With the rapid development of technology, chip design is facing unprecedented challenges. Supported by the National Science and Technology Council’s (NSTC) "Key Emerging Chip Design R&D Program," a research team jointly formed by Associate Professor Pen-Jui Peng and Associate Professor Ping-Hsuan Hsieh from the Department of Electrical Engineering at National Tsing Hua University (NTHU), Associate Professor Yi-Chun Liu from NTHU's Institute of Electronics Engineering, and Dr. Ming-Wei Lin from the Taiwan Semiconductor Research Institute (TSRI) under the National Institutes of Applied Research (NIAR), has successfully developed a "4-level pulse amplitude modulation (PAM-4) transceiver." Combined with a co-packaged optics (CPO) module, this technology achieves a single-channel transmission rate of 100Gb/s. It is expected to replace traditional pluggable architectures for electro-optical conversion, meeting the growing demands for higher transmission rates and lower power consumption.

The PAM-4 transceiver enhances the signal's information by increasing the transmitted signal from the traditional two amplitude levels to four possible amplitude outputs, thereby effectively boosting the data transmission rate. However, accurately demodulating four different amplitude signals requires a relatively complex receiver circuit architecture. To address this, the team proposed an innovative PAM-4 receiver design. Its core concept is utilizing a low-resolution analog-to-digital converter (ADC) to achieve high-speed data sampling and demodulation.

This technology can effectively reduce overall power consumption. While major international high-speed chip companies rely on sub-7nm processes to achieve 100Gb/s transmission rates, this team's innovative architecture achieves comparable transceiver circuit performance using just a 28nm process. In addition to these structural improvements, the chip incorporates multiple self-calibration functions. These features can counteract errors caused by varying temperatures and mass production tolerances, thereby maintaining stable, consistent performance and enhancing the feasibility of actual mass production and commercial application.

Beyond the PAM-4 transceiver design, the team used the 100Gb/s electrical transceiver chip as a core, combined it with high-speed electro-optical conversion components on a silicon photonics interposer, and successfully developed a CPO module through heterogeneous integration packaging technology. This realizes the high-speed silicon photonics interposer development required for CPO modules. Silicon photonics technology utilizes silicon chips to fabricate optical components, allowing optical signals to be transmitted and processed directly on the chip. Compared to traditional pluggable optical modules, CPO modules enable a highly integrated design, shorten the system's transmission distance, effectively increase bandwidth, and reduce power consumption.

Compared to traditional electrical signals, optical signals offer higher bandwidth and lower power consumption, making them particularly suitable for high-speed data transmission and artificial intelligence (AI) data center applications. By integrating optical modulators, photodetectors, and electronic circuits, high-speed optoelectronic integrated chips and advanced packaging systems can be realized. The team has developed a silicon-based micro-ring modulator (MRM) capable of 100Gbps electro-optical conversion, and has successfully integrated high-speed photodetectors with a bandwidth exceeding 50GHz.

The key technologies developed by the team under this project have already secured 6 U.S. invention patents and 8 Taiwan invention patents. During the project's execution, multiple industry-academia collaboration projects were also generated. Moving forward, the team aims to further implement these technologies into industrial applications, driving Taiwan's continued development and leadership in related fields.

Media Contact：

Ming-Fei Lee

Assistant Researcher

Department of Engineering and Technologies

National Science and Technology Council

Tel: +886(2) 27377437

E-mail: mflee@nstc.gov.tw