Researchers at Intel Labs has developed a key element of photonics that could boost the performance of chiplets in high performance data centre chips.
The researchers have demonstrated an eight-wavelength distributed feedback (DFB) laser array that is fully integrated on a silicon wafer and delivers high output power uniformity of +/- 0.25dB and wavelength spacing uniformity of ±6.5% that exceed industry specifications.
The laser array is built on Intel’s 300mm silicon photonics manufacturing process to pave the way for high-volume manufacturing and broad deployment. Intel is in the process of buying Tower Semiconductor for its photonics manufacturing expertise, and Europe is setting up a dedicated supply chain for the technology in the region. X-fab is a key technology supplier for this.
- €1.1bn for a European photonics supply chain
- World’s first open silicon photonics platform with monolithic III-V lasers
- Deal creates largest European foundry capacity for integrated photonics
The hybrid silicon photonics platform is used to manufacture production optical transceivers in volume and the ability to build a laser array in the same process is a key step forward.
Intel used advanced lithography to define the waveguide gratings in silicon to split the wavelengths prior to the III-V wafer bonding process that adds the laser. This technique resulted in better wavelength uniformity compared to conventional semiconductor lasers manufactured in 3-inch or 4-inch III-V wafer fabs. In addition, due to the tight integration of the lasers, the array also maintains its channel spacing when the ambient temperature is changed.
This will boost the ability to co-package a multiwavelength optical source with optical compute interconnect for emerging network-intensive workloads including artificial intelligence (AI) and machine learning (ML).
By 2025, Gartner forecasts that silicon photonics will be used in more than 20% of all high-bandwidth data centre communications channels, up from less than 5% in 2020, and will represent a total available market of $2.6bn.
“This new research demonstrates that it’s possible to achieve well-matched output power with uniform and densely spaced wavelengths. Most importantly, this can be done using existing manufacturing and process controls in Intel’s fabs, thereby ensuring a clear path to volume production of the next-generation co-packaged optics and optical compute interconnect at scale,” said Haisheng Rong, senior principal engineer at Intel Labs.
Many aspects of the eight-wavelength integrated laser array technology are being implemented by Intel’s Silicon Photonics Products Division as part of a future optical compute interconnect chiplet product. This will provide multi-terabits per second interconnect between compute resources including CPUs, GPUs and memory.
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