Silicon photonics

A closeup photo of an electronic circuit board.

Silicon photonics is the new microelectronics. Photonic integrated circuits and chips can revolutionise numerous applications from optical communication and quantum computing to medical imaging, gas sensing and autonomous vehicles.

Key facts

3 µm thick Si waveguides for single-mode circuits with low losses and small footprint.

Ultra-broadband operation from 1.2 to over 4 µm wavelength.

Polarisation independent components and circuits. 

Silicon photonics (SiPh) will be the photonic or optical equivalent of microelectronics in near future. Invention of integrated electronic circuits, or ICs, in 1960s replaced discrete electronic transistors and electron tubes, revolutionising modern-day electronics.  

Photonic integrated circuits (PICs), based on SiPh, are also going to replace bulky and expensive photonic modules having individual components such as lasers, wavelength filters and photodetectors and condense them into one chip. These PICs can be used in applications that range from intelligent multi-gas sensors, LIDARs and medical imaging devices to energy-efficient optical links for data-centers and quantum computers. Maybe someday even refrigerators will have a small PIC chip and not just IC chips, like they do today!

Unique silicon photonics with micron-scale waveguides

At VTT, we pattern optical waveguides into a 3 µm thick silicon-on-insulator (SOI) layer. Light remains extremely well-confined inside the micron-scale Si waveguides, which leads to a unique combination of low propagation losses (~0.1 dB/cm), small polarisation dependency, dense integration and relaxed fabrication tolerances. By combining rib and strip-shaped waveguides it is possible to achieve single-mode (SM) operation over an ultra-wide wavelength range (like 1.2–3 µm) while pushing bend radii down to a few micrometers. Our latest highlights include 40 GHz photodetectors and 1xN wavelength multiplexers with <1 dB loss, while our future visions include >100 GHz modulators and on-chip optical circulators.

From research and prototyping to volume production

VTT uses the Micronova clean room facility for processing PICs on commercial SOI wafers (150 mm / 6" diameter). For customers around the world we offer the low-cost option to join our multi-project wafer (MPW) runs, as well as dedicated processing runs and strategic partnerships for product development. Those who want to commercialise their Si photonic products can obtain contract manufacturing services from VTT Memsfab Ltd (in the same facility).  

We can do the design for you or you can do your own design using our process design kits (PDKs) that are supported by commercial design tools. VTT also offers packaging and testing services for the fabricated silicon photonic chips. You can also benefit from our extensive network of R&D partners around the world for subcontracting, hybrid integration of III-V optoelectronics, funding opportunities etc.

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