The main objectives of DIMENSION are:
- Establish a silicon platform monolithically combining BiCMOS electronics with silicon photonics and III-V photonics
- Fully CMOS compatibility
- Integrated devices, with CMOS, photonic and III-V functionality at the cost of silicon volume fabrication
The DIMENSION monolithic III-V on silicon integration concept is based on the following aspects:
- Bonding or growth of an ultra-thin (<500 nm) III-V quantum well stack on the front-end of line BiCMOS structure, as shown in the picture below.
- Embedding the III-V structure in the back-end of line stack to provide short and fast electrical interconnects to the electrical (Bi)CMOS devices.
- Efficient optical coupling between the silicon and III-V layer based on adiabatic mode conversion.
- Laser feedback and passive optical structures are realised in the silicon layer for minimum processing requirements on the III-V structure.
This (Bi)CMOS/silicon photonics/III-V photonics silicon platform enables breakthrough advancements at device and system-level:
- Extended design flexibility and scalability of electro-optical structures by integration of active III-V structures at any position on the wafer
- Improved overlap of the optical mode with the active III-V quantum well region providing lower threshold lasing
- Enhanced functionality and device control at chip-level enabling laser wavelength and power stabilization, direct laser modulation and many other innovations
- Simplified and ultra-dense electro-optical packaging solutions.
- Cost savings by up to one order of magnitude by mitigating the application of discrete lasers and overcoming a substantial fraction of the packaging and assembly cost.
- Power savings of more than 70% by enabling fast direct modulation of an on-chip silicon laser and overcoming laser to chip optical coupling losses.
To direct the development of the DIMENSION electro-optical platform and to ensure the realisation of system-relevant devices special attention will be paid to:
- The verification of system requirements and a related definition of optical link specifications
The prospects of the technology platform will be validated in three demonstrators as described below including the target specifications:
- A short-reach transmitter for intra-datacenter operation addressing the 400 GbE-LR8 (IEEE 802.3bs) standard making use of an array of directly modulated lasers, pulse-amplitude-modulation (PAM4) techniques and 8 wavelength channels modulated at 25 GBaud in the telecom O-band.
- A medium-reach transmitter for inter-datacenter applications beyond the 400 GbELR8 (IEEE 802.3bs) standard by providing a tuneable coherent transmitter for inter-datacenter and metro applications for link lengths in excess of 10 km using a tuneable narrow linewidth laser combined with a silicon photonics modulator integrated on the same chip.
- A novel directly-modulated III-V laser directly grown on silicon photonics, operated at 25 Gb/s in the telecom O-band demonstrating the significant cost-saving potential of the technologies pursued in DIMENSION.
Based on the technology findings and results the project will perform:
- A techno-economic and performance evaluation of the DIMENSION technology and solutions.