鷹野君（OB）の成果が IEEE Sensors Journal に受理されました。

プラスチック光ファイバ中のモード間相対遅延に基づく電気領域干渉センシングを提案した鷹野君（OB）の論文が、IEEE Sensors Journalに受理されました。

R. Takano, M. A. Soto, and Y. Mizuno, “Electrical-domain interference sensing driven by relative modal delay in polymer optical fibers,” IEEE Sens. J., accepted.

This paper reports a previously unobserved interference phenomenon that manifests directly in the electrical spectrum of a photodetected signal when light propagates through polymer optical fiber (POF)-based single-mode–multimode–single-mode (SMS) structures. Unlike some conventional fiber sensors that rely on optical-spectrum interrogation, the proposed approach exploits multimode propagation and modal beating to generate well-defined interference features in the electrical domain. These features appear at sub-cutoff wavelengths of standard single-mode fibers (e.g., 1070 nm) and vanish at 1550 nm, confirming their multimodal origin. When a 57 cm POF segment is used, the interference dips shift reproducibly and reversibly under applied axial strain (0–611 µε), enabling high-speed strain sensing using only electrical spectrum analysis. The influence of POF length and source bandwidth is also experimentally investigated, revealing non-monotonic dip-spacing behavior and a systematic frequency downshift with increasing bandwidth, consistent with a relative modal-delay mechanism. The concept is further extended to displacement sensing by introducing a variable air gap between silica fibers, achieving sensitivities up to ~3.7 MHz/µm and potentially enabling nanometer-scale resolution. The simplicity, low cost, and fast response of this electrical-domain interrogation scheme make it a promising alternative to conventional optical-domain fiber sensors for real-time strain and displacement monitoring.