5 March 2012

CEA-Leti and III-V lab demo fully integrated silicon photonics transmitter

Micro/nanotechnology R&D center CEA-Leti of Grenoble, France and III-V Lab (a joint venture between Paris-based Alcatel-Lucent Bell Labs France, Thales Research and Technology, and CEA-Leti, which joined III-V Lab in March 2011 to contribute silicon integration capabilities) have demonstrated what is claimed to be the first tunable laser transmitter integrated on silicon, representing “a key milestone towards fully integrated transceivers”.

The transmitter incorporates a hybrid III-V/Si laser (fabricated by direct bonding) that exhibits 9nm wavelength tunability together with a silicon Mach-Zehnder modulator with a high extinction ratio (up to 10dB), leading to what is claimed to be excellent bit-error-rate performance at 10Gb/s. The results were obtained in the framework of the European-funded project HELIOS (pHotonics ELectronics functional Integration on CMOS), with the contributions of Ghent University-IMEC for the design of the laser and the UK’s University of Surrey for the design of the modulator.

CEA-Leti and III-V Lab have also demonstrated single-wavelength tunable lasers, with a threshold current of 21mA at 20°C, 45nm tuning range, and a side-mode suppression ratio larger than 40dB over the tuning range.

The results are being overviewed at this week’s Optical Fiber Communication conference (OFC 2012) in Los Angeles (4-8 March), where CEA-Leti is exhibiting in booth #718.

CEA-Leti and III-V Lab claim that the development represents a significant breakthrough in silicon photonics by integrating on the same chip complex devices such as a fully integrated transmitter working above 10Gb/s or a tunable single-wavelength laser.

Silicon photonics has the promise of bringing the large-scale manufacturing of CMOS silicon to photonic devices that are currently still expensive due to a lack of ubiquitous technology. A big obstacle to silicon photonics is the lack of optical sources on silicon. “We can overcome this problem by bonding III-V material - necessary for active light sources - onto a silicon wafer and then co-processing the two,” says Martin Zirngibl, Bell Labs Physical Technologies Research leader. “Traditional CMOS processing is still used in the process, while at the same time we now can integrate active light sources directly onto silicon,” he adds.

Based on the heterogeneous integration process developed by CEA-Leti and III-V Lab, III-V materials such as indium phosphide (InP) can be integrated onto silicon wafers. The fabrication process starts on 200mm silicon-on-insulator (SOI) wafers, where the silicon waveguides and modulators are fabricated on CEA-Leti’s 200mm CMOS pilot line.

“The ability to integrate a tunable laser, a modulator and passive waveguides on silicon paves the way for further developments on integrated transceivers that can address several application needs in metropolitan and access networks, servers, data centers, high-performance computers as well as optical interconnects at rack-level and board-level,” says Laurent Fulbert, photonics program manager at CEA-Leti France.

See related items:

France’s CEA-Leti joins III-V Lab

Tags: CEA-Leti III-V lab Silicon photonics transmitter HELIOS SOI

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