Title page for etd-0623115-001116


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URN etd-0623115-001116
Author Chun-Sheng Shin
Author's Email Address No Public.
Statistics This thesis had been viewed 5585 times. Download 594 times.
Department Electro-Optical Engineering
Year 2014
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Fiber Laser Sensor using PCF-based Mach-Zehnder Interferometer Formed by Misalinged Splicing
Date of Defense 2015-06-26
Page Count 90
Keyword
  • fiber laser sensor
  • fiber laser
  • fiber sensor
  • Photonic crystal fiber
  • Mach-Zehnder interferometer
  • Abstract Optical sensors based on fiber interferometers have been investigated extensively due to their significant advantages of compact size, low cost and immunity to electromagnetic interference. However, their accuracy is poor due to the broad 3-dB bandwidth and low extinction ratio of the interference spectrum. In this dissertation, we fabricate a fiber Mach-Zehnder interferometer (MZI) by splicing a photonic crystal fiber (PCF) with SMFs with an offset. Due to the misalignment of the two fibers, the input light from the SMF will induce the core mode and cladding mode of the PCF with different propagation velocities. These two modes are coupled back to the other SMF to form the interference spectrum due to the accumulated phase difference. We then place the PCF-based MZI into an erbium-doped fiber ring laser to form the fiber laser sensor. Compared with the spectrum of the PCF-based MZI, the lasing peak of the fiber laser sensor has high signal to noise ratio (40dB) and narrow 3-dB bandwidth (<1nm), which can enhance the sensing accuracy.
     We have demonstrated the sensing properties of our PCF-based MZI fiber laser sensor for temperature, bending curvature and surrounding refractive index. The temperature sensitivity of the PCF-based MZI fiber laser sensor is about 5pm/oC between 30oC to 150oC. As we increase the bending curvature from 0.6925m-1 to 3.096m-1, it is observed that the lasing wavelength is exponentially increased. In addition, the measured refractive-index sensitivity is about 52.35nm/RIU as the surrounding refractive index is varied from 1.3388 to 1.3638. As a result, our proposed PCF-based MZI fiber laser sensors can be utilized as useful sensors which have high signal to noise ratio and narrow 3-dB bandwidth to enhance the sensing accuracy.
    Advisory Committee
  • Hung-wen Chang - chair
  • Yung-Jr Hung - co-chair
  • Jui-Yang Feng - co-chair
  • Chin-Ping Yu - advisor
  • Files
  • etd-0623115-001116.pdf
  • Indicate in-campus at 2 year and off-campus access at 2 year.
    Date of Submission 2015-07-23

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