LEUVEN, Belgium, July 9, 2018 — Today at its Imec Technology Forum USA in San Francisco, imec, the world-leading research and innovation hub in nano-electronics and digital technology, announced that it has demonstrated ultra-low power, high-bandwidth optical transceivers through hybrid integration of Silicon Photonics and FinFET CMOS technologies. With a dynamic power consumption of only 230fJ/bit and a footprintof just 0.025mm2, the 40Gb/s non-return-to-zero optical transceivers mark an important milestone in realizing ultra-dense, multi-Tb/s optical I/O solutions for next-generation high-performance computing applications.

The exponentially growing demand for I/O bandwidth in datacenter switches and high-performance computing nodes is driving the need for tight co-integration of optical interconnects with advanced CMOS logic, covering a wide range of interconnect distances (1m-500m+). In the presented work, a differential FinFET driver was co-designed with a Silicon Photonics ring modulator, and achieved 40Gb/s NRZ optical modulation at 154fJ/bit dynamic power consumption. The receiver included a FinFET trans-impedance amplifier (TIA) optimized for operation with a Ge waveguide photodiode, enabling 40Gb/s NRZ photodetection with an estimated sensitivity of -10dBm at 75fJ/bit power consumption. High-quality data transmission and reception was also demonstrated in a loop-back experiment at 1330nm wavelength over standard single mode fiber (SMF) with 2dB link margin. Finally, a 4x40Gb/s, 0.1mm2 wavelength-division multiplexing (WDM) transmitter with integrated thermal control was demonstrated, enabling bandwidth scaling beyond 100Gb/s per fiber.

“The demonstrated hybrid FinFET-Silicon Photonics platform integrates high-performance 14nm FinFET CMOS circuits with imec’s 300mm Silicon Photonics technology through dense, low-capacitance Cu micro-bumps. Careful co-design in this combined platform has enabled us to demonstrate 40Gb/s NRZ optical transceivers with extremely low power consumption and high bandwidth density,” says Joris Van Campenhout, director of the Optical I/O R&D program at imec. “Through design optimizations, we expect to further improve the single-channel data rates to 56Gb/s NRZ. Combined with wavelength-division multiplexing, these transceivers provide a scaling path to ultra-compact, multi-Tb/s optical interconnects, which are essential for next-generation high-performance systems.”

This work has been carried out as part of imec’s industrial affiliation R&D program on Optical I/O and was presented at the 2018 Symposia on VLSI Technology and Circuits (June 2018) in a “late news” paper. Imec’s 200mm and 300mm Silicon Photonics technologies are available for evaluation by companies and academia through imec’s prototyping service and the iSiPP50G multi-project wafer (MPW) service.

Source: imec