Low-cost all-silicon optical modulator

optical modulator

Electronic-Photonic Convergence for Silicon Photonics Transmitters Beyond 100Gbit/s On-Off Keying

Technology: TSMC 28nm HPC & CORNERSTONE Si-Photonics 220nm Active

Dr Ke Li, Prof. David Thomson, Prof. Graham Reed

Combining photonics and electronics into a single integrated system


The optical modulator is the critical component in systems serving modern information and communication technologies, not only in traditional data communication links but also in microwave photonics or chip-scale computing networks.


In contrast to previous work in the field where electronic–photonic integration was mostly limited to the physical coupling approach between photonic and electronic devices, we have introduced a new design philosophy, where photonics and electronics must be considered as a single integrated system, in order to tackle the demanding technical challenges of this field.

Demonstrating the world-wide first design


The silicon modulator was fabricated through Southampton’s CORNERSTONE research fabrication foundry service (available from EUROPRACTICE), and integrated with a TSMC28nm CMOS drivers.


By designing the silicon photonics modulator and CMOS driver amplifier as a single integrated system, we have demonstrated the world-wide first all-silicon optical transmitter at 100GBaud/s and beyond, without the use of digital signal processing to recover the signal.

Reaching a low-cost all-silicon solution


This work demonstrates great potential for a low power, low-cost, all-silicon solution, without the need to dramatically complicate fabrication processes by bringing in new materials that are not necessarily CMOS compatible.



Ke Li, Shenghao Liu, David J. Thomson, Weiwei Zhang, Xingzhao Yan, Fanfan Meng, Callum G. Littlejohns, Han Du, Mehdi Banakar, Martin Ebert, Wei Cao, Dehn Tran, Bigeng Chen, Abdul Shakoor, Periklis Petropoulos, and Graham T. Reed, “Electronic–photonic convergence for silicon photonics transmitters beyond 100 Gbps on–off keying,” Optica 7, 1514-1516 (2020)

Microscope view of the packaged silicon photonics transmitter.