An image sensor includes a plurality of photodiodes disposed in a semiconductor layer, a first isolation layer, and a dielectric filler. The dielectric filler is disposed in a trench in the first isolation layer, and the first isolation layer is disposed between the semiconductor layer and the dielectric filler. At least one additional isolation layer is disposed proximate to the first isolation layer, and a plurality of light channels in the at least one additional isolation layer extend through the at least one additional isolation layer to the dielectric filler. The plurality of light channels is disposed to direct light into the plurality of photodiodes.