The Measurement of Optical Interconnect Module Postsoldering Alignment Offsets and the Study of Its Influence on Optical Coupling Efficiency

In the process of the optical interconnection module soldering assembly, the mismatch of the thermal expansion coefficient between the substrate and printed circuit board would result in the production of alignment offset between light source devices and light-coupled devices, which would lead to light power loss. It is of great significance to study the optical interconnect module alignment offset in the assembly process to improve the optical interconnect module coupling efficiency. In this paper, an optical interconnection module key position postsoldering shift offset measurement system was established, and an optical interconnection module experimental sample was prepared. The key position postsoldering shift in the x- and y-directions was measured. The 3-D finite-element analysis model of a typical optical interconnect module was established, and postsoldering shift offsets were calculated after the finite-element analysis of the optical interconnect module under reflow soldering temperature load. The coupling efficiency simulation model of the optical interconnection module was established using the ZEMAX software, and the coupling efficiency was calculated according to the alignment offset measured in the experiment. The results revealed the following: the postsoldering alignment offsets in the x- and y-directions were 0.316 and 0.422 μm, respectively, and the synthetic alignment offset was 0.527 μm. The postsoldering alignment offset calculated using the finite-element simulation model was 0.436 μm, and its error was 17.2%, when compared with the measured value. The coupling efficiency of the optical interconnection module was 85.804% when the postsoldering alignment offset was 0.527 μm.