Dynamic Sensor Interrogation Using Wavelength-Swept Laser with a Polygon-Scanner-Based Wavelength Filter

Kwon, Yumi; Ko, Myeong Ock; Jung, Mi Sook; Park, Ik Gon; Kim, Namje; Han, Shihui; Ryu, Han-Cheol; Park, Kyung Hyun; Jeon, Min Yong

doi:10.3390/s130809669

Cited by 30 publications

(23 citation statements)

References 31 publications

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“…All these typologies of single- and multi-parameter OFS have interrogation based on spectral detection, which significantly differs from other approaches such as interferometry of intensity-based transducing [ 34 , 35 ]. Typical interrogation systems detect the spectrum reflected by the sensing structure on a wavelength interval ranging from 40 nm to 80 nm [ 36 , 37 , 38 , 39 ]. Most systems are based on a broadband light source and a spectrometer for detection [ 36 , 37 ].…”

Section: Introductionmentioning

confidence: 99%

Advanced Interrogation of Fiber-Optic Bragg Grating and Fabry-Perot Sensors with KLT Analysis

Tosi

2015

Sensors

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The Karhunen-Loeve Transform (KLT) is applied to accurate detection of optical fiber sensors in the spectral domain. By processing an optical spectrum, although coarsely sampled, through the KLT, and subsequently processing the obtained eigenvalues, it is possible to decode a plurality of optical sensor results. The KLT returns higher accuracy than other demodulation techniques, despite coarse sampling, and exhibits higher resilience to noise. Three case studies of KLT-based processing are presented, representing most of the current challenges in optical fiber sensing: (1) demodulation of individual sensors, such as Fiber Bragg Gratings (FBGs) and Fabry-Perot Interferometers (FPIs); (2) demodulation of dual (FBG/FPI) sensors; (3) application of reverse KLT to isolate different sensors operating on the same spectrum. A simulative outline is provided to demonstrate the KLT operation and estimate performance; a brief experimental section is also provided to validate accurate FBG and FPI decoding.

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Section: Introductionmentioning

confidence: 99%

Advanced Interrogation of Fiber-Optic Bragg Grating and Fabry-Perot Sensors with KLT Analysis

Tosi

2015

Sensors

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“…The bandwidth of the WSL is greater than that of the ASE from the SOA. The dotted box in the figure represents the polygon-scanner-based wavelength filter, which consists of a polygon rotating mirror, a diffraction grating, and two achromatic doublet lenses [12].…”

Section: Nematic Liquid Crystal Fabry-perot Etalonmentioning

confidence: 99%

Measurement of Effective Refractive Index of Nematic Liquid Crystal in Fabry-Perot Etalon

Ko¹,

Kim²,

Kim³

et al. 2015

Journal of the Optical Society of Korea

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We report a measurement of the effective refractive index of a nematic liquid crystal (NLC) inside a Fabry-Perot (FP) etalon according to the applied electric fields. The effective refractive index of the NLC depends on the intensity of the applied electric field. A wavelength-swept laser with a polygon-scanner-based wavelength filter is used as a wide-band optical source to measure the effective refractive index of the NLC. The bandwidth of the optical source is greater than 90 nm around 1300 nm. The fabricated NLC FP etalon consists of glass substrates, gold layers as the electrodes with highly reflective surfaces, polyimide layers as the planar alignment layers, and an LC layer. Furthermore, we measured the Freedericksz transition voltages for three types of NLC FP etalons having thicknesses of 30.6 μm, 55.4 μm, and 108.8 μm. The Freedericksz transition voltages in the three cases are nearly equal. The measured effective refractive indices in the three cases decreased from 1.67 to 1.51 as the applied electric field intensity was increased. Beyond the threshold electric field, the effective refractive indices quickly decreased and eventually saturated at a value of 1.51 for all cases.

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“…Another way is a swept source based on Fourier domain mode locking (FDML) technology, by introducing a several-kilometer single-mode fiber (SMF) in the cavity, meanwhile periodically driving the optical bandpass filter synchronously with the optical round-trip time of the light [8]. There are mainly four central wavelength swept sources, including 850 [9], 1050 [10][11][12], 1310 [4,8], and 1550 nm [13], used in the SSOCT system. It is demonstrated that SSOCT at the 1050 nm wavelength range is best for imaging in human retina and choroid layers, since the absorption of water at the 1050 nm range is lower than at the 1310 nm range, the scattering at the 1050 nm water window is reduced compared to that at 850 nm [10], and the dispersion of water near 1050 nm is zero [14].…”

Section: Introductionmentioning

confidence: 99%

Methods to improve the performance of the swept source at 10 μm based on a polygon scanner

Cao¹,

Wang²,

Zhang³

et al. 2017

Photon. Res.

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In this work, we investigate the methods to improve the performance of the swept source at 1.0 μm based on a polygon scanner, including in-cavity parameters and booster structures out of the cavity. The three in-cavity parameters are the cavity length, the rotating speed of the polygon scanner, and the in-cavity energy. With the decrease of cavity length, the spectrum bandwidth becomes wider and the duty cycle becomes higher. With the increase of the rotating speed of the polygon, the spectrum bandwidth becomes narrower, and the duty cycle becomes lower but the repetition rate becomes higher. With more energy in-cavity, the spectrum bandwidth becomes wider and the duty cycle becomes higher. The booster structures include the buffered structure, secondary amplifier, and dual-semiconductor optical amplifier configuration, which are used to increase the sweep frequency to 86 kHz, the output power to 18 mW, and the tuning bandwidth to 131 nm, respectively.

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Dynamic Sensor Interrogation Using Wavelength-Swept Laser with a Polygon-Scanner-Based Wavelength Filter

Cited by 30 publications

References 31 publications

Advanced Interrogation of Fiber-Optic Bragg Grating and Fabry-Perot Sensors with KLT Analysis

Advanced Interrogation of Fiber-Optic Bragg Grating and Fabry-Perot Sensors with KLT Analysis

Measurement of Effective Refractive Index of Nematic Liquid Crystal in Fabry-Perot Etalon

Methods to improve the performance of the swept source at 10 μm based on a polygon scanner

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