Tunable add-drop filter using an active whispering gallery mode microcavity

Faraz Monifi, Şahin Kaya Özdemir, Lan Yang

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


An add-drop filter (ADF) fabricated using a whispering gallery mode resonator has different crosstalks for add and drop functions due to non-zero intrinsic losses of the resonator. Here, we show that introducing gain medium in the resonator and optically pumping it below the lasing threshold allows not only loss compensation to achieve similar and lower crosstalks but also tunability in bandwidth and add-drop efficiency. For an active ADF fabricated using an erbium-ytterbium co-doped microsphere, we achieved 24-fold enhancement in the intrinsic quality factor, 3.5-fold increase in drop efficiency, bandwidth tunability of 34 MHz, and a crosstalk of only 2%.

Original languageEnglish (US)
Article number181103
JournalApplied Physics Letters
Issue number18
StatePublished - Oct 28 2013

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)


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