• Journal of Sensor Science and Technology
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• v.9 no.1
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• pp.15-21
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• 2000

Optical fiber temperature sensor, using resonance wavelength shifting of single mode fiber-to-planar waveguide coupler by heat, was fabricated. Thermo-optic polymers, have large change of refractive index due to heat, were used for planar waveguide. The device fabrication procedure including fiber polishing steps was illustrated and the device structure with independent polarization was demonstrated experimentally. The resonance wavelength difference of fabricated device was less than 2nm. The resonance wavelength shifting owing to temperature variation, from room temperature($24^{\circ}C$) to $90^{\circ}C$, was showed $-0.54nm/^{\circ}C$, $-3nm/^{\circ}C$.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.163-170
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• 1997

The MgO-doped LiNbO$_3$ single crystals were grown along c-axis by the Czochralski method with the pulling rate of 3mm/h and the rotation of 10rpm. The MgO contents were form 1 to 4 mole%. The SHG properties were investigated with the pulsed Nd:YAG laser, and thermo-optic coefficient, electro-optic coefficient of birefringence and curie temperature were measured. Phase matching temperature and Curie temperature increase similarly with MgO content until 4 mole%.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.252-253
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• 2000

본 논문은 광통신 파장(1.3$mu extrm{m}$)에서 측면 연마된 광섬유와 열광학 평면도파로 결합기의 온도변화에 따른 광의 세기변화를 이용한 광섬유형 온도센서에 관한 연구이다. 본 연구에서 제안된 소자는 광통신영역에서 변화를 가지기 때문에 원거리 측정이 가능하고 열광학 평면도파로의 물질의 선택과 소자의 구조에 따라 넓은 온도감지 범위와 높은 분해능을 가지는 소자의 구현이 가능하다. (중략)

• ETRI Journal
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• v.27 no.1
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• pp.122-125
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• 2005

A polymer-based planar-lightwave-circuit-type variable optical attenuator (VOA) was fabricated using a hot embossing process. With an optimized one-step embossing process, forty micro-channels for the guidance of light were defined on a polymer thin film with an accuracy of ${\pm}0.5{\mu}m$. The fabricated polymeric thermo-optic VOA shows 30 dB attenuation with 110 mW electrical input power at $1.55{\mu}m$. The rise and fall times are less than 5 ms.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.192-193
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• 2002

지금까지 측면이 코어 가까이 연마된 잔일모드 광섬유와 평면 도파로 사이의 광결합을 이용한 소자들이 많이 연구되고 있다. 이를 이용한 소자들로는 광필터, 광변조기, 광스위치, 굴절계, 편광기 등이 있으며 최근에는 파장분할다중화(WDM)에서 인접채널간의 채널분리를 위한 소자로서 빗살필터의 연구 또한 활발히 이루어지고 있다. 이에 본 논문에서는 측면이 코어 가까이 연마된 단일모드 광섬유와 평면도파로 사이의 광결합을 이용한 빗살필터를 제작하였으며 열광학 효과를 이용하여 파장 가변 빗살 필터를 구현해 보았다. (중략)

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.253-256
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• 2000

We report the experimental results for the coupling properties of the an side-polished single-mode fiber covered with metal-clad planar waveguide. The experimental results show that the large birefringence of a metal-clad planar waveguide facilitates the effective separation of TE and TM polarization in the spectral domain. Additionally the resonant wavelengths of the device are tuned based in the thermo-optic effect of polymer planar waveguide.

• Journal of Sensor Science and Technology
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• v.26 no.5
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• pp.338-341
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• 2017

We have investigated a temperature sensor on a thermal expansion effect of a fused optical fiber coupler. Both side of the fused tapered region of the coupler were fixed on a metal support to induce the high thermal expansion effect. The sensor showed that the peak coupling wavelengths were shifted to shorted wavelength region with increased of environmental temperature. The sensitivity of the sensor was $0.12nm/^{\circ}C$.

• Journal of the Korean Society for Nondestructive Testing
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• v.10 no.2
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• pp.50-55
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• 1990

Flaws in GFRP(Glass Fiber Reinforced Plastics) were thermally detected using cholesteric liquid crystals. Presence of flaws changes the thermal conductivity of GFRP, and disturbs heat flow. When a uniform heat source is applied, the surface temperature of flawed region is different from that of sound region. The surface temperature distributions were measured by thermo-optic properties of liquid crystal. Since the colors of liquid crystal indicate temperature distribution of GFRP surface, the thermal disturbance by flaws could be detected. The locations of flaws in GFRP could be determined from the distribution of liquid crystal colors.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.114-115
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• 2003

최근 급속히 성장하고 있는 Wavelength-division-multiplexing (WDM) 시스템에 파장가변 필터는 핵심적인 소자로 적용될 수 있으며, 높은 가격 경쟁력과 광학 필터로서 좋은 특성과 높은 가변 특성을 구현할 수 있다. 이러한 파장가변 필터는 multi-beam 간섭을 이용하고, Micro electro mechanical systems (MEMS) 공정 기술인 벌크 마이크로 머시닝 기술을 이용하여 구현되어지고 있다. 또한 파장 가변 필터는 Optical-performance monitoring, Spectrometer, Optical noise filter, Sensor 등 여러 분야에 응용될 수 있다. (중략)

• Korean Journal of Optics and Photonics
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• v.17 no.4
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• pp.371-380
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• 2006

We design and fabricate a novel tunable wavelength filter, which utilizes long-range surface plasmon-polaritons excited along nm-thick-metal strips. A gold metal strip, with $\sim$ cm length, 20 nm thickness, and $\sim$ 5$\mu$m width, is embedded in thick thermo-optic Polymer films supported by a silicon wafer. A dielectric Bragg grating structure is Placed on the metal strip, so that transmission signals at telecom wavelength are selected by thermal effect of the thermo-optic polymer. High extinction ratio of 25 dB and total insertion loss of $\sim$25 dB/cm can be measured by single-mode coupling of optical fibers. We also verify that wavelength tuning of the long-range surface plasmon-polariton filters can be achieved by electric current directly applied to the metal-strip waveguides.