  We demonstrate temporal group delays in coherently-coupled high-Q
multi-cavity photonic crystals, in an all-optical analogue to
electromagnetically induced transparency. We report deterministic control of
the group delay up to 4x the single cavity lifetime in our CMOS-fabricated
room-temperature chip. Supported by three-dimensional numerical simulations and
theoretical analyses, our multi-pump beam approach enables control of the
multi-cavity resonances and inter-cavity phase, in both single and double
transparency peaks. The standing-wave wavelength-scale photon localization
allows direct scalability for chip-scale optical pulse trapping and
coupled-cavity QED.
