The investigation of underwater vibration positioning system by multi-wavelength fiber laser

• Main Authors: CHEN, XIN-JIE, 陳信傑
• Other Authors: CHENG, HSU-CHIH
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/7tn7ev

碩士 === 國立虎尾科技大學 === 光電工程系光電與材料科技碩士班 === 107 === In this thesis, we use a multi-wavelength ring laser system as the wavelength selection element .In this system, we using multiple fiber Bragg gratings (FBG) of different wavelengths as comb filters, multi-wavelength lasers are generated by adjusting the polarization controller (PC). In experiment, due to the reflection wavelength of the fiber Bragg grating is highly sensitive to the external strain of temperature or vibration, we measure the ex-ternal strain through the offset of the center wavelength of the fiber Bragg grating, and we will use this feature to measure the underwater vibration source. The multi-wavelength ring laser system can be combined with multiple Bragg gratings to achieve multi-point measurement. Applying a vibration signal between multiple Bragg gratings, the time difference of the signal measured by each fiber Bragg grating is displayed on the oscilloscope through the photo detector (PD). Finally, use the formula to calculate the location of the vibration source.