清住君（OB）の論文が Journal of Lightwave Technology に掲載されました。

光相関領域反射計の折り返しノイズの抑制法を提案した清住君（OB）の論文が、Journal of Lightwave Technology に掲載されました。

T. Kiyozumi, S. Yoshida, K. Noda, and Y. Mizuno, “Ghost-peak suppression for optical correlation-domain reflectometry by gigahertz-order frequency shift,” J. Lightwave Technol., vol. 42, no. 18, pp. 6578-6584 (2024).

Optical correlation-domain reflectometry (OCDR) is an interference-based method for measuring the reflectivity distribution of optical fibers using periodic frequency-modulated light. OCDR yields experimental results that cannot be explained solely by existing theories, such as the appearance of ghost peaks at positions where reflection points are not anticipated, thus indicating insufficient theoretical foundation. To elucidate this behavior, the “beat-spectrum theory” has been proposed. Although this theory suggests that ghost peaks are caused by beat spectrum folding, no conclusive evidence based on measurements of the folded beat spectrum has been provided, and no solutions have been proposed for addressing ghost peaks. In this study, we test this hypothesis by measuring the folded beat spectrum. Additionally, we experimentally demonstrate that by applying gigahertz-order frequency shifts to a reflected light using a double-sideband modulator, beat spectrum folding can be mitigated and ghost peaks can be effectively suppressed.