The Invention Journey of a Silicon Photonics Pioneer

TAOYUAN, Taiwan - Feb. 19, 2024 - PRLog -- For the silicon photonics research and development, Dr. Hung-Chih Lu, who is dedicated to cross-disciplinary public welfare creation, recalled his invention journey in the field of silicon photonics when he was young. He started developing silicon photonics in 1999, which was completely accidental, to be honest, it was a last resort. Intel and IBM did not start developing silicon photonics until after 2001.

Dr. Hung-Chih Lu said that he was originally doing photonic devices, but at that time Taiwan did not have a mature photonic device silica chip process, and they were still in development. Therefore, he thought of the mature silicon manufacturing process at that time, although the line width was a bit small for photons, but it could barely be used. Commercial silicon photonics was invented by Dr. Lu for this reason.

His idea at that time was to combine electronic computing and photonic transmission, combining the strengths of both, to solve the high-frequency limitation caused by the chip-to-pin bonding, and to replace the traditional wiring with the photonic transmission between chips. The core component is the patent US8406579 he invented, as shown in Figure 1, which can simultaneously realize wavelength division multiplexing and optical modulation, greatly reducing the size of photonic devices, and better matching with electronic devices.

https://drive.google.com/file/d/1qFdWXbiJG0b47_TeUDrHA1fFqvH6-d_j/view

Dr. Hung-Chih Lu believes that the strong necessity of silicon photonics will only emerge when there is a need for high-speed lateral communication between multiple super chips, or high-speed networking between super chips and optical fiber networks. As shown in Figure 2, this figure is a silicon photonics super chip created by Dr. Hung-Chih Lu using digital twin technology. In order to better demonstrate, he also quoted the die shots of Intel CPU and nVidia GPU to show the conversion and transmission between electronic signals and photonic signals.

https://drive.google.com/file/d/18NNCrekzpdozGugytm8-r8LnGGaysENw/view

Two different wavelength DC light sources are used as the photonic carriers of the transmission signals of the CPU and GPU respectively. After coupling into the waveguide optical path, the core component of US8406579 can simultaneously convert the electronic signals of the CPU and GPU into photonic signals, and then wavelength division multiplex them together, and transmit them out by the same optical fiber. This is the uplink, and the downlink is similar, changing the optical modulator to an optical detector, thereby converting the returned photonic signal back to an electronic signal.