cavity comprises two mirrors, with 29 ppm and 98 ppm power transmission respectively, separated by $2.6~\mathrm{mm}$. The chip assembly is placed in the standing wave of the optical cavity with the membrane $750~\mathrm{\mu m}$ from the high-transmission mirror, such that the membrane’s vibrations modulate the cavity’s resonant frequency [@thompson_strong_2008]. The optical mode intersects the membrane in the quadrant opposite the capacitor, and these two regions of the membrane move in phase for the mechanical mode of interest.

### Data Availability {#data-availability .unnumbered}

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

Author Contributions {#author-contributions .unnumbered}
--------------------

A.P.H., P.S.B., and M.D.U. conducted the experiment and analyzed data. A.P.H, P.S.B., M.D.U., R.W.P., and N.S.K. designed and constructed the measurement network. M.D.U. and R.W.P. designed and constructed the optical cavity. P.S.B. designed and fabricated the flip-chip device. A.P.H. and G.S. developed feedforward theory. A.P.H., P.S.B., M.D.U., B.M.B., G.S., K.W.L., and C.A.R. wrote the manuscript. C.A.R. and K.W.L. supervised the work. All authors commented on the results and manuscript.

Competing Financial Interests statement {#competing-financial-interests-statement .unnumbered}
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The authors declare no competing financial interests.

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