IRT Nanoelec Project integrates laser directly on silicon with a modulator

March 21, 2016 // By Graham Prophet
A III-V semiconductor/silicon laser integrated with a silicon Mach Zehnder modulator and built using wafer-towafer bonding of the different semiconductor substrates, has been demonstrated achieving 25 Gbps transmission over 10 km of single-mode fibre

IRT Nanoelec (Grenoble, France), an R&D consortium focused on information and communication technologies (ICT) using micro- and nanoelectronics, has announced co-integration of a III-V/silicon laser and silicon Mach Zehnder modulator demonstrating 25 Gbps transmission on a single channel. This transmission rate usually is achieved using an external source, over a 10 km single-mode fibre.


To achieve these recent results, silicon photonics circuits integrating the modulator were processed first on a 200mm SOI wafer, although 300mm wafers also could be used in the near future. Then, a two-inch wafer of III-V material was directly bonded on the wafer. In the third step, the hybrid wafer was processed using conventional semiconductor and/or MEMS process steps to produce an integrated modulator-and-laser transmitter.


Current interconnect technologies, which use micro-optics integration to assemble a discrete laser and a silicon photonic circuit, are believed to be reaching their limits and new, different solutions will have to be found to handle increasing traffic.


Integrating photonics capabilities on silicon ICs is replacing currently established technologies, increasing bandwidth, density and reliability, while dramatically reducing energy consumption. In the age of photonics-on-silicon, data transmission will be measured in terabits per second.


“Jointly obtained by STMicroelectronics and Leti in the frame of the IRT Nanoelec cooperation, these results, especially fabricating the laser directly on silicon, demonstrate IRT Nanoelec’s worldwide leadership in III/V-on-silicon integration to achieve high-data-rate fibre-optic modules,” said Stéphane Bernabé, project manager. “IRT Nanoelec and its partners on this project, Leti, STMicroelectronics, Samtec and Mentor Graphics, are paving the way to integrating this technology in next-generation transceivers for optical data links.”


IRT Nanoelec launched its silicon photonics program in 2012, with core members Mentor Graphics, STMicroelectronics and CNRS. The program brings together, under one roof, the expertise and equipment needed to address the entire photonics-on-silicon value chain.


Nanoelec Research Technological Institute (IRT), headed by CEA-Leti, conducts research and development in the field of information