成果報告書詳細
管理番号20160000000258
タイトル*平成27年度中間年報 エネルギー・環境新技術先導プログラム プラスチック光ファイバが創る超省電力8Kネットワーク社会の実現
公開日2016/4/29
報告書年度2015 - 2015
委託先名学校法人慶應義塾
プロジェクト番号P14004
部署名イノベーション推進部
和文要約
英文要約Title:Advanced Research Program for Energy and Environmental Technologies / Realization of Ultralow Power Consumption 8K Network Society based on Plastic Optical Fiber (FY2015-FY2016) FY2015 Annual Report

For the 2020 Tokyo Olympics and Paralympics, ultra-high definition (UHD) display has been rapidly developed for video formats with 4K and 8K resolutions. Current UHD displays require uncompressed video data transfer through interfaces from set-top boxes and smartphones. However, conventional metal interfaces such as serial digital interfaces are not suitable to the consumer applications because they suffer from electromagnetic interference which degrades WiFi throughput. In this project, we have proposed and developed optical interface based on graded-index plastic optical fiber (GI POF) for upcoming 4K/8K era at home. Recently, we have developed consumer-friendly pluggable interconnects of GI POFs based on ballpoint-pen technologies, enabling easy connection, low-cost production, and fiber end-face protection of GI POFs. In the ballpoint-pen interconnect, output beam from the GI POF is expanded and collimated through the ball lens, which is mounted on the GI POF end face by the ballpoint-pen production technology. In actual optical systems, however, misalignment tolerance of the ballpoint-pen connector depends on launching condition because the resulting collimated beam characteristics depend on launched modes in the GI POF. For a multimode vertical cavity surface emitting laser (VCSEL), the ballpoint-pen connector performance can be influenced by a change in laser driving current on which transverse oscillation modes of the VCSEL depend. This year, we have investigated dependence of the misalignment tolerance of the ballpoint-pen interconnect on launching condition using a multimode VCSEL. The lateral-offset dependence of the coupling loss on driving current and launching beam position are evaluated to obtain design guideline for applying the ballpoint-pen interconnect to data communications with multimode VCSELs. The results show that the lateral-misalignment dependence of the coupling losses became stronger with an increase in laser driving current for center launching with a multimode VCSEL. This was attributed to the more expanded beam from the GI POF because of the higher-order guided mode launching, which resulted from additional oscillation of the higher-order transverse modes of the VCSEL. This driving-current dependence of the coupling loss was decreased by using offset launchings. For a radial launching offset of 20 μm, we could obtain coupling losses below 1 dB for lateral coupling offsets of  50 μm with little dependence on the driving current. This suggests that high-quality data transmissions with little noises due to the dynamically-changed coupling loss can be achieved for misaligned connection of the GI POFs by optimizing launching systems.
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