A sensor circuit, comprising: - a silicon photomultiplier, SiPM, sensor including an array of avalanche photodiode, APD, elements that are connected in parallel between a common cathode and a common anode of the SiPM sensor, the APD elements being configured to generate photon detection currents when detecting photons of incoming light signals (12, 16); - a voltage source, configured to apply a reversed bias voltage (Vb) across the SiPM sensor and between the common cathode and anode, to let each of the APD elements operate in reverse-biased Geiger mode, and to let the array of APD elements operate in integration mode in which an output current by the SiPM sensor is formed from a sum of the photon detection currents from the APD elements such that the output current closely follows amplitude modulations of the incoming light signals (12, 16) that oscillate in time corresponding to frequencies within a predetermined frequency range (fo); - a current-to-voltage converter, electrically connected with an input terminal to the cathode of the SiPM sensor, and configured to convert a current from the cathode of the SiPM sensor into a voltage and provide said voltage on an output terminal of said converter; - a limiting bias circuit connected between the voltage source and the common anode of the SiPM sensor, wherein the bias circuit is configured to limit a maximum average current passing via the common anode through SiPM sensor by lowering at the common anode the reverse bias voltage (Vb) applied across the SiPM sensor in response to an increase in the output current by the SiPM sensor passing through the common anode, and wherein the bias circuit is further configured to present an AC load impedance for alternating currents corresponding to frequencies within the predetermined frequency range (fo) generated by the APD elements at the common anode, as well as to present a DC load impedance, such that said AC load impedance is lower than said DC load impedance and that oscillations in the bias voltage (Vb) across the SiPM sensor at frequencies within the predetermined frequency range (fo) are suppressed or eliminated. - a silicon photomultiplier, SiPM, sensor including an array of avalanche photodiode, APD, elements that are connected in parallel between a common cathode and a common anode of the SiPM sensor, the APD elements being configured to generate photon detection currents when detecting photons of incoming light signals (12, 16); - a voltage source, configured to apply a reversed bias voltage (Vb) across the SiPM sensor and between the common cathode and anode, to let each of the APD elements operate in reverse-biased Geiger mode, and to let the array of APD elements operate in integration mode in which an output current by the SiPM sensor is formed from a sum of the photon detection currents from the APD elements such that the output current closely follows amplitude modulations of the incoming light signals (12, 16) that oscillate in time corresponding to frequencies within a predetermined frequency range (fo); - a current-to-voltage converter, electrically connected with an input terminal to the cathode of the SiPM sensor, and configured to convert a current from the cathode of the SiPM sensor into a voltage and provide said voltage on an output terminal of said converter; - a limiting bias circuit connected between the voltage source and the common anode of the SiPM sensor, wherein the bias circuit is configured to limit a maximum average current passing via the common anode through SiPM sensor by lowering at the common anode the reverse bias voltage (Vb) applied across the SiPM sensor in response to an increase in the output current by the SiPM sensor passing through the common anode, and wherein the bias circuit is further configured to present an AC load impedance for alternating currents corresponding to frequencies within the predetermined frequency range (fo) generated by the APD elements at the common anode, as well as to present a DC load impedance, such that said AC load impedance is lower than said DC load impedance and that oscillations in the bias voltage (Vb) across the SiPM sensor at frequencies within the predetermined frequency range (fo) are suppressed or eliminated.