EU project makes progress on photonic integrated circuits
Advances in silicon photonic integrated circuits (PICs) have been reported by the EU project SEQUOIA (energy efficient Silicon Emitter using heterogeneous integration of III-V QUantum dOt and quantum dash materIAls).
Started in 2013, the SEQUOIA project has been looking into developing hybrid III-V lasers with better thermal stability, higher modulation bandwidth and the possibility of generating a flat wavelength-division-multiplexing comb.
Using the hybrid integration of nano-structured materials on silicon, the idea is that optical filters can be directly integrated with hybrid quantum dot/quantum dash/silicon lasers to create chirp-managed lasers, which have an enhanced modulation bandwidth and extinction ratio compared to directly modulated lasers. As an illustration of the technology, the aim is to develop transmitters with a total capacity of 400Gbps (16x25Gbps).
During the first period of the project, the quality of Qdot/Qdash materials has been significantly improved and the University of Kassel has recently demonstrated Qdot lasers with a record 34Gbps bit rate in direct modulation. In parallel, Qdot wafers have been successfully bonded onto silicon wafers.
The two types of PIC final demonstrators have also been designed: chirp-managed lasers (CMLs) directly modulated at 25Gbps and comb laser integrated with cascaded ring resonator modulators. These PICs, providing a total capacity of 400Gbps through the use of 16 WDM channels, will offer better performance at reduced cost and enhanced functionality through the use of new materials and novel integration processes.
The consortium is led by III-V Lab, a research lab with expertise in InP-based photonics and hybrid integration of III-V on silicon. Two German partners, Dortmund based company Innolume and the University of Kassel, have a track record in Qdot materials and on III-V optoelectronics. Other partners are CEA-LETI; DTU Fotonik in Denmark; and Foton Laboratory at University of Rennes in France.
