%0 Journal Article %T Compact cryogenic self-aligning fiber-to-detector coupling with losses below one percent %A Miller, Aaron J. %A Lita, Adriana E. %A Calkins, Brice %A Vayshenker, Igor %A Gruber, Steven M. %A Nam, Sae Woo %J Optics Express %D 2011 %V 19 %N 10 %F Miller_etal2011 %O exported from refbase (https://db.rplab.ru/refbase/show.php?record=666), last updated on Wed, 14 Dec 2011 20:50:10 -0600 %X We present a compact packaging technique for coupling light from a single-mode telecommunication fiber to cryogenic single-photon sensitive devices. Our single-photon detectors are superconducting transition-edge sensors (TESs) with a collection area only a factor of a few larger than the area of the fiber core which presents significant challenges to low-loss fiber-to-detector coupling. The coupling method presented here has low loss, cryogenic compatibility, easy and reproducible assembly and low component cost. The system efficiency of the packaged single-photon counting detectors is verified by the “triplet method” of power-source calibration along with the “multiple attenuator” method that produces a calibrated single-photon flux. These calibration techniques, when used in combination with through-wafer imaging and fiber back-reflection measurements, give us confidence that we have achieved coupling losses below 1 % for all devices packaged according to the self-alignment method presented in this paper. %K TES %P 9102-9110