According to information published on Peking University's official website, Professor Wang Xingjun's research team at Peking University has achieved a major breakthrough in the fields of photonic integrated chips and micro-series after three years of research.
It is reported that Professor Wang Xingjun's research group and Professor John E. Bowers' research group at the University of California, Santa Barbara published an article entitled "Microcomb-driven silicon photonic systems" online in the journal Nature, reporting for the first time in the world a novel silicon-based optoelectronic on-chip integrated system driven by an integrated microcavity optical comb. This demonstrates that the research team has finally overcome this global challenge after three years of collaborative research.
(Screenshot of the paper)
According to Peking University News Network, Wang Xingjun's research team provided the necessary light source brain for silicon-based optoelectronic integrated chips by directly pumping integrated microcavity optical frequency combs with semiconductor lasers. Combined with mature and reliable industrial integration solutions for silicon-based optoelectronic integration technology, they achieved efficient parallelization of large-scale integrated systems.
This highly integrated system enables terabit-rate microcommunication and sub-GHz microwave photonic signal processing. A novel architecture for high-density, multidimensional multiplexing microcommunication and microprocessor chip-level integrated systems is proposed, pioneering the development of the next-generation multidimensional silicon photonic integrated microsystem sub-discipline. The research results are expected to be directly applied to data centers, 5/6G communications, autonomous driving, optical computing, and other fields, providing a new research paradigm and development direction for next-generation on-chip optoelectronic information systems.
The Current State and Future of Photonic Integrated Chips
As is well known, the performance of traditional chips mainly depends on the number of transistors integrated into the chip. If the individual transistors are small, then the number of transistors integrated into the chip is large, so the chip's computing power is relatively strong, and vice versa.
With the advancement of Moore's Law, traditional chips are increasingly challenged by the limited number of transistors, leading to the emergence of the new concept of photonic integrated chips. Photonic integrated chips, in essence, use higher-frequency light waves as the information carrier. Compared to electronic integrated circuits or electrical interconnect technologies, photonic integrated circuits and optical interconnects exhibit lower transmission loss, wider transmission bandwidth, smaller time delay, and stronger resistance to electromagnetic interference.
Furthermore, optical interconnects can increase the communication capacity within the transmission medium by using various multiplexing methods (such as wavelength division multiplexing (WDM) and mode division multiplexing (MDM)). Therefore, on-chip optical interconnects based on integrated optical paths are considered a highly promising technology to overcome the bottleneck problems caused by electronic transmission.
However, current photonic integrated chips still suffer from problems such as large device size, low efficiency, and limited functionality. This is due to the limitations of traditional optical waveguides in terms of structure and materials. Various research groups have also conducted in-depth research and attempts to address these issues through various methods.
In 2016, an Israeli research team introduced additional phase by adding a groove structure inside the waveguide to compensate for the transmission phase difference between different modes, thus realizing an integrated mode converter.
In 2017, researchers at Columbia University in the United States achieved asymmetric propagation in silicon nitride waveguides using metasurfaces integrated with gradients.
In 2020, a research team at Pennsylvania State University in the United States realized on-chip integrated optical devices with out-of-plane beam deflection and focusing functions by fabricating silicon waveguides on metasurfaces. In the same year, research teams from Tsinghua University in China and MIT in the United States used metasurface waveguide platforms to realize the design of integrated optical devices such as multifunctional integrated waveguide couplers, wavelength and polarization demultiplexers, and on-chip vortex beam emitters.
In 2021, research teams from Peking University and Tsinghua University also reviewed the research progress of micro/nano-structured integrated optical chips. Researchers from Huazhong University of Science and Technology and Zhejiang University also reported on research on on-chip reconfigurable mode converters and integrated silicon waveguide communication devices.
As can be seen, the development of photonic integration technology has achieved many important milestones in the past few years. With the failure of Moore's Law, electronic chips have encountered great challenges in terms of computing speed and power consumption. Photonic integrated chips, which use photons as the carrier of information, have the advantages of high-speed parallelism and low power consumption. Therefore, they are also considered by the public to be the most promising solution for high-speed, large-scale, and artificial intelligence computing and processing in the future.
For my country, this new type of quantum chip is very different from traditional chips in terms of manufacturing principle. This is because the quantum chip is mainly composed of a large number of quantum optical devices. Although the manufacturing of these devices requires the use of micro-nano processing technology, the requirements for processing equipment are not as strict as those for processing traditional chips. It can be completed with the help of low-end photolithography machines.
Secondly, compared with traditional chips, optical quantum chips have significant advantages. Using light as the carrier of information transmission, the stored information can be preserved for a longer period of time. Moreover, optical quantum chips are more resistant to external interference, have better compatibility, and more accurate control precision, making them the mainstream development direction for future chips.
Finally, the optical quantum chip, through a dynamically programmable structure, solves complex algorithmic problems such as fixed-point search by re-establishing the chip structure, demonstrating its enormous potential in realizing specific quantum computing applications. Once the optical quantum chip is successfully commercialized, research on process technologies such as 7nm and 5nm will lose its original significance, and China's chip manufacturing industry will enter a new milestone, breaking through the "bottleneck" dilemma in chip manufacturing.
