Photonics Integrated with CMOS Under HELIOS Project

Europe is strongly positioned to design and manufacture silicon photonic devices, now that HELIOS, a four-year project to integrate photonics with electronics, has ended successfully, CEA-Leti announced Tuesday.

Silicon photonics is seen as key to developing future optical interconnects in microelectronic circuits, as engineers reach the technical limits of current integrated circuit technology. It is also essential to developing optical telecommunications, especially because of the cost advantages of integrating photonic and electronic functions on the same chip. CMOS photonics may lead to low-cost solutions for a range of other applications such as optical signal processing, optical sensing and biological applications.

The €8.5 million European Commission funded, 20-member HELIOS (pHotonics ELectronics functional Integration on CMOS) project, launched in 2008 and coordinated by French research and technology organization CEA-Leti, focused on developing essential "building blocks" for integrating a photonic layer with a CMOS circuit using standard microelectronics fabrication processes, such as WDM sources by III-V/Si heterogeneous integration, fast modulators and detectors, passive circuits and packaging.

Photonic layer bonded on the top of CMOS circuitry. Courtesy of the HELIOS project.

Establishing those building blocks led to results that exceeded the original specifications, officials said, such as a 10-Gb/s modulator integrated with an electronic BiCMOS driver, a 16 × 10 Gb/s transceiver for WDM-PON applications, a photonic QAM-10 Gb/s wireless transmission system and a mixed analog-and-digital transceiver module for multifunction antennas. (See: HELIOS Shows Off Laser Silicon Progress)

"Even if it has been challenging to assemble these buildings blocks to fabricate demonstrators, as the technology was more complex, advanced transceivers have been obtained," the members wrote in the project's final report. "Three different ways of integrating the photonic devices with electronic devices on a wafer-to-wafer basis were pushed with some success. With the work on innovative devices, the amorphous silicon modulator exhibited performances far beyond the original expectations.

"Even if lasing with Si nanocrystals has not been achieved, guided electroluminescence from slot waveguides and micro-ring resonators has been observed. CMOS-compatible 2.5 D III-V/Si VCSELs were highly efficient optically pumped, and lasing with electrical pumping will soon be demonstrated. Moreover, experimental demonstration of optical coupling of these VCSEL with silicon microguides has been achieved," the final report said.

"The technology road map of silicon photonics becomes clearer now," said Thomas Skordas, head of the EC's photonics unit. "Europe will have to move fast to become competitive in this new field. Strategies for the industrialization of silicon photonics are currently being discussed in the context of Horizon 2020, the EU's new framework program for research and innovation for 2014-2020."

"It is strategically important for Europe to maintain photonic chip design and chip-integrating functions to compete with other countries and to encourage innovation by European microelectronics companies," said Leti CEO Laurent Malier. "HELIOS's success in creating the essential building blocks for integrating photonics with CMOS circuits and making the process available to a variety of users underscores the key role that broad European technological cooperation plays in a very competitive global business environment."

The project led to more than 170 publications and communications in peer-reviewed journals and international conferences.

For more information, visit: www.helios-project.eu