Noise characteristics of short wavelength infrared InGaAs linear focal plane arrays

Abstract

A noise characteristics model is presented for short wavelength infrared (SWIR) focal plane arrays (FPAs). The model shows the relationship between noise and varying integration time. The experimental results for different SWIR InGaAs linear FPAs in the 1.0–1.7 μm and 1.0–2.4 μm spectral range can be well fitted by this model. The noise of InGaAs FPAs with the conventional process in the 1.0–1.7 μm spectral range is determined by the shot noise from the photodiode, which provides a direction for reducing the noise of FPAs. The noise of InGaAs FPAs with the improved process in the 1.0–1.7 μm spectral range is determined by the noise from the readout integrated circuit (ROIC), which is due to the lower shot noise from the dark current of the photodiode. The noise of InGaAs FPAs in the 1.0–2.4 μm spectral range shows a transition from the fixed-pattern noise to the shot noise with a decrease of temperature as indicated by the model. This reduction is mainly due to the higher dark current of photodiodes and the non-uniformity of the dark current. It could be expected that the noise characteristics model is appropriate for the other infrared FPAs. Further, gain constants and conversion efficiencies of the ROIC are obtained according to a signal to noise relationship of the FPAs.