An excess noise measurement system for weak responsivity avalanche photodiodes

Abstract

A system for measuring, with reduced photocurrent, the excess noise associated with the gain in avalanche photodiodes (APDs), using a transimpedance amplifier front-end and based on phase-sensitive detection is described. The system can reliably measure the excess noise power of devices, even when the un-multiplied photocurrent is low (~10 nA). This is more than one order of magnitude better than previously reported systems and represents a significantly better noise signal to noise ratio. This improvement in performance has been achieved by increasing the value of the feedback resistor and reducing the op-amp bandwidth. The ability to characterise APD performance with such low photocurrents enables the use of low power light sources such as light emitting diode rather than lasers to investigate the APD noise performance.

Impact Ionization Coefficients in (Al x Ga1-x )0.52In0.48P and Al x Ga1-x As Lattice-Matched to GaAs

“…Due to the stochastic nature of the impact ionization process, the avalanche multiplication is accompanied by "excess noise" which increases with β/α ratio (k) for multiplication initiated by electrons [20]. Excess noise measurements were performed on these devices using the low-current noise measurement system of Qiao et al [21], which is a modified version of the system of Lau et al [22]. The results are shown in Fig.…”

Analysis and Design Consideration of a High Sensitivity Silicon Avalanche Photodiode Receiver for Low Frequency Applications

“…The receiver circuit bandwidth is determined with feedback resistance and capacitance, the junction capacitance of the APD and the operational amplifier gain bandwidth product [9]. The transimpedance gain for each tested receiver circuit was increased with the TIA feedback resistor until the bandwidth of 50 kHz was obtained.…”

“…The transimpedance gain equal to 10 7 V/A was set with a thin-film 10 MΩ feedback resistor R10. A feedback capacitor C14 provides compensation for the effects of the input capacitance, and stabilizes the circuit [5,[7][8][9]. The voltage signal from the TIA is then amplified with an AC-coupled post-amplifier, which removes the DC signal component and provides output voltage level adjustment.…”