• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.203-206
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• 2003

Thermo-optic tunable filter, with 4-pairs of H/L layers for DBR, was designed and fabricated. The transmittance characteristics of the filter were measured. Additionally, heating system and temperature sensor system were used in order to observe property of the filter by thermo-optic effect. The tuning efficiency of the filter was measured to be 0.144nm/K$^{-1}$ showing the tuning range of 9.4nm for the temperature variation of 64.7$^{\circ}C$. Filter, lens and fiber were aligned by micro-optical bench.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.2
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• pp.33-38
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• 2004

We have demonstrated a tunable Inter based on an asymmetric directional coupler made of a side-polished polarization maintaining fiber coupled with a polymer planar waveguide. The thermo-optic effects of the polymer planar waveguide induced by a micro-strip heater placed on the top layer of the device leads to shift of resonance wavelength of the coupler. The fabricated device exhibited wide tunable range exceeding 230 nm with 720 ㎽ of applied electrical power.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1097-1100
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• 2003

Tunable thermo-optic filter for WDM system was designed and fabricated. The basic structure of the filter was a Fabry-Perot resonator and the center cavity layer was poly-Si. Quardraple layers of low and high refractive index materials were used as DBR mirrors. Tuning and transmission efficiencies was measured and compared with the simulation results. Tuning range of 9.4 nm can be obtained by 64.7$^{\circ}C$ temperature changes and tuning efficiency was 0.144nm/K. The filter is to be assembled onto the micro optical bench with fiber optical path.

• Journal of IKEEE
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• v.12 no.3
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• pp.131-137
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• 2008

A silicon Fabry-Perot tunable thermo-optic filter for WDM using the thin film silicon coating is proposed and experimented. The filter is implemented by using the CMP process and polishing both sides of the commercial silicon wafer with normal thickness of 100${\mu}m{\pm}$1%. The filter also has 2-layer or 3-layer dielectrics thin film coating mirror which are alternated ${\lambda}$/4 layers of $SiO_2$($n_{low}$=1.44) and a-Si($n_{high}$=3.48) for the central wavelength of 1550nm by RF sputtering. The experiment shows that FSR is 3.61nm and FWHM is 0.56nm and the finesse is 6.4 for 2-layer mirror with the reflection of 61%, and that FSR is 3.36nm and FWHM is 0.13nm and the finesse is 25.5 for 3-layer mirror with the reflection of 89%. According to thermo-optic effect, the transmitted central wavelength of 1549.73nm at $23^{\circ}C$ is shifted to 1550.91nm at $30^{\circ}C$ and 1553.46nm at $60^{\circ}C$ for 2-layer mirror, and the transmitted central wavelength of 1549.83nm at $23^{\circ}C$ is shifted to 1550.92nm at $30^{\circ}C$ and 1553.07nm at $60^{\circ}C$ for 3-layer mirror.

• Korean Journal of Optics and Photonics
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• v.10 no.3
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• pp.248-253
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• 1999

In this paper, we have investigated a fiber type active coupler which utilizes the mode coupling between the side polished single mode optical fiber and the active multimode planar waveguide. The proposed device can be used for not only tunable wavelength filter or optical intensity modulator but also a tool for measuring optical properties of guiding material such as refractive index, birefringence, electro-optic coefficient, and thermo-optic coefficient. We gave designed and optimized a coupler structure using the BPM and fabricated the device using thermo-optic polymer as active planar waveguide overlay. The device showed that insertion loss was less then 0.5 dB, extinction ratio was -13 dB at the resonance wavelength, and the wavelength tunablity due to thermo-optic effect was -1.5 nm/$^{\circ}C$. The active coupler using thermo-optic effect can be used as a wavelength tunable filer, an optical intensity modulator and an optical sensor. pulses that are subsequently compressed by a dispersive optical fiber. Experimental results show that $sech^2$ shape pulses with a pulse width of ~14 ps and a time bandwidth product of ~0.34 are successfully generated at 10 GHz repetition rate. In contrast to other methods, such as higher order soliton compression, this approach does not depend on the optical power and thus shows promise for application to low-power lasers.

• 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.

• Korean Journal of Optics and Photonics
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• v.16 no.5
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• pp.401-405
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• 2005

In this paper, we have presented mechanically formed long-period fiber gratings using periodically arrayed brass wires with a $250-{\mu}m$ diameter and realized the function of current-controlled wavelength-tuning. With the thermo-optic effect of the surrounding medium around the fiber cladding, the continuous displacement of the resonance wavelengths is achieved through the resistant heat of the wire which changes the refractive index of surrounding material. The tunability for each mode as a function of an applied electrical power is investigated. When the glycerin is used as a thermo-optic material, the measured tuning ranges of $LP_{03}$ and $LP_{04}$ within electrical power of 20 W reach to 14 nm and 48 nm, respectively. The experimental results are in good agreement with the theoretical that which is analyzed by a geometric-optics approximation.

• 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)

• Korean Journal of Optics and Photonics
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• v.18 no.1
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• pp.79-83
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• 2007

A reconfigurable photonic microwave (MW) channel selective filter was demonstrated incorporating a $1{\times}2$ switch based on two tunable polymeric resonators with different free spectral ranges. Each resonator, consisting of two cascaded rings with an electrode formed on one of them, plays a role as an on/off switch through the thermooptic effect. The optical signal carrying the MW signal is routed to either port of the switch and detected to show the filtered output at the frequency determined by the free spectral range of the corresponding resonator. When the channel centered at 10 GHz was chosen, the extinction ratio was ${\sim}30dB$, the bandwidth 1 GHz, and the electrical power consumption 4.1 mW. For the other channel located at 20 GHz, we have achieved the extinction ratio of ${\sim}30dB$, the bandwidth of 2 GHz, and the required power of 8.0 mW. Finally the crosstalk between the selected and blocked channels was higher than 24 dB.