Dispersive Grating

Given that cooking is on so many minds this afternoon (including mine), I have to agree to "dispersive grating" does sound like a messy and/or distributed method for grating carrots, cheese or turnips. But that's not the "dispersive grating" that UC San Diego electrical engineering PhD student Dawn Tan developed.

Scanning electron micrograph of dispersive grating before deposition of SiO2 overcladding. (Decorative blue filter added to image.)  Image credit: UC San Diego / Dawn Tan

Her dispersive grating is for manipulating light on the nanoscale in order to compress pulses of light on computer chips. This kind of on-chip pulse compression is crucial for making the optical interconnects that will replace the copper wires that connect chips in computers of the future.

Read more about this silicon photonics advance published in the journal Nature Communications.

On-Chip Light Pulses / Nature Communications

The idea of using light to carry information around within computers has been around for a long time, but making it happen has been difficult. Electrical engineers from UC San Diego took an important step forward when they created a light pulse compressor that works on silicon chips. Compressing light pulses on chips will be necessary to realize optical time division multiplexing or OTDM.

“In communications, there is this technique called optical time division multiplexing or OTDM, where different signals are interleaved in time to produce a single data stream with higher data rates, on the order of terabytes per second. We’ve created a compression component that is essential for OTDM,” said electrical engineering PhD student Dawn Tan, the first author on a new Nature Communications paper that describes the work.

The UC San Diego electrical engineers say they are the first to report a pulse compressor on a CMOS-compatible integrated platform that is strong enough for OTDM.

“In the future, this work will enable integrating multiple ‘slow’ bandwidth channels with pulse compression into a single ultra-high-bandwidth OTDM channel on a chip. Such aggregation devices will be critical for future inter- and intra-high speed digital electronic processors interconnections for numerous applications such as data centers, field-programmable gate arrays, high performance computing and more,” said Yeshaiahu Fainman, a professor in the Department of Electrical and Computer Engineering in the UC San Diego Jacobs School of Engineering and the last author on the new paper.

Scanning electron micrograph of dispersive grating before deposition of SiO2 overcladding. It is this dispersive grating that is responsible for the record breaking pulse compression. (Decorative blue filter added to image.)  Image credit: UC San Diego / Dawn Tan

Scanning electron micrograph of dispersive grating before deposition of SiO2 overcladding. It is this dispersive grating that is responsible for the record breaking pulse compression. (Decorative blue filter added to image.)  Image credit: UC San Diego / Dawn Tan