High bandwidth (2 GHz km) large core (0.5-1.0 mm) GI polymer optical fiber

Silica-based single-mode (SM) optical fiber has been extensively studied and used for long haul communication because of its high transparency and high bandwidth. However, since the core diameter of the SM fiber is only 5-10 μm, the slight amount of displacement in fiber connection causes a large coupling loss, which will dramatically increase the total costs in the FTTH and interconnection. A Polymer Optical Fiber (POF) with a large core diameter (0.5-1.0 mm) is one of promising candidates to solve this problem. However, all commercially available POFs have been of the step-index (SI) type, so the bandwidth is only about 5 MHz km. Very recently, high-bandwidth graded-index (GI) POF with a 0.5-1.0 mm diameter has been successfully prepared at Keio University for the first time