This paper presents N-well Schottky diodes for high speed optical detection in 28nm CMOS technology. These diodes enable fully integrated CMOS optical receivers suited for the 850, 1310 and 1550nm telecommunication bands. The measured 1310 and 1550nm DC responsivity is 0.71mA/W and 0.16mA/W respectively at 1.5V reverse bias when backside illumination is performed while the 850nm responsivity is 0.27mA/W at the same biasing when frontside illumination is done. This is the first reported CMOS photodetector demonstrated at these three wavelengths. The measured capacitance-to-area ratio at zero bias is 1.7mF/m2.