  A photonic integrated circuit (PIC) comprised of an 11 cm multimode speckle
waveguide, a 1x32 splitter, and a linear grating coupler array is fabricated
and utilized to receive 2 GHz of radio-frequency (RF) signal bandwidth from 2.5
to 4.5 GHz using compressive sensing (CS). Incoming RF signals are modulated
onto chirped optical pulses which are input to the multimode waveguide. The
multimode waveguide produces the random projections needed for CS via optical
speckle. The time-varying phase and amplitude of two test RF signals between
2.5 and 4.5 GHz are successfully recovered using the standard penalized
$l_1$-norm method. The use of a passive PIC serves as an initial step towards
the miniaturization of a compressive sensing RF receiver.
