Second order add/drop filter with a single ring resonator

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    2 Citations (Scopus)


    We show theoretically and experimentally how a flat-top second-order response can be achieved with a self-coupled single add-drop ring resonator based on two couplers with different splitting ratios. The resulting device is a 1x1 filter, reflecting light back in the input waveguide at resonating wavelengths in the passbands, and transmitting light in the output waveguide at all other non-resonating wavelengths. Different implementations of the filter have been designed and fabricated on a micron-scale silicon photonics platform. They are based on compact Euler bends - either U-bends or Lbends - and Multi-Mode Interferometers as splitters for the ring resonators. Different finesse values have been achieved by using either 50:50 MMIs in conjunction with 85:15 MMIs or 85:15 MMIs in conjunction with 95:05 double MMIs. Unlike ordinary lowest order directional couplers, the MMIs couple most of the power in the cross-port which make them particularly suitable for the topology of the self-coupled ring, which would otherwise require a waveguide crossing. Experimental results are presented, showing good agreement with simulations. The proposed devices can find applications as wavelength-selective reflectors for relatively broad-band lasers or used as 2x2 add-drop filters when two exact replicas of the device are placed on the arms of a Mach-Zehnder interferometer.
    Original languageEnglish
    Title of host publicationSilicon Photonics XII
    EditorsAndrew P. Knights, Graham T. Reed
    PublisherInternational Society for Optics and Photonics SPIE
    ISBN (Print)978-1-5106-0657-9
    Publication statusPublished - 1 Jan 2017
    MoE publication typeA4 Article in a conference publication
    EventSilicon Photonics XII: SPIE OPTO 2017 - San Francisco, United States
    Duration: 30 Jan 20171 Feb 2017

    Publication series

    SeriesProceedings of SPIE


    ConferenceSilicon Photonics XII
    Country/TerritoryUnited States
    CitySan Francisco


    • flat-top filters
    • integrated optics
    • multimode interference splitters
    • photonic integrated circuits
    • ring resonators
    • silicon photonics
    • WDM filters
    • Integrated optics
    • OtaNano


    Dive into the research topics of 'Second order add/drop filter with a single ring resonator'. Together they form a unique fingerprint.

    Cite this