Labs Paper Highlights Breakthrough in Silicon Photonics Data Transmission

[Labs_Editorial]

To meet the processing requirements of tomorrow’s AI and high-performance computing applications, data needs to move faster.

Hewlett Packard Labs is working to solve this challenge two ways. Using silicon photonics, researchers have developed a mechanism to transmit signals between processors, memories, and among computing nodes at higher bandwidths without losing efficiency in the device’s performance. Now Labs has made advances on the other end of the equation – by receiving data more efficiently and at lower costs.

In a paper published on August 9 in Nature Photonics, researchers from the Large-Scale Integrated Photonics Lab are proposing a new way to convert optical signals to electrical signals using silicon photonics alone – without having to add more costly materials to help the signal along. Streamlining the production of photodiodes could help future designers improve the performance of circuits themselves and data centers overall.

“As an industry we’re collectively trying to find ways to make data flow more freely and enable systems to do more productive work,” said Hewlett Packard Labs research scientist Yiwei Peng, the lead author of the paper, “An 8×160 Gbps All-Silicon Avalanche Photodiode Chip.” “Helping optical signals make more seamless connections will help systems evolve so they can solve tomorrow’s problems.”

To significantly improve circuit performance, researchers throughout the industry are working on solutions that could raise optical interconnect rates from the current standard of 400 gigabits per second to upwards of 3.2 TB/sec.

The Labs team is proposing an all-silicon solution that uses an eight-channels double-microring resonator to amplify the optical signal. Using eight channels in parallel brings in light through a wider range of bandwidth, enabling the receiver to process signals at higher data rates.

The team has reported positive results. Peng said the “avalanche photodiodes” converted optical signals with a high degree of efficiency, a low degree of noise, and exceptional device uniformity. The team reached a high transmission data rate of 160 Gb/s per channel at 1310 nm while achieving ultra-low electrical channel-to-channel crosstalk of under -50 dB. While others have transmitted up to 1.28 TB/sec (eight channels, each at 160 Gb/sec) using conventional photonics, the Labs team believes it’s the first all-silicon solution able to transmit at these speeds.

“Our research shows that all-silicon optical receivers can compete with heterojunction-based receivers in terms of performance while also promising up to 40% savings in overall chip costs,” Peng said. “It’s moving us closer and closer to the performance goals we all seek to achieve.”

The paper was written by Yiwei Peng, Yuan Yuan, Wayne V. Sorin, Stanley Cheung, Zhihong Huang, Chaerin Hong, Di Liang, Marco Fiorentino and Raymond G. Beausoleil.