Low noise, high speed laser detectors sensitive to eye-safe laser wavelengths (near 1.5 micrometer) are of great importance in next-generation laser rangefinders, or laser radar applications. Improved signal-to-noise performance, and thus improved range or decreased laser power, can be achieved through the use of avalanche photodiodes (APD) in place of unity gain PIN detectors. The noise behavior of the APD is crucial in determining the overall performance of these systems. We will discuss intrinsic and extrinsic limits to performance for several different APD material systems sensitive to eye-safe lasers, including a detailed comparison of HgCdTe, InGaAs, and several other material systems.
Andrew T. Hunter,
"Avalanche photodiodes for detection of eye-safe laser pulses", Proc. SPIE 3629, Photodetectors: Materials and Devices IV, (7 April 1999); doi: 10.1117/12.344561; https://doi.org/10.1117/12.344561