In a runup to the 2023 Optical Fiber Communication Conference (OFC) in San Diego from Mar. 5-9, OFC this January reported on how new coherent optical link architecture technology uses both photonic and electronic integrated circuits to help internet data centers achieve higher data rates while consuming less power.
In an important step toward meeting tremendous global demands for more bandwidth, OFC's statement cited how industry researchers are now reporting the first O-band optical link technology to accomplish more than 200 Gbps single wavelength transmission using an integrated transmitter and receiver based on photonic and electronic integrated circuits.
The researchers designed the link using a new analog coherent detection architecture that consumes just 1.5 W of power.
According to a press release, the research is a product of the US Department of Energy ARPA-E ENLITENED program, which aims to double data center energy efficiency through advanced optical networking technologies.
Aaron Maharry, Ph.D. from the University of California in Santa Barbara (UCSB) will present the new findings at this year's OFC Conference.
The work builds upon the research team’s previous demonstration of the first full O-band coherent link with integrated transmitters and receivers based on photonic and electronic integrated circuits.
Maharry commented:
“This is a major step towards next generation data center networks built on coherent optical links...These links will enable data centers to economically scale network throughput with lower energy consumption, leading to a better, more sustainable, and cheaper internet.”
Coherent links replace IMDD
The optical links used in the data centers that form the backbone of the internet often rely on a communication approach known as intensity modulation direct detection (IMDD). As noted by OFC, rising data rates have led to increasing interest in replacing IMDD links with more scalable coherent links.
However, the high-power consumption and cost of coherent links have prevented their widespread adoption.
To overcome these limitations, researchers from UCSB and Intel Corporation designed an analog coherent detection link architecture that removes the power-hungry digital signal processing functions that are required for longer-reach conventional coherent links.
Maharry explained:
“We have reimagined how next-generation optical links should work for short reaches. Instead of relying on the same advanced techniques used in undersea cable transmission, we designed and built chips that are optimized for shorter links and can offload digital signal processing functions efficiently into the analog domain. We have been excited to collaborate with Intel for this work, as their proven silicon photonic process with integrated optical gain is the ideal technology to realize this new architecture.”
Using the new link architecture, the researchers demonstrated 224 Gbps/λ dual polarization quadrature phase shift keying (DP-QPSK) transmission with 6.8 pJ/bit power consumption and a data transmission accuracy above the necessary 99.62% threshold.
According to the authors, incorporating photonic integrated circuits with integrated optical gain could create a link with a power consumption of less than 10 pJ/bit.
The researchers said future designs could also incorporate wavelength division multiplexing to create four or eight channels that would allow 800G or 1.6T transmission rates, respectively.
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