The First Year of Photon Computer

Today, Xizhi Technology, a photonics computing hardware development company derived from MIT, announced that it has recently completed a $ 26 million Series round of financing. This round of financing was led by Jingwei China and China Gold Capital's Zhongjin Silicon Valley Fund. Xiangfeng Investment, Zhongke Chuangxing, China Merchants Venture Capital and other follow-up investments. Old shareholders Baidu Venture Capital and Fengrui Capital continued to increase.

Following the US $ 10.7 million seed round of financing in 2018, the company has completed preparations for refining talent reserves, improving design processes, and finalizing the supply chain. This round of financing raised Xizhi Technology's cumulative funding to 36.7 million US dollars, making it the world's highest-funded photon computing startup. And this round of financing also allows the company to maintain sufficient ammunition and accelerate the progress of productization. Next, the company will continue to invest in the development of the first product for the data center, and explore the commercial landing in some subdivided scenarios.

Photon chip

In recent years, in terms of how to provide more powerful computing power for machine intelligence, the academic community and the industry have been considering the next wave of development, photon computing is one of the potential options. The use of silicon photons for data transmission and matrix multiplication operations has promising prospects in terms of power consumption reduction and increase speed and it is likely to bring the largest opportunity for photon computing in history. Applied in a cloud computing environment, it can accelerate the training and inference of deep learning, and edge devices can also benefit from this technology, such as drones and sensors that are more sensitive to power consumption.

Dr. Shen Yichen, co-founder and CEO of Xizhi Technology, said: "In the past two years, photonic computing has received considerable attention around the world. It is no longer a scientific research project, but a productive technology, and there are many entrepreneurs. Companies and large companies have entered the market one after another. "One strong proof is that the first prototype board of Xizhi Technology has been faster than traditional electronic computing chips in performing tasks such as linear computing, and there are still considerable Large room for improvement. It can be said that as the first company in the field of photonic computing, Xizhi Technology has been running at the forefront. 

From the publication of an an important paper in Nature-Photonics by Dr. Shen Yichen and his team at the Massachusetts Institute of Technology in 2017, the new starting point of integrated photon computing was presented to the world, and the first product prototype was launched in early 2019 By 2020, the supporting algorithm will show the possibility of more application scenarios of the combination of soft and hard photon computing." Using Light to Challenge the" Top 7 Math Problems in the World ", MIT Team Reaffirms Optical Computing Potential ), and successfully attracted customers at home and abroad such as Google, FaceBook, AWS, BAT level contact, as the first company in the field of photonics computing, Xizhi Technology successfully succeeded in quickly cutting off the original cutting-edge computing technology in less than 3 years.

This young start-up company was also selected as MIT Technology Review 50 Smartest Companies in 2019 with Alibaba Cloud, Baidu, and Huawei. These achievements demonstrate the greater development potential of Xizhi Technology in the future. At present, Xizhi Technology has nearly 50 employees. It has developed its own multinational multi-disciplinary team in Boston, USA, and Shanghai, China. They all have fully functional optical laboratories. The team members include MIT, Columbia University, Georgia Institute of Technology. , Peking University, University of California, Berkeley and other outstanding graduates, as well as industry celebrities from Google, Microsoft, Intel, NVIDIA, AMD, ADI and other companies.

An innovative study to "restart" photon computing

Although Xizhi Technology is a young company, its focus on photon computing is actually an ancient technology field. As a technology that is completely different from electronic computing, photon computing uses photons as the information processing carrier, relies on optical hardware instead of electronic hardware, and uses optical computing instead of electrical computing. Appropriate application scenarios, and limited to traditional separate photonic devices, have the disadvantages of single light field control means and large photon design volume. Therefore, photon computing has always stayed in the laboratory stage. In recent years, electronic computing has become increasingly subject to Moore ’s Law, which has caused some people to turn their attention from “electricity” to “light” with faster speed and lower energy consumption.

On the one hand, driven by the field of optical communications, silicon-based optoelectronic technology has experienced very significant development in the past decade. To briefly explain the silicon-based photonics technology, it is to etch micro-level optical components on a traditional CMOS chip, which functions like mirrors, prisms, and displays in spatial optics. This technology greatly improves the integration of optical components. Photonic chips can use the current mature semiconductor process technology. Existing photonic chips only need 45-90 nm process to achieve the desired performance.

On the other hand, the popularity of deep learning systems based on artificial neural network algorithms, intensive matrix multiplication and data transmission are the most time-consuming and power-consuming artificial intelligence algorithms. However, photonic chips can be used to perform the two most important steps in all calculations, and have unique advantages: they can greatly reduce latency and energy consumption and increase bandwidth in on-chip data transmission and matrix operations. Therefore, the concept of photonic chip came into being.

