Ultracompact optical buffers on a silicon chip

Fengnian Xia, Lidija Sekaric, Yurii Vlasov

Research output: Contribution to journalArticlepeer-review


On-chip optical buffers based on waveguide delay lines might have significant implications for the development of optical interconnects in computer systems. Silicon-on-insulator (SOI) submicrometre photonic wire waveguides are used, because they can provide strong light confinement at the diffraction limit, allowing dramatic scaling of device size. Here we report on-chip optical delay lines based on such waveguides that consist of up to 100 microring resonators cascaded in either coupled-resonator or all-pass filter (APF) configurations. On-chip group delays exceeding 500ps are demonstrated in a device with a footprint below 0.09mm2. The trade-offs between resonantly enhanced group delay, device size, insertion loss and operational bandwidth are analysed for various delay-line designs. A large fractional group delay exceeding 10 bits is achieved for bit rates as high as 20Gbps. Measurements of system-level metrics as bit error rates for different bit rates demonstrate error-free operation up to 5Gbps.

Original languageEnglish (US)
Pages (from-to)65-71
Number of pages7
JournalNature Photonics
Issue number1
StatePublished - Jan 2007
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


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