A Pixel-Embedded Charge-Pumping CMOS Photonic Mixer Device, Implementation and Perspectives

This paper reports on the implementation of a CMOS Photonic Mixer Device (PMD), which uses a new concept for demodulating photo-generated charges. The device uses a pair of PMOS transistors with an embedded photodiode to detect the intensity and phase of a modulated light signal. The charge demodulation, from photo-detector to the output, is accomplished exploiting the Charge Pumping phenomenon. Discovered in 1969, the Charge Pumping has been extensively used as a powerful analysis method for evaluate and quantify the degradation of MOS transistors. Experimental results, reported here, demonstrate that this phenomenon can also be employed as an alternative to the CCD charge transfer mechanism, which has been used for mixing photo-generated charges. The proposed PMD, compact and fully digitally controlled, is suitable to be organized in an array of pixels with embedded demodulating function.