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

We design a low-noise, large-dynamic-range amplifier based on transimpedance amplifier (TIA) for detecting shot noise of 1064-nm laser in quantum optical experiments. Compared with a single-junction field-effect transistor (JFET) buffered TIA, the electronic noise is effectively 2.8 dB suppressed at the analysis of 2 MHz, and 4 dB suppressed at 4 MHz by means of a JFET bootstrap structure. Under the transimpedance gain of 200 kΩ and 0.5 pF, the measured shot noise at the injected laser power of 51 μW is 12.5 dB above the electronic noise at 2 MHz, and 9.8 dB at 4 MHz. With adjustment of bias condition of the bootstrap structure and application of a L-C (inductance and capacitance) structure, the dynamic range is largely boosted from the original 1.52 to 11.22 mW. The amplifier meets the requirement of SNR for Bell-state detection in quantum optical experiments.