A 9×9 Single-Photon Avalanche Photodiode (SPAD) array with a 10-channel time-to-digital converter and an integrated laser diode driver fabricated in 0.35 μm HV- CMOS technology were used to carry out time domain diffuse optics measurements of optical phantoms. The average optical power of 20 μW was achieved by the laser diode transmitter at the repetition rate of 500 kHz with a pulse width of 80 ps. The resolution of the TDC and the measured instrument response function (IRF) of the system were ~65 ps and ~190 ps, respectively. The power consumption of the proposed system was 180 mW. Measurements showed that with the proposed system a perturbation with a different absorption property than in surrounding material at the depth of 15 mm could be recognized. In addition, in in vivo measurement with the proposed components, hemodynamic changes in volunteer’s arm during a venous occlusion were detected.
Jansson Jussi-Pekka, Jahromi Sahba, Haapalainen Kalle, Juttula Harri, Mäkynen Anssi, Nissinen Jan
A4 Article in conference proceedings
Place of publication:
2020 IEEE International Instrumentation and Measurement Technology Conference, I2MTC 2020
J. Jansson, S. Jahromi, K. Haapalainen, H. Juttula, A. Mäkynen and J. Nissinen, “An integrated 9×9 SPAD array with a 10-channel TDC and a CMOS laser diode driver for a wearable time-domain diffuse optics optode,” 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), Dubrovnik, Croatia, 2020, pp. 1-5, doi: 10.1109/I2MTC43012.2020.9129341
Read the publication here: