Thesis on Current-Assisted Photonic Demodulator for ToF Sensor

Hong Kong University of Science and Technology (HKUST) publishes a MSc thesis "Compact modeling of current-assisted photonic demodulator (CAPD) for time-of-flight CMOS image sensor" by Cristine Jin Delos Santos Estrada.

"A widely popular ToF sensor implementation is the current-assisted photonic demodulator (CAPD). While CAPD has been being used in ToF systems, its operation characteristics are difficult to predict because of a lack of a compact model describing its output current as a result of the incident light and modulating voltages. This problem further poses difficulty in establishing design considerations to achieve a good tradeoff in sensitivity, power, speed, and efficiency for such photonic demodulator.

In this work, a compact model for CAPD describing both the static and dynamic behavior of the device is proposed. An analytical expression relating the optical photogenerated current to the input bias and incident light intensity is derived by solving the continuity and drift-diffusion equations along the optical window of CAPD. The model has been extensively verified with numerical simulations, as well as with published experimental data."