• Journal of Sensor Science and Technology
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• v.31 no.5
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• pp.353-359
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• 2022

This study investigated via computational analysis the application utility of series-cascaded ring resonators based on silicon-on-insulator (SOI) slot optical waveguides in integrated optical biochemical sensors. The radii of the two rings in the series-cascaded ring resonators were 59.4 ㎛ and 77.6 ㎛ respectively, and the coupling distance was 0.5 ㎛. The series-cascaded ring resonators were computationally analyzed using FIMMProp and PICWave numerical software. The free spectral range (FSR), full width at half maximum (FWHM), sensitivity, and quality-factor (Q-factor) of the series-cascaded ring resonators were 12.2 nm, 0.134 nm, 4100 nm/RIU, and 11580, respectively, and the measurement range was calculated to be slightly smaller than 3×10^-3 RIU. Although the measurement range was smaller than that of the single ring resonator, upon considering other characteristic parameters, the series-cascaded ring resonators are found to be more effective as integrated sensors than single ring resonators.

• Journal of the Optical Society of Korea
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• v.11 no.2
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• pp.55-58
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• 2007

We propose a systematic method for design of fiber-optic surface plasmon resonance (SPR) sensors. We used rigorous coupled wave analysis (RCWA) for analysis of the transmission spectrum, and the (1+1) evolution strategy (ES) was employed as an optimization tool. The simulation results show that the optimization method presented here is very useful in designing fiber-optic SPR sensor for strain and temperature measurement. This algorithm can be extended to another objective function with other weighting factors and optical parameters.

• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.397-402
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• 2022

In this short review, we explore the recent progress in metal-based gas-sensing techniques. The strong interaction between the metal films and hydrogen gas can be considered to play a considerably important role in the gas-sensing technique. The physical and chemical reactions in Pd-Pd hydride systems were studied in terms of the phase transition and lattice expansion of the metals. Two types of represented detection, electrical and optical, were introduced and discussed along with their advantages.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.6
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• pp.761-767
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• 2007

We have developed novel optical-fiber sensors based on strain-induced long-period fiber gratings for monitoring the deformation of a hull. They have no external pressure for sustaining the mechanical formed gratings. The pressure, which provides a force to form the periodic grating along the single mode fiber, was realized by the bonding strength of a photopolymer. To reduce the polarization dependency of the sensors caused by the asymmetry structure of gratings, a Faraday Rotator Mirror (FRM) was utilized in this experiment. We have realized the polarization-insensitive function of the proposed sensors. The change of an external strain are measured by an optical spectrum analyzer. When the external stain increases. the attenuation at the resonant wavelength decreases and the loss peak was slightly shifted to the shorter wavelength.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.3
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• pp.579-587
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• 1998

In this study, fatigue behavior of the optical fiber sensor embedded in composite laminate was investigated. Static tensile and fatigue tests were performed for three types of laminated composite specimens with embedded optical fiber sensor in the neutral plane ; [0/sub 6//OF/0/sub 6/]/sub T/, [0/sub 2//90/sub 4//OF/90/sub 4//0/sub 2/]/sub T/ and [0/sub 3//90/sub 3//OF/90/sub 3//0/sub 3/]/sub T/. The fracture of the embedded optical fiber sensor was detected by the intensity drop off of laser signal transmitted through the optical fiber sensors embedded within laminated composite specimen. The maximum fatigue stress applied to laminated specimen was compared with the average tensile stress at which the fracture of the embedded optical fiber within the laminate occurred under static tensile loading. From the experiments, firstly it is observed that the decrease in the life of optical fiber sensors embedded within unidirectional-ply laminate by the fatigue loading is relatively small compared to that of cross-ply laminate. Secondly, the optical fiber embedded in unidirectional-ply laminate is fractured by the fatigue damage due to the growth of internal defects of optical fiber, however the optical fiber embedded in cross-ply laminate is fractured by the growth of transverse matrix crack.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.766-768
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• 1998

Optical Temperature Distribution measurement System (OTDS) is completely different from conventional electric point sensor in that it uses the optical fiber itself as the sensor. This new concept in temperature measuring system requires only one fiber to be laid. The use of optical fiber also gives the advantage of small diameter, light weight, explosion resistance, and electromagnetic noise resistance. The OTDS is a sensor which is capable of making a precise measurement over a wide range of areas using only a single optical fiber. Since current temperature sensors, such as the thermocouple, are only used to measure temperaturea of point, they are almost impractical for measuring a wider range because of the extremely high cost. In comparision with current sensors, the optical fiber distributed temperature sensor can make much quicker and more precise measurements at a comparatively low cost.

• Journal of Sensor Science and Technology
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• v.22 no.4
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• pp.297-301
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• 2013

We proposed and demonstrated a distributed fiber-optic overheating detection sensor using optical time domain refrectometry. With increased of temperature the optical fiber is bended by a bi-metal and it result in optical leaky loss of the fiber. The sensor structure is designed in such a way that the signal of overheating is happen when the temperature exceeding a threshold temperature and the optical fiber is protected from excess bending.

• Journal of Sensor Science and Technology
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• v.32 no.1
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• pp.62-65
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• 2023

The wave mode calculation of a large-scale optical system in comparison to the working wavelength is practically impossible because the computational cost increases exponentially. In this paper, we propose a method that can obtain the optical mode in a large-scale optical system. The method carries out simulations by dividing the calculation area into blocks and moving along the light axis along which the light propagates. By applying this method to the calculation of resonant modes in a ring-type optical resonator, which is mainly used for ring laser optical gyro sensors, the efficiency of the proposed method was verified.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.586-592
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• 2016

This paper proposes a luminance compensation method using optical sensors to achieve high luminance uniformity of active matrix organic light-emitting diode (AMOLED) displays. The proposed method compensates for the non-uniformity of luminance by capturing the luminance of entire pixels and extracting the characteristic parameters. Data modulation using the extracted characteristic parameters is performed to improve luminance uniformity. In addition, memory size is optimized by selecting an optimal bit depth of the extracted characteristic parameters according to the trade-off between the required memory size and luminance uniformity. To verify the proposed compensation method with the optimized memory size, a 40-inch 1920×1080 AMOLED display with a target maximum luminance of 350 cd/m² is used. The proposed compensation method considering a 4σ range of luminance reduces luminance error from ± 38.64%, ± 36.32%, and ± 43.12% to ± 2.68%, ± 2.64%, and ± 2.76% for red, green, and blue colors, respectively. The optimal bit depth of each characteristic parameter is 6-bit and the total required memory size to achieve high luminance uniformity is 74.6 Mbits.

• Korean Journal of Optics and Photonics
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• v.21 no.4
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• pp.168-174
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• 2010

Fiber optic current sensors based on polarization-rotated reflection interferometry are demonstrated by incorporating them into polymeric optical waveguide components, including polarization-maintaining 3-dB couplers, TE-pass waveguide polarizers, and thermooptic phase modulators. To remove the bending induced birefringence, optical fiber coil is annealed at $850^{\circ}C$ for 24 hours. The reflection interferometry comprising polymer waveguide devices exhibit a highly stable output signal corresponding to the flowing current.