A CMOS optical microspectrometer with light-to-frequency converter, bus interface, and stray-light compensation

A single-chip CMOS optical microspectrometer containing an array of 16 addressable Fabry–Perot (F–P) etalons (each one with different resonance cavity length), photodetectors, and circuits for readout, multiplexing, and driving a serial bus interface has been fabricated in a standard 1.6m CMOS technology (chip area 3 9 4 2 mm). The result is a chip that can operate using only four external connections (including dd and ss) covering the optical range of 380–500 nm with FWHM = 18 nm. Frequency output and serial bus interface allow easy multisensor, multichip interfacing using a microcontroller or a personal computer. Also, stray-light compensation techniques are implemented. Power consumption is 1250 W at a clock frequency of 1 MHz.