A novel fiber alignment shift measurement technique employing an ultra high precision laser displacement meter in laser-welded laser module packaging

A novel measurement technique employing an ultra high precision laser displacement meter (LDM) with a 20 nm resolution for probing the post-weld-shift (PWS) induced fiber alignment shifts in laser-welded laser module packaging is presented. The results show that the direction and magnitude of the fiber alignment shifts induced by PWS in laser-welded laser module packaging can be determined and measured in real time by four parameters: lateral shift(r), position angle (α), swing angle(θ), and tilt angle(ψ). This suggests that the PWS induced fiber alignment shifts may be corrected as long as the PWS direction and magnitude are determined. Therefore, the LDM technique can be used as an important tool for quantitative analyzing the effect of PWS on the fiber alignment shifts in laser-welded laser module packaging, and a reliable laser module with high yield and high performance for use in low-cost lightwave transmission systems can be developed and fabricated.