Stability over time has recently become a figure of merit of major importance to compare the performances of infrared focal plane arrays (FPA) of different technologies. Indeed, this parameter dictates how often the calibration of operational electro-optical systems has to be done, and thus reflects the availability of the system during an operational mission. Recent studies also showed that random telegraph signal (RTS) noise, which leads to flickering pixels, can strongly affect the image quality. Highlights :-Stability over time and RTS noise of a commercial T2SL midwave infrared FPA have been investigated.-RFPN/TN ratio stays lower than unity for more than 7 weeks-number of RTS pixels is as low as 10 for a 5-minutes long measurement

We developed an automated Random Telegraph Signal detection and characterization method, as well as a blinking noise and slow drift separation method adapted to focal plane arrays. Utilizing these methods, a study of the evolution of the number of RTS pixels and the amplitudes of the blinking signal as a function of the reverse bias voltage and temperature is conducted. It is shown that physical characteristics of RTS follow Arrhenius laws and increase with bias. Finally, the origin of the increase of the amplitude as a function of the reverse bias is discussed.

The temporal stability of the image quality of an infrared focal plane array (FPA) is one key parameter to consider for high performance imaging applications. It is generally evaluated through Residual Fixed Pattern Noise (RFPN) measurements realized after a two-point correction (TPC) and bad pixels exclusion. However, the effect of random telegraph signal (RTS) on temporal stability has never been quantified, the intermittent blinking of RTS pixels making measurements inherently complicated. In this paper, we propose a novel protocol and a novel data processing technique to fully characterize the temporal stability of an infrared FPA, thanks to simultaneous RFPN and RTS noise measurements. Using a robust statistics based on Median Absolute Deviation (MAD) leads to a more trustful RFPN evaluation, unaffected by the bad pixels exclusion step. This new protocol can be applied to any FPA technology, cooled or uncooled, operating in the [3-14µm] spectral domain. We chose to use a Type-II superlattice (T2SL) midwave infrared FPA integrated in a cryocooler at 80K. We show that the long-term stability of this 320x256 pixels FPA is excellent. The RFPN only slightly increases over 77 days, using a TPC that has been calculated on the first day of the measurements campaign. A simple offset update, compatible with operational contingencies, can further improve the temporal stability of this FPA. Only 0.3% of the pixels were affected by RTS noise at some moment. Those blinking pixels don't affect the RFPN evolution, which is a very encouraging result for T2SL detector technology.