imec and CST Global collaborate to extend silicon photonics

05 Mar 2020

Portfolio to be enhanced with hybrid integrated indium phosphide light sources.

SEM image of an InP DFB laser assembled on a Si photonics chip.

Nanoelectronics research hub imec, and CST Global, a UK-based producer of III-V compound semiconductors for photonics applications, have successfully integrated indium phosphide distributed feedback lasers from CST’s InP100 platform into imec’s integrated silicon photonics platform (iSiPP).

The partners say that interfaces for hybrid integration of InP DFB lasers and reflective semiconductor optical amplifiers will become available as part of imec’s silicon photonics prototyping services in the first half of 2021, following further optimization and qualification work, this year.

In this week’s announcement, they state, “This joint offering is expected to boost the adoption of silicon photonics in cost-sensitive applications, including optical interconnects, sensing, computing and beyond.”

Silicon photonics technology, which has made great progress over recent decades, is used extensively in a variety of applications – from fiber-optic communications to sensing. Technology platforms have evolved into mature vehicles and are available to industry and academia for prototyping, low-volume and higher-volume manufacturing.

Missing link

But a widely available, cost-effective solution to integrate light sources in SiPho chips has been missing, hampering the adoption of SiPho in cost-sensitive markets. Silicon itself does not emit light efficiently, so light sources made of III-V semiconductors, such as indium-phosphide or gallium-arsenide, are typically implemented as separately packaged components. Such external light sources typically suffer from higher coupling loss; a large physical form factor; and a substantial packaging cost.

The imec–CST Global collaboration, which started in 2019, has now resulted in the first successful assemblies of C-band (1530-1565nm) InP DFB lasers onto imec’s iSiPP platform. The InP lasers were “flip-chip” integrated onto the SiPho circuits through a die-to-die bonding process, aligning efficiently and coupling >5mW into the SiN waveguides on the SiPho chip.

Available soon: InP DFB laser assembled on a Si photonics chip.

Joris Van Campenhout, Program Director Optical I/O at imec, commented, “Our first passive laser assemblies have demonstrated excellent initial results. Throughout 2020, we will further optimize the precision and throughput of the laser assembly process; extend the functionality to include RSOA integration at 1310/1550nm wavelengths; and perform reliability qualification.

“We expect that the availability of these hybrid, integrated light sources will boost industrial uptake of SiPho devices in a variety of cost-sensitive markets. Early access through imec’s iSiPP200 prototyping services is anticipated by the first half of 2021."

Antonio Samarelli, Integration Manager at CST Global, commented, “The hybrid integration of InP light sources, such as DFBs and RSOAs, designed and fabricated on CST’s InP100 manufacturing platform and combined with the iSiPP platform, allows the creation of powerful photonic integrated circuits for advanced components with improved performance and lower cost.

“We will continue to work closely with imec to extend the functionality and capabilities of the InP100 platform to meet the InP light source requirements of novel, advanced PICs for high volume commercial applications.”