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 1.6-μm CMOS technology (chip area 3.9 × 4.2 mm² ). The result is a chip that can operate using only four external connections (including V_dd and V_ss) covering the optical range of 380-500 nm with FNVHM = 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 μW at a clock frequency of 1 MHz