  Silicon photonics (SiP) integrated coherent image sensors offer higher
sensitivity and improved range-resolution-product compared to direct detection
image sensors such as CCD and CMOS devices. Previous generation of SiP coherent
imagers suffer from relative optical phase fluctuations between the signal and
reference paths, which results in random phase and amplitude fluctuations in
the output signal. This limitation negatively impacts the SNR and signal
acquisition times. Here we present a coherent imager system that suppresses the
optical carrier signal and removes non-idealities from the relative optical
path using a photonic in-phase (I) and quadrature (Q) receiver via a $90^\circ$
hybrid detector. Furthermore, we incorporate row-column read-out and row-column
addressing schemes to address the electro-optical interconnect density
challenge. Our novel row-column read-out architecture for the sensor array
requires only $2N$ interconnects for $N^2$ sensors. An $8\times8$ IQ sensor
array is presented as a proof-of-concept demonstration with $1.2\times 10^{-5}$
resolution over range accuracy. Free-space FMCW ranging with 250um resolution
at 1m distance has been demonstrated using this sensor array.
