During the last decade, the QWIPs technology has improved from start to an undeniable maturity level. High performance focal plane arrays have already been realized (ATT, Lockheed-Martin, JPL, . . .) with a spectacular format increase ranging from 128 by 128 up to 640 by 480, and images from bicolor 256 by 256 arrays have been shown last year. All these devices illustrate the high potential of the QWIP technology. In the same time, the modeling of detection mechanism has advanced to permit the present design of specific detectors and their optimization in given operating environments (near 77 K detector temperature for instance). In this communication, we summarize our recent technological studies leading to the next generation of very large infrared detector arrays. We present the QWIP ultimate performances allowed by the standard dual III - V technological processes developed at THOMSON CSF, in terms of pixel size, array filling factor or connectics. The influence of the pixel size for the grating optical coupling is analyzed. We finally include in this analysis our results for more complex devices like multispectral infrared detectors.