A multichannel impedance-sensing CMOS chip for the readout of noninvasive light detectors in silicon photonics (SiP) is presented. The performance of the lock-in phase-sensitive demodulator is improved thanks to a capacitive feedback transimpedance amplifier (TIA) equipped with an active discharge network, able to keep a dc output offset lower than 3 mV for leakage currents up to 4 nA while injecting a noise lower than 40 fA/sqrt(Hz). The addition of a sensor capacitance compensation system at the input of the chip allows a 30-fold increase of the stimulation amplitude, enabling the tracking of sub-picoSiemens conductance variations on a baseline of few uS, with a bandwidth of 70 Hz. The chip performance opens the way to multipoint monitoring of complex photonic systems, addressing the challenges posed by the growing complexity of these architectures.

Wide Dynamic Range Multichannel Lock-In Amplifier for Contactless Optical Sensors with Sub-pS Resolution

Zanetto F.;Guglielmi E.;Toso F.;Sampietro M.;Ferrari G.
2020

Abstract

A multichannel impedance-sensing CMOS chip for the readout of noninvasive light detectors in silicon photonics (SiP) is presented. The performance of the lock-in phase-sensitive demodulator is improved thanks to a capacitive feedback transimpedance amplifier (TIA) equipped with an active discharge network, able to keep a dc output offset lower than 3 mV for leakage currents up to 4 nA while injecting a noise lower than 40 fA/sqrt(Hz). The addition of a sensor capacitance compensation system at the input of the chip allows a 30-fold increase of the stimulation amplitude, enabling the tracking of sub-picoSiemens conductance variations on a baseline of few uS, with a bandwidth of 70 Hz. The chip performance opens the way to multipoint monitoring of complex photonic systems, addressing the challenges posed by the growing complexity of these architectures.
Integrated photonics
lock-in front-end
low-noise
microsensors
transimpedance amplifier (TIA)
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embargo fino al 31/12/2020

Descrizione: Accepted manuscript
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11311/1146033
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