Measurement technology on transparent sample based on standing wave optical pulse generation

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K18852
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 21:Electrical and electronic engineering and related fields
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: Tanaka Yosuke 東京農工大学, 工学(系)研究科(研究院), 准教授 (20283343)
• Project Period (FY): 2018-06-29 – 2020-03-31
• Keywords: 散乱光計測 / 多モード光 / 光周波数コム / 歪み計測 / 温度計測 / 曲げ計測 / 分布計測

Outline of Final Research Achievements

The aim of this study is development of new technology on measuring strain, vibration, or temperature of a transparent or semitransparent sample. The proposed method generates standing wave optical pulse in the sample by injecting from both sides the multimode light composed of equally spaced spectral peaks in the frequency domain, where the spectral shape is appropriately controlled. Monitoring the scattered light produced by the standing wave optical pulse, the strain or temperature is measured. We used an optical fiber as a sample and successfully performed real-time distributed temperature measurements, which proved the validity of the proposed method. Furthermore, we also proposed and demonstrated curvature measurements using a multicore fiber Bragg grating, noticing the similarity between the mechanism of the scattering and the reflection by a fiber Bragg grating, which changes the center wavelength of the reflected light due to strain-induced grating pitch change.

Free Research Field

光エレクトロニクス

Academic Significance and Societal Importance of the Research Achievements

本研究の成果は、光パルス技術、光周波数コム技術、光計測技術等を結びつけ、新たな応用展開を進める足掛かりとなり、国内外の各研究分野の進展に貢献すると考えられる。具体的応用の点から、複数波長の散乱光に対する利得スペクトル整形を用いた分布計測は、散乱光強度から直接、温度や歪みが分かるため、測定高速化につながる利点がある。また、光ファイバ曲げセンサは、医療用カテーテルやロボットアーム等に埋め込み動作制御のフィードバックに利用すれば、より細やかな動作調整の実現につながる。以上の成果は、重要度が高まっている建造物の構造ヘルスモニタリングや、医用計測分野の発展につながると期待できる。