1999 Fiscal Year Final Research Report Summary
Correlation Domain Spectroscopy by Frequency-Chirped Light
| Project/Area Number |
10450031
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied physics, general
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
ITO Hiromasa Research Institute of Electrical Communication, Tohoku University, Professor, 電気通信研究所, 教授 (20006274)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Koichiro Research Institute of Electrical Communication, Tohoku University, Research Associate, 電気通信研究所, 助手 (40302236)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Frequency-shifted Feedback Laser / Frequency chirp / Spectroscopy |
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| Research Abstract |
In this research, a new technique in spectroscopy ; correlation domain spectroscopy was studied as an application of a frequency-shifted feedback laser. The main outcomes of the research are following.
1. Correlation domain spectroscopy, theory and experiment.
A theoretical analysis is developed for a measurement of a impulse response of a sample by a continuous wave light. The technique was named the correlation domain spectroscopy. To demonstrate the correlation domain spectroscopy, a frequency-shifted feedback laser was used as a frequency-chirped light source, because the frequency-chirp of the laser output is highly linear. In the experiment, an impulse response of an optical fiber loop was measured. We succeeded to measure the impulse response with a temporal resolution of 5 ns. Since the technique uses the continuos wave light, it is possible to measure the materials with low optical damage threshold such as biological samples.
2. Measurement of dispersion of optical fiber
A frequency-shifted feedback laser with an erbium doped fiber as a gain medium. The advantage of the laser is a wide wavelength tunable range. The wavelength was tuned by varying the driving frequency of the intracavity acoustooptic modulator, and 10 nm tuning range was obtained. The another advantage is that the laser oscillates at 1.55 μm which is the wavelength of the optical communication. Combining these advantages, we have proposed and demonstrated a measurement of the group velocity dispersion and polarization mode dispersion of an optical fiber by use of the frequency-shifted feedback laser. In the experiment, the group velocity dispersion and the polarization mode dispersion were measured with resolutions of 0.1 ps/nm/km and 0.01 ps, respectively.
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