A single-chip CMOS optical microspectrometer with light-to-frequency converter and bus interface

A single-chip CMOS optical microspectrometer containing an array of 16 addressable Fabry-Perot etalons (each one with a 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 full-width half-maximum (FWHM) = 18 nm. Frequency output and serial bus interface allow easy multisensor and multichip interfacing using a microcontroller or a personal computer. Power consumption is 1250 μW for a clock frequency of 1 MHz.