Consortium Integrates Laser on Silicon with Modulator
IRT Nanoelec, an R&D consortium focused on communication technologies using micro- and nanoelectronics, has announced the co-integration of a III-V/silicon laser and silicon Mach Zehnder modulator, using direct wafer bonding.
The team has demonstrated 25 Gbps transmission on a single channel, a rate usually achieved using an external source over a 10 km single-mode fibre.
Current interconnect technologies, which use micro-optics integration to assemble a discrete laser and a silicon photonic circuit, will soon reach their limits and new, different solutions will have to be found to handle increasing traffic, according to the researchers. Integrating photonics capabilities on silicon chips will vastly increase 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.
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.
"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 fiber-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."
