• 100 cascaded microrings form on-chip optical buffer

    All-optical information processing on a chip will require controllable buffering of optical signals.
    Feb. 1, 2007

    All-optical information processing on a chip will require controllable buffering of optical signals. While “slow-light” approaches are natural buffers of light, they are bulky and operate at bandwidths only up to the megahertz range. Researchers at IBM (Yorktown Heights, NY) have developed a non-slowed-light approach that shunts the optical signal into a series of up to 100 cascaded low-Q microring resonators; the whole device fits in a 0.09 mm2 area. Delay times of up to 500 ps were demonstrated; a delay of 10 bits was achieved at a 20 Gbit/s data rate.

    A silicon-on-insulator wafer with a 226 nm thick upper silicon layer was etched to form photonic-wire waveguides that confined light within a 0.1 µm2 cross section. Two designs were examined: coupled resonators with many rings cascaded in a series and all-pass filters, in which rings in parallel coupled light from one waveguide to the next with their individual delays summing to the total delay. The experimental control was a bent-waveguide delay line. The two designs were five times smaller than the control, but had three times the insertion loss. Contact Yurii Vlasov at [email protected].

    Sign up for Laser Focus World Newsletters
    Get the latest news and updates.

    Voice Your Opinion!

    To join the conversation, and become an exclusive member of Laser Focus World, create an account today!