A two-color CMOS optical detector circuit

This paper presents the design of a CMOS based circuit capable of detecting two different optical wavelengths within the visible region. The circuit is designed using a standard CMOS process technology by exploiting the double-barrier photo detection structure inherent in CMOS process technology. It is capable of discriminating between an optical signal at 490nm (blue) and 710 nm (red). The circuit is an ideal candidate for two-color optical detection of fluorescent emission in microarray analysis widely used in biomedical and chemical diagnosis. The authors briefly review optical detection in CMOS based photodiodes, give optical characterization results obtained from the photodiodes, and present the two-color circuit steady-state analysis along with simulation results of its operation.