is also achieved at -2 V bias voltage. Based on this PD, a clear eye diagram of 100 GBaud four-level pulse amplitude modulation (PAM-4) is obtained. With the aid of digital signal processing, 240 Gb/s PAM-4 signal back-to-back transmission is achieved with a bit error ratio of 1.6×10-2. After 1 km and 2 km fiber transmission, the highest bit rates are 230 and 220 Gb/s, respectively.
Photonics Research
2022, 10(9): 2165
Dingyi Wu 1,2Xiao Hu 1,2Weizhong Li 1,2Daigao Chen 1,2[ ... ]Xi Xiao 1,2
Author Affiliations
Abstract
1 Wuhan Research Institute of Posts and Telecommunications (WRI), Wuhan 430074, China
2 National Information Optoelectronics Innovation Center, China Information and Communication Technologies Group Corporation (CICT), Wuhan 430074, China
Abstract
Journal of Semiconductors
2021, 42(2): 020502
Author Affiliations
Abstract
1 National Information Optoelectronics Innovation Center, China Information and Communication Technologies Group Corporation (CICT), Wuhan 430074, China
2 State Key Laboratory of Optical Communication Technologies and Networks, China Information and Communication Technologies Group Corporation (CICT), Wuhan 430074, China
Up to now, the light coupling schemes of germanium-on-silicon photodetectors (Ge-on-Si PDs) could be divided into three main categories: (1) vertical (or normal-incidence) illumination, which can be from the top or back of the wafer/chip, and waveguide-integrated coupling including (2) butt coupling and (3) evanescent coupling. In evanescent coupling the input waveguide can be positioned on top, at the bottom, or lateral to the absorber. Here, to the best of our knowledge, we propose the first concept of Ge-on-Si PD with double lateral silicon nitride (Si3N4) waveguides, which can serve as a novel waveguide-integrated coupling configuration: double lateral coupling. The Ge-on-Si PD with double lateral Si3N4 waveguides features uniform optical field distribution in the Ge region, which is very beneficial to improving the operation speed for high input power. The proposed Ge-on-Si PD is comprehensively characterized by static and dynamic measurements. The typical internal responsivity is evaluated to be 0.52 A/W at an input power of 25 mW. The equivalent circuit model and theoretical 3 dB opto-electrical (OE) bandwidth investigation of Ge-on-Si PD with lateral coupling are implemented. Based on the small-signal (S21) radio-frequency measurements, under 4 mA photocurrent, a 60 GHz bandwidth operating at -3 V bias voltage is demonstrated. When the photocurrent is up to 12 mA, the 3 dB OE bandwidth still has 36 GHz. With 1 mA photocurrent, the 70, 80, 90, and 100 Gbit/s non-return-to-zero (NRZ) and 100, 120, 140, and 150 Gbit/s four-level pulse amplitude modulation clear openings of eye diagrams are experimentally obtained without utilizing any offline digital signal processing at the receiver side. In order to verify the high-power handling performance in high-speed data transmission, we investigate the eye diagram variations with the increase of photocurrents. The clear open electrical eye diagrams of 60 Gbit/s NRZ under 20 mA photocurrent are also obtained. Overall, the proposed lateral Si3N4 waveguide structure is flexibly extendable to a light coupling configuration of PDs, which makes it very attractive for developing high-performance silicon photonic integrated circuits in the future.
Photonics Research
2021, 9(5): 05000749

关于本站 Cookie 的使用提示

中国光学期刊网使用基于 cookie 的技术来更好地为您提供各项服务,点击此处了解我们的隐私策略。 如您需继续使用本网站,请您授权我们使用本地 cookie 来保存部分信息。
全站搜索
您最值得信赖的光电行业旗舰网络服务平台!