Transmitted signsl quality in ballpoint-pen interconnect of graded-index plastic optical fiber

We demonstrate that ballpoint-pen interconnect enabled better transmission for largelymisaligned connection of graded-index plastic optical fiber (GI POF) than conventional butt-coupling. This may result from the reduction of coupling loss and some noises such as modal noise and reflection noise by using the ballpoint-pen interconnect, where a ball lens is precisely mounted on a fiber end faces for ball-lens coupling of GI POFs. Moreover, we show that power penalties in the ballpointpen interconnect are lower for larger lateral offsets in spite of higher coupling loss. This is closely related to the reduction of reflection noise with an increase in lateral misalignment as the ballpoint-pen interconnect were laterally misaligned.