Figure 2

Experimental setup. (a) Setup for laser annealing and characterization at room temperature. (b) Setup for characterization at \({-}80^{\circ}\mathrm{C}\). In (a), LD1 and LD2 are overlapped such that high-power laser from LD2 can be focused on the APD’s active area by focusing LD1 onto it. LD1 is also used for measuring SLiKs’ photon detection efficiency. The detector module is mounted on an XYZ translation stage, which can move between the laser setup and camera. The free-space portion of the setup is enclosed in a light-tight box. In (b), diverging weak coherent pulses are applied on APDs for full characterization. SM: single-mode optic fiber; MM: multi-mode optic fiber; O/E: optical-to-electrical.