With the development of big data, cloud computing, 5G, Internet of Things and other technologies, the information and communication industry is faced with the challenge of rapid growth in the volume of data services, and optoelectronic integration technology represented by silicon-based optoelectronics has become an important driving force for the future development of information and communication systems. Silicon modulators are one of the most important core devices in silicon-based optoelectronics. However, due to the slower carrier transport rate of silicon materials, the typical bandwidth of pure silicon modulators is 30-40 GHz, which is difficult to adapt to the future needs of ultra-100 Gbaud communication rate. This has been one of the bottlenecks in the rapid development of silicon-based optoelectronics.

Recently, the Center made a record-breaking breakthrough in ultra-high-speed, small-size pure silicon modulators, realizing the world's first pure silicon modulator with an electro-optical bandwidth of 110 GHz, which reaches the measurement limit of an experimental system with only a hundred micrometers in size and an optical bandwidth of 8 nm. OOK signal transmission at over 110Gbps rate for a single channel was successfully realized without using DSP. The silicon modulator also features world-record electro-optical bandwidth, ultra-small size, large optical bandwidth, and CMOS process compatibility, which meets the requirements of future Tbit-level optoelectronic integration for ultra-high speed, ultra-high integration density, high thermal stability, and wafer-level production. It will play an important role in data centers and high-speed optical communications.

(a) Electro-optical bandwidth 110 GHz (b) Optical bandwidth 8 nm (c) 100 Gbps OOK eye diagram (d) 112 Gbps OOK eye diagram

The results were presented as a PDP (Post-deadline paper accepted after the cutoff date) paper at the OFC Conference ("Optical Fiber Communication Conference") in San Diego, USA, in March 2022, under the title "Ultra-compact silicon modulator with 110 GHz bandwidth". Han Changhao, a PhD student of the Center, was the first author of the paper, Prof. Wang Xingjun was the corresponding author, and Jin Ming, Tao Yuansheng, Shen Bitao, and Shu Haowen, a postdoctoral student of the Center and a postdoctoral fellow of the Boxin Program, were involved in the related research work. We also thank Associate Professor Li Yanping of National Heavy Laboratory and Lingyun for their help in high-frequency testing. OFC conference is the top international conference in the field of optical communication with the largest scale and influence in the world. PDP papers are aimed at releasing the latest technological advances and record-breaking results in the field of optical communication, which represent the current highest technological level in the industry. In the history of the conference for more than 40 years, more than a thousand PDP papers have been published, and only a dozen papers have been published by research institutions in mainland China as the first unit, and only 24 papers have been published globally in the current OFC PDP.