Design of launching condition in optical module through ballpoint-pen interconnect for graded-index plastic optical fiber

We investigate the launching condition dependence of the data transmission quality for the ballpoint-pen interconnect of the graded-index plastic optical fibers (GI POFs) to obtain design guidelines for its optimum optical module. The result shows that bit error rates can be significantly improved by using 30-μm offset launching condition for the core diameter of 80 μm despite decrease of detected power. This is attributed to the reflection noise reduction because of decreased self-coupled power to laser cavity, which is caused by different propagation axis between incident beam and backreflected beam. This suggests that sufficient offset launching is suitable for the optical module for the ballpoint-pen interconnect of the GI POF.