Saturation effects in heterodyne detection with Geiger-mode InGaAs avalanche photodiode detector arrays

Area of Science:

• Optoelectronics
• Photon Counting Detectors
• Heterodyne Detection Systems

Background:

• Avalanche photodiode (APD) arrays in Geiger mode are used for photon counting.
• Saturation effects in finite pixel arrays degrade performance at high photon fluxes.
• Doppler frequency resolution and signal-to-noise ratio (SNR) are critical performance metrics.

Purpose of the Study:

• To report the first demonstration of heterodyne detection of a glint target using an InGaAs APD array in Geiger mode.
• To derive analytical expressions for Doppler resolution and SNR considering APD saturation.
• To determine optimal local oscillator power for improved system performance.

Main Methods:

• Utilized an InGaAs avalanche photodiode detector (APD) array operating in Geiger mode.
• Employed heterodyne detection techniques for glint target analysis.
• Derived analytical expressions to model the impact of saturation effects on performance metrics.

Main Results:

• Successfully demonstrated heterodyne detection with an InGaAs APD array.
• Developed analytical models quantifying the degradation of Doppler resolution and SNR due to APD saturation.
• Identified that optimal local oscillator power can be numerically determined from the derived SNR expression.

Conclusions:

• The study presents a novel application of InGaAs APD arrays for heterodyne detection.
• Analytical expressions provide a method to understand and mitigate saturation effects in photon-counting arrays.
• The findings enable optimization of heterodyne detection systems for improved performance in high-flux environments.