• 한국전기전자재료학회논문지
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• 제28권8호
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• pp.513-517
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• 2015

We proposed and demonstrated a simultaneous measurement method to detect the refractive index and temperature of a medium using a side-polished fiber involving FBG (fiber Bragg grating). The temperature of a medium was obtained by using the Bragg wavelength shift of FBG, while the refractive index of medium were calculated by using the transmission loss. The Bragg wavelength is independent on the refractive index of the covering medium placed on surface of side-polished fiber, while the transmission loss at off-Bragg wavelength highly depends on the environmental temperature because of thermo-optic effect of the medium.

• Journal of the Optical Society of Korea
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• 제12권3호
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• pp.166-169
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• 2008

The submersion monitoring system based on a reflective side-polished optical fiber submersion sensor with an optical fiber mirror was shown to be an effective alarm system with remote monitoringwhen the drainage capacity of a common utility duct is exceeded due to heavy rainfall. The proposed sensor was connected to an existing installed optical fiber network at a height of 250mm in a common utility duct, and then tested under sample materials(distilled water, river water, sea water, foul water, muddy water, petroleum, edible oil) at a distance of 1km from the sensor for remote sensing. In experiments, the proposed real-time sensor system reduced maintenance cost and improved monitoring efficiency by using a reflection-type side-polished optical fiber submersion sensor efficient for remote monitoring of a common utility duct.

• 센서학회지
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• 제19권6호
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• pp.428-434
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• 2010

In this study, a novel gas sensor based on evanescent field coupling between single mode side polished fiber and solvatochromic dye dispersed polymer waveguide was demonstrated. We fabricated a side polished optical fiber device as a volatile organic compounds gas detector. Solvatochromic dye was coated on the top of the side polished optical fiber to take advantage of evanescent field coupling. The solvatochromism can be defined as the phenomenon whereby a compound changes color, either by a change in the absorption or emission spectra of molecule, when reacted in different VOCs. The device reacted to polarity gases like a hexane, butane, xylene etc. The resonance wavelength was shifted by the xylene concentration which range was 0.1 ppm ~ 100 ppm. Also, the response with the concentration was lineer and the detection limit was 0.1 ppb.

• 센서학회지
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• 제32권1호
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• pp.51-54
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• 2023

We investigated a humidity sensor based on a polyimide-coated side-polished optical fiber. The polyimide film absorbed moisture, causing the resonant wavelength of the sensor to shift to a longer wavelength owing to the changes in the optical properties of the film. The experimental results showed that the resonant wavelength of the device shifted by 17-18 nm when relative humidity changed from 30% to 90%.

• 센서학회지
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• 제16권4호
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• pp.254-258
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• 2007

A novel cure sensor based on the side-polished single mode fiber has been proposed and demonstrated. Two different UV curable epoxies were used to verify the feasibility of the side-polished single mode fiber as a high sensitivity cure sensor. The volume change of the epoxy by UV curing results in a corresponding change of the refractive index. The sensor can be used to monitor the curing process, the refractive index variation and the volume change of epoxy in real time during the UV curing process. In addition, small birefringence of the epoxy film can be detected using the sensor.

• 센서학회지
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• 제14권4호
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• pp.286-290
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• 2005

We have demonstrated a refractometer for liquid based on a side-polished fiber. The device consists of a side-polished single mode fiber and a rectangular space which plays a role of the multimode planar waveguide when it is infused with a liquid. We presented a simple method to acquire the refractive index of a liquid by use of the spacings of periodic resonance wavelengths of the device. The resolution of the fabricated refractometer was order of $10^{-5}$

• Journal of the Optical Society of Korea
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• 제7권3호
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• pp.180-187
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• 2003

A theoretical presentation by using a three-dimensional finite difference beam propagating method (3-D FD-BPM) for the evanescent coupling is offered with respect to the refractive indexes between a side-polished optical fiber and an infinitely planar waveguide with a conductor cladding (PWGCC). The PWG is suspended at a constant distance from an unclad fiber core and attached with a perfect conductor (PEC) on one side. The coupling and propagation of light are found to depend on both the relationship between the refractive index values of two structures and the configuration of the side-polished fiber used in the PWGCC. The spreading of light in the unconfined direction of a PWGCC is presented with the distribution of electric fields in xy - plane and the absolute amplitude of electric fields along the x and y axis. The power of the light propagation in a fiber decreases exponentially along the fiber axis as it is transferred to the PWGCC, where it is carried away.

• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.337-341
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• 2010

A high sensitivity fiber optic temperature sensor based on a side-polished fiber (SPF) coupled to a tapered multimode overlay waveguide (MMOW) is proposed and studied. Both tapered and non-tapered MMOW were considered to study the effect of tapering of MMOW on the characteristics of the device and to investigate the criticality of the uniformity of the multimode overlay waveguide over the SPF. Present study shows that tapering of the MMOW can be used to tune the desired wavelength range without any loss in the sensitivity. Sensitivity up to 9 nm/$^{\circ}C$ within the temperature range of 25 to $100^{\circ}C$ can be achieved with the proposed sensor, almost 6 times higher compared even to state-of-the-art high-sensitivity grating-based fiber optic temperature sensors.

• 대한전자공학회논문지SD
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• 제40권9호
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• pp.651-657
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• 2003

얇은 중간 금속층을 가지는 측면 연마 광섬유 결합기를 이용한 편광분리기를 구현하였다. 실험 결과는 적절한 두께론 가지는 중간 금속층은 두 측면 연마된 광섬유 사이에서 TE 편광 성분의 광결합은 차단시키는 반면 TM 편광성분의 광결합은 허용함을 보여주었다. 측면 연마 광섬유를 이용한 편광분리기 설계 및 제작 기법을 기술하였다. 제작된 편광분리기는 TE와 TM 편광에 대하여 18dB와 23dB의 분리비를 보였다. 삽입손실은 TE 편광의 경우 0.7dB, TM 편광의 경우 1.3dB로 측정되었다.

• 대한전자공학회논문지SD
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• 제41권10호
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• pp.57-62
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• 2004

단일 모드 광섬유의 측면을 일부분 연마하여 연마된 상부에 열 광학 폴리머 층과 금속열선을 형성한 광섬유형 전류센서를 보고한다. 금속 열선에 인가된 전류에 의해서 발생하는 저항열은 폴리머 층의 굴절률을 변화시키고 광섬유의 소산장을 통한 광 감쇄를 유도하게 된다 두 가지 유형의 센서구조를 제안하였고 전류센서로서의 특징을 조사하였다.