The purpose of the establishment of Xizhi Technology is to cut into acceleration from the new angle of photonic chip. "For the industry, this may open a whole new direction and its development speed is much higher than that of electronic computing." Shen Yichen said. In 2016, when Shen Yichen was still a postdoctoral fellow at MIT, his research team built the first photon computing system. The result was published as a cover article in the top journal Nature-Photonics in 2017. It has double innovations in hardware and algorithms: In hardware, the optical interferometer as a basic matrix operation unit effectively replaces the traditional electronic transistor; In terms of algorithms, the team has developed a series of algorithms that effectively reduce the amount of deep learning calculations without sacrificing performance and are suitable for photonic chips.

At the time, David Miller, a well-known international optical scientist and a tenured professor at Stanford University, had written an article in Nature to evaluate the research results of Shen Yichen ’s team of photonic chips. He said, "This series of research results has greatly promoted the integration of photons in the future. Replace the development of traditional electronic computing chips. "

Xizhi Technology is also taking this as a starting point, and successfully released the world's first photonic chip prototype board in April 2019, which verified the ground breaking idea at the time. The system is integrated into conventional size boards. The team realized the improvement of computing efficiency, the maturity of the software environment and the degree of integration in about 2 years. This is a significant step for photonic computing to move from the laboratory to the market.

This prototype product successfully runs Google TensorFlow's own convolutional neural network model to process the MNIST data set. This is a benchmark machine learning model that uses computer vision to recognize handwritten digits and is also one of the most famous benchmark data sets in machine learning. In the test, more than 95% of the operation of the entire model was processed on the photonic chip. The test results show that the accuracy of the photonic chip processing is close to that of the electronic chip (more than 97%). In addition, the time taken by the photonic chip to complete the matrix multiplication is the most Within 1/100 of advanced electronic chips.

For this entrepreneurial team, this step also gave them more confidence to move forward with photon computing. As Shen Yichen replied to why entrepreneurship said: "The original intention of implementing photon computing cannot be achieved in the laboratory. It can only be achieved through the industrialization path of entrepreneurship. I have no choice. Now is the best time . "

Open up the boundaries of photon computing

The new computing technology developed in recent years is not just photon computing. The increasing demand for computing caused by AI has driven the market to launch more suitable new architectures for specific computing, such as neural network chip (NPU), quantum computing (Quantum Computing), etc., also rejuvenating. However, in terms of being able to continue the existing mature semiconductor process technology, the advantages of photonic chips are more obvious.

Shen Yichen said that Xizhi Technology plans to continue to develop through continuous regular filming in the future. It is expected that the company's first commercial product will face the data center and has also begun to cooperate with some domestic and foreign customers interested in the company's initial system. Another important point of the competition is that the new computing technology must be able to prove its own practical application value. Just as many large companies betting on quantum computing are "fighting" quantum superiority, photon computing also needs to answer this proposition. Therefore, on the basis of inheriting the existing mature semiconductor technology, Xizhi Technology is also continuously expanding the new territory of photonic computing applications. Until a new algorithm this year, they extended the boundaries to the "territory" of quantum computing, the efficiency of photon optimization for some complex problems is much higher than the existing quantum solutions that have been implemented.

Specifically, in January 2020, Shen Yichen et al. Invented a new Ising algorithm in a study published in Nature-Communications, which was specifically used to explore NP-complete problems based on photonic hardware. The efficiency of photon optimization for solving complex problems is much higher than that of existing quantum solutions. The better ability of photon to solve the Ising problem, from biological research to drug discovery to route optimization, has room for optimization problems encountered in a large number of scientific engineering. In the future, it may help biotechnology, Travel and other different industries. It is worth mentioning that this new photonic algorithm is based on the previous photonic chip prototype board of Xizhi Technology. Shen Yichen said: "Our next chip will completely subvert the existing similar electronic products in performance." Based on the characteristics of the fast photonic chip, low loss, high computing power and low cost, many deep learning scenarios facing performance bottlenecks will be the direction of this product. Covering hardware to algorithms, Xizhi Technology will devote itself to the layout and creation of a complete photonic computing system including chip design, core algorithms, and transmission in the next 2-3 years.

As we all know, chips are the most critical technology in various intelligent systems. The prosperity of the global chip industry in the past half-century has proved this, but China still needs to prove more: In the era of computing, which is completely dominated by electronics, China has already Falling distance and the new computing technology innovation is driven by large-scale application. Now, the entire electronic chip industry is constantly challenging the limits of semiconductor process technology to meet higher and higher computing performance requirements, but the price paid is also getting closer to the limit. Photonic chips are developing as potential technologies to meet this challenge. In this field, there is no market leader for the time being. Judging from the announced product progress, as the world's first photonic  chip company, Xizhi Technology will still be one of the most noteworthy companies-especially for China today, such technological innovation power is even more needed.

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