Low-noise graded-index plastic optical fiber for significantly stable and robust data transmission

Internet traffic continues to grow with the increase of network-connected smartphones, tablets, televisions, and monitoring devices in the Internet-of-Things (IoT) era. This trend will be significantly accelerated by the introduction of ultrahigh-definition (UHD) imaging technologies in various applications, and existing optical networks including datacenter networks are under urgent development to accommodate this traffic. However, optical fibers have not been introduced into households located in optical network terminal areas, even though UHD device connections require decompressed high-volume data transmission at more than 100 Gb/s, where a multilevel modulation scheme is vital. In UHD applications, very short optical cables (typically less than several meters) are connected and disconnected by consumers in a manner similar to metal interface cables. Under such conditions, a data transmission quality is predominantly limited by noise and instability rather than bandwidth and loss. Here, we propose low-noise graded-index plastic optical fibers (GI POFs) that enable significantly stable and robust data transmission through strong mode coupling, whose mechanism is fundamentally different from that of silica optical fibers. The low-noise GI POF link eliminates the need for the precise fiber alignment, angled fiber facets, and optical isolators typically used in conventional links. Our proposed GI POF material paves the way for quick optical fiber connections for multilevel UHD video transmission, becoming the first 'capillaries of light' from optical network terminals in the IoT era.