Corrugated quantum well infrared photodetectors (C-QWIPs) utilize total internal reflection to couple normal incident light into the detectors. In this work, we performed a systematic study on C-QWIPs with cutoff wavelength&lgr;cranging from 5 to 17.3 &mgr;m and device areas ranging from50×50 &mgr;m2to500×500 &mgr;m2.We found that the coupling efficiency of the C-QWIPs is, indeed, independent of both the detection wavelength and the pixel size, as expected. Compared to devices with a standard 45° edge coupling, the C-QWIP increases the background photocurrent to a dark current ratio by a factor between 2.4 and 4.4, thereby increasing the background limited temperature by 3–5 K. At the same time, the detectivityD*is also increased by a factor around 2.4. For&lgr;c=9.4 &mgr;m,the peak detectivityDp*and the blackbody detectivityDbb*at 78 K are measured to be4.5×1010 cm Hz/Wand4.5×109 cmHz/W,respectively. ©1997 American Institute of Physics.