Abstract: An optoelectronic device (20, 50) includes a planar substrate (30), an optical bus (40, 82, 84, 96, 140, 150, 180, 182, 224) disposed on the substrate and configured to convey coherent radiation through the bus, and an array (32, 72) of sensing cells (34, 74, 90, 160, 170, 200, 212, 380) disposed on the substrate. Each sensing cell includes at least one tap (92, 94, 144, 146, 226, 228) coupled to extract a portion of the coherent radiation propagating through the optical bus, an optical transducer (36, 108, 162, 172, 202, 204, 214) configured to couple optical radiation between the sensing cell and a target external to the substrate, and a receiver (114, 174, 178, 216, 218), which is coupled to mix the coherent radiation extracted by the tap with the optical radiation received by the optical transducer and to output an electrical signal responsively to the mixed radiation.