Basic study on measurement of seawater salinity using heterodyne doublepass interferometer

2015 Fiscal Year Final Research Report

• Project/Area Number: 25610143
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Meteorology/Physical oceanography/Hydrology
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: Asakawa Kenichi 国立研究開発法人海洋研究開発機構, 海洋工学センター, シニアスタッフ (40344288)
• Co-Investigator(Renkei-kenkyūsha): UEKI Iwao 国立研究開発法人海洋研究開発機構, 地球環境観測研究開発センター, グループリーダー代理 (60371712)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: ヘテロダイン干渉計 / ダブルパス干渉計 / HeNeレーザ / 半導体レーザ / 地球温暖化 / 海洋観測 / 塩分 / 大洋循環

Outline of Final Research Achievements

The object of this project is to show the possibility to realize an optical salinometer having high resolution and stability. First, we built a heterodyne double-pass interferometer with HeNe laser as a light source and evaluated its basic performance. As a result, it was confirmed that the temperature stability is improved by more than an order of magnitude, compared with the Michelson interferometer. Furthermore we incorporated a semiconductor laser as a light source. Although we could obtain interferometer output with sufficient signal to noise, it revealed that there is a problem with the lock-in amplifier for performing the heterodyne detection. We are going to try heterodyne detection using a computer without using the lock-in amplifier.

Free Research Field

海中工学