Critical coupling control of a microresonator by laser amplitude modulation

Chow, Jong H; Taylor, Michael A; Lam, Timothy T-Y; Knittel, Joachim; Sawtell-Rickson, Jye D; Shaddock, Daniel A; Gray, Malcolm B; McClelland, David E; Bowen, Warwick P

Critical coupling control of a microresonator by laser amplitude modulation

Date

2012-05-21

Authors

Chow, Jong H

Taylor, Michael A

Lam, Timothy T-Y

Knittel, Joachim

Sawtell-Rickson, Jye D

Shaddock, Daniel A

Gray, Malcolm B

McClelland, David E

Bowen, Warwick P

Publisher

Optical Society of America

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.