Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA)

CEA (Commissariat à l’Energie Atomique et aux Energies Alternatives) is a French Governmental Research Organisation (15000 employees) devoted to both fundamental and industrial Research & Development. Within CEA, CEA-LETI is one of the major European research centres for applied electronics. It is located in Grenoble where it operates 11000 m²-State-of-the-Art CMOS clean rooms, 200 and 300 mm wafer size, and the 200 mm MEMS microsystems platform, with equipment worth some 200 M€. Nearly 1,600 men and women are serving innovation and the transfer of technology in key domains, with ST microelectronics as the main industrial partner. CEA-LETI has sparked the creation of nearly thirty high-technology start-ups, including Soitec, world leader in the development/ production of Silicon on insulator wafers.

As a pioneer in Research & Development in Silicon Photonics (2002) CEA-Leti has developed strong expertise and know how in device design, integration and test, including Ge-on-Silicon photodetectors and heterogeneous III/V-on-Silicon lasers. Having achieved the development of world-record-output-power lasers, and 200mm-wafer-size processing, CEA is considered as a leading institute in the field.

Main tasks in PICTURE:

Within the PICTURE project, CEA will enhance its 200 mm silicon photonics platform by implementing a new III-V on Silicon hybrid bonding scheme using a thin oxide bonding layer to obtain optimized hybrid active devices such as hybrid III-V on Si lasers with improved power efficiency and thermal behaviour, very efficient and low power consumption III-V on Si hybrid capacitive modulators and photodiodes. CEA will develop multi-die bonding technology in order to use the expensive III-V material only where it is necessary for active devices and to use III-V epitaxial stacks based on QW or QD active layers separately optimized for the laser, the modulator and the photodetector. Importantly, CEA will develop the whole fabrication process of III-V on Si photonic integrated circuits on its 200 mm CMOS platform to demonstrate the industrial manufacturability. In addition CEA, will work on the design of efficient, low-voltage and low-power consumption hybrid III-V on Si modulators and perform characterization of all the passive and active building blocks up to 67 GHz operation on its Automatic Prober stations.

CEA has developed a 200 mm Silicon photonics platform including passive components such as waveguides, single polarization and polarization-splitting fiber couplers, multiplexers /demultiplexers and active components operating at 25 Gb/s such as Si modulators based on a PN junction in depletion and Ge photodetectors. CEA has developed an expertise in the design of all these components and in particular on the design of silicon modulators based on various junction types such as PN, PIN and capacitive junctions.

CEA has also successfully developed the integration of III-V lasers DBR and DFB lasers based on the direct bonding of III-V wafers on Silicon, and their integration with silicon modulators.

Dr. Karim Hassan, project board member for LETI of PICTURE  received his PhD degree in physics from the University of Burgundy, Dijon, France, in 2013 on the development of thermo-optical plasmonic routers for telecom applications in the framework of the FP7 project PLATON.  He joined CEA-Leti in 2014 where he works currently on silicon photonics as research fellow (H2020 COSMICC, ANR IRT-Nanoelec) and manager of the FP7 project SEQUOIA. His research interest includes the design, fabrication, and characterization of silicon photonics circuits, hybrid III-V on silicon laser sources, and topological optimization for nanophotonics. He has authored or coauthored more than 50 journal publications, conference papers and patents.

• The following projects are among those referring to silicon photonic integration carried out at LETI
• French ANR MICROS (2010-2014): In this project, CEA has developed the III-V on Si integration technology. One of the major achievements of this project was the joint demonstration with III-V Lab of a first generation hybrid III-V on silicon CW tunable laser over 45 nm at 1.55 µm for coherent transmission applications.
• FP7 FABULOUS (2012-2015): The objective of this project was to realise an integrated Optical Network Unit (ONU) transceiver for access network applications. CEA was involved in the design, technology and characterization of transceiver circuits including III-V on Si optical amplifiers.
• ANR ULTIMATE (2012-2015): The objective of this project was to demonstrate a 4x100 Gb/s transmitter based on silicon photonics for long-haul telecommunications at 1.55 µm. CEA has performed the optimization of Silicon modulators based on a PN junction in depletion to obtain the best compromise between high efficiency, low insertion losses and bandwidth compatible with operation at 25 Gbaud/s. The optimization of geometry and doping is based on an integrated simulation tool developed at CEA, combining optical, electrical and implant simulations. CEA was also responsible of the fabrication of the transmitter circuits including III-V on Si lasers.
• FP7 PLAT4M (2012-2017): The objective of this project is to build up a silicon photonics platforms in Europe. CEA is responsible of the development of a reproducible silicon photonics platform including passives and active components (Silicon modulators and Germanium photodetectors at 25 Gb/s).
• FP7 SEQUOIA (2013-2017): The objective of this project is to demonstrate hybrid quantum dot/quantum dash lasers on silicon and their integration in transmitter circuits for telecom and Datacom applications. CEA is in charge of the technological fabrications runs.
• H2020 COSMICC (2015-2018): The objective of this project is to demonstrate silicon photonics mid-board transceivers with an aggregated data rate beyond 1 Tb/s using high fiber throughput. CEA is coordinating the project and is in charge of the enhancement of its 200 mm R&D platform with an SiN additional waveguiding layer to build thermally insensitive MUX/DEMUX and adiabatic Si/SiN/Polymer couplers. CEA is also in charge of developing higher-efficiency silicon PN modulators based on slow-wave design.

CEA-Leti will make use of its infrastructures located in Grenoble. This includes state of the art CMOS processing with 11,000m² clean rooms, and 200mm (8inch) & 300mm (12inch)-wafer-processing lines. The infrastructure further includes two 300-mm-wafer probe-testers, equipped for electro optic characterizations of bare photonic dies (DC, ac up to 67 GHz), with thermal heating and cooling capabilities (see figures below).

© CEA-Leti/Ph Clean room environment

300mm probe tester with 67GHz VNA (modulator under test displayed on the screen)