Fudan Manufacturing World's First All-Silicon Laser: Promoting Full Silicon Laser Industry Development

A few days ago, Professor Wu Xiang, Professor Lu Ming and Associate Professor Zhang Shuyu of the School of Information Science and Engineering at Fudan University successfully developed the world's first all-silicon Laser. Unlike previous hybrid silicon-based lasers, this study ultimately produced lasers using silicon itself as a gain medium. This research is a major breakthrough made in the field of integrated silicon optoelectronics in the past 30 years.

Integrated silicon optoelectronics combines the essence of today's two pillar industries - microelectronics and optoelectronics. The silicon laser is the basic component of the integrated silicon optoelectronic chip and is the key to implementing integrated silicon optoelectronics. The integrated silicon photoelectron is expected to be widely used in many fields such as remote data communication, sensing, lighting, display, imaging, detection, and big data.

However, silicon itself has extremely weak light emission. How to treat silicon into a laser material with high gain has been a bottleneck. Since 2000, experiments have proved that silicon nanocrystalline materials can achieve optical amplification, this bottleneck has always limited the development of silicon lasers.

As early as 2005 when the all-silicon Raman laser was introduced, the news about "all-silicon lasers" had caused social concern. However, this is a laser produced by introducing an external laser into a silicon chip, and silicon itself does not serve as a light source. In the same year, hybrid silicon-based lasers were introduced. This laser is based on the existing silicon-based waveguide chip, and is directly bonded to a mature III-V semiconductor laser, so that the two components are combined into a hybrid silicon-based laser. Similarly, silicon itself is not a light source. Hybrid lasers have poor compatibility with existing silicon processes and can also cause lattice mismatch problems.

The silicon laser developed this time is different from the past, its luminescent material (gain medium) is silicon itself (silicon nanocrystalline material), the laser can be made on the silicon chip, so it is a true all-silicon laser.

The research team of Fudan University first learned and developed a high-density silicon nanocrystalline thin film preparation technology, which significantly improved the luminous intensity of the silicon nanocrystalline luminous layer; then, in order to overcome the conventional hydrogen passivation method can not fully saturate the dangling bond defects. One problem, they developed a new type of high-pressure, low-temperature hydrogen passivation method that makes the optical gain of the silicon nanocrystalline light-emitting layer reach the level of a typical III-V laser material at one stroke; on this basis, they designed and prepared the corresponding Distributed feedback (DFB) resonators eventually succeeded in obtaining optically pumped DFB type all-silicon lasers. This laser not only overcomes the problem of lattice mismatch and poor process compatibility that can occur during the growth of semiconductor materials. At the same time, as the second most abundant element of surface reserves, light gain materials made of silicon can also avoid rare elements such as Excessive dependence on gallium, indium, etc.

It is reported that in the future, the team will further develop and perfect electric pump technology and promote the industrial development of all-silicon lasers.