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Updated: May 21, 2026

Microwave Photonics Systems Based on Whispering-gallery-mode Resonators
Published on: August 5, 2013
Critical coupling control of a microresonator by laser amplitude modulation
Jong H Chow1, Michael A Taylor, Timothy T-Y Lam
1Centre for Gravitational Physics, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200, Australia. jong.chow@anu.edu.au
Abstract:
We present a laser amplitude modulation technique to actively stabilize the critical coupling of a microresonator by controlling the evanescent coupling gap from an optical fiber taper. It is a form of nulled lock-in detection, which decouples laser intensity fluctuations from the critical coupling measurement. We achieved a stabilization bandwidth of ∼ 20 Hz, with up to 5 orders of magnitude displacement noise suppression at 10 mHz, and an inferred gap stability of better than a picometer/√Hz.
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