A bootstrapped, low-noise, and high-gain photodetector for shot noise measurement

Abstract

We presented a low-noise, high-gain photodetector based on the bootstrap structure and the L-C (inductance and capacitance) combination. Electronic characteristics of the photodetector, including electronic noise, gain and frequency response, and dynamic range, were verified through a single-frequency Nd:YVO4 laser at 1064 nm with coherent output. The measured shot noise of 50 μW laser was 13 dB above the electronic noise at the analysis frequency of 2 MHz, and 10 dB at 3 MHz. And a maximum clearance of 28 dB at 2 MHz was achieved when 1.52 mW laser was illuminated. In addition, the photodetector showed excellent linearities for both DC and AC amplifications in the laser power range between 12.5 μW and 1.52 mW.

A Low-Noise, Large-Dynamic-Range-Enhanced Amplifier Based on JFET Buffering Input and JFET Bootstrap Structure

“…When the injected laser power is around 51 μW, the shot noise power is 12.5 dB higher than the electronic noise power at 2.0 MHz, and 9.8 dB at 4.0 MHz respectively under the transimpedance gain of 200 kΩ and 0.5 pF. Compared with the former Bell-state photodetector [4], even the SNR at 2.0 MHz is 0.5 dB smaller, the SNR at 4.0 MHz is largely boosted from the original 6.0 dB to the higher 9.8 dB. In addition, the dynamic range is largely extended from the original 1.52 mW to 11.22 mW in our new amplifier.…”

“…The need for low noise amplifier becomes even more urgent for optical Bell-states detection, where weak laser power of 50 μW at the wavelength of 1064 nm could be extracted from the optical parameter amplifier (OPA) [2,4]. Therefore, the optical noise or its squeezing and entanglement could be easily overwhelmed by the electronic noise at the interested 2.0 MHz.…”

“…Typically, the measured optical noise should be much higher than the electronic noise, i.e. large signal-to-noise ratio (SNR) of 10 dB or more at the analysis frequency of 2.0 MHz for a certain input laser power [1][2][3][4]. Conventionally, the SNR could be enlarged by boosting the current-to-voltage gain, increasing the input laser power, or equivalently by reducing the electronic noise at the analysis frequency of 2.0 MHz [3][4][5][6].…”

“…Limited by available laser power, much efforts have been focused on reducing electronic noise of amplifiers in quantum optics experiments [1,3,4].…”

“…However, one of critical challenges is that the input voltage noise of the op amp in the TIA would experience high-frequency noise voltage gain. So as to avoid this noise gain, it is necessary to keep the input voltage noise as small as possible, or equivalently to keep the photodiode capacitance as small as possible [3][4][5][6][7][8][9][10].…”