Study of one-shot/long time range/ultrafast optical waveform measurement system using frequency domain optical correlation technique

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01837
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 30020:Optical engineering and photon science-related
• Research Institution: Saitama University
• Principal Investigator: Shioda Tatsutoshi 埼玉大学, 理工学研究科, 准教授 (10376858)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 光計測

Outline of Final Research Achievements

This study proposed the frequency-domain optical correlation (FDOC) technology as a new optical waveform measurement method. By using the FDOC, the spectrum of the signal under test is scanned in the frequency domain and the correlation value with the source signal is obtained. The optical waveform is obtained by applying inverse Fourier transformation to the acquired correlation spectrum. Since the signal is processed in the frequency domain, it will not be limited by the cutoff frequency of electronic devices such as photoelectric converters, and it becomes possible to measure arbitrary optical waveform at ultrahigh speed. In this project, an SSB optical modulator as an optical frequency shifter was installed in an optical loop circuit for continuous spectral scanning of signals. It was constructed to enable frequency scanning in the 100 GHz range, and both simulations and experiments were conducted to investigate and confirm the principle.

Free Research Field

光計測システム

Academic Significance and Societal Importance of the Research Achievements

ピコ秒やフェムト秒時間領域を扱う超高速光技術は、光化学反応の反応素過程やレーザー加工の動力学の解析などの応用が必要とされている。ポンプ・プローブ法や自己相関器、光サンプリングオシロスコープは光パルスの光波形を捉えることができる。ところが、任意波形やシングルショット計測は困難である。そこで、我々は周波数領域の相関法を新たに提案してスペクトル領域で高密度に光波形を測定できる手法を開発した。本手法は原理的にサブピコ秒からピコ秒時間分解能で、数10～100 ps程度の長い時間領域の性能が得られると期待されている。本課題では単一の光検出器でピコ秒前後の分解能をもったシングルショット波形計測法を提案した。