• Korean Journal of Optics and Photonics
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• v.19 no.4
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• pp.315-319
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• 2008

We investigate theoretically the power consumption of a notch filter using a thermo-optic long-period grating, which is induced by a heater array consisting of periodic heaters and pads made of metal thin-film. Since the power consumed by the heater array is converted to joule heat that generates the thermo-optic long-period grating, the characteristics of the notch filter are dynamically controlled by adjusting it. The power necessary for appropriate coupling efficiency depends on the parameters of the heater array, which are the width and length of a heater, pad width, and the thickness of the thin-film. We explain an approximate method of analyzing the influence of the parameters on the consumed power. Using the analysis method, we simulate the change of the power depending on the parameters. From the simulation, we suggest a few guidelines on the parameters required to reduce the power.

• ETRI Journal
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• v.33 no.2
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• pp.275-278
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• 2011

This letter presents a polymer $1{\times}2$ thermo-optic totalinternal-reflection digital optical switch (TIR-DOS) with an index contrast of 1.5%-${\delta}$ operating at low power consumption. The structure of our $1{\times}2$ TIR-DOS was created by adding a reflection port to that of a conventional multimode filtering variable optical attenuator. To improve the total-internalr-eflection efficiency, a heater offset was applied to the crossing region of multimode waveguides of the TIR-DOS. The fabricated $1{\times}2$ TIR-DOS shows a low electrical power consumption of 18 mW for an on-off ratio of 35 dB.

• 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.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.10
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• pp.57-62
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• 2004

We report the fiber-optic current sensors composed of a side-polished single-mode fiber with the thermo-optic Polymer layer and the metal wire as a heater. The index change of polymer layers caused by the resistant heat of the metal wires induces the optical attenuation through the evanescent field of the side-polished single-mode fiber. Two types of the sensors are proposed and their characteristics as a current sensor are investigated.

• Current Optics and Photonics
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• v.7 no.3
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• pp.254-262
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• 2023

Novel thermo-optically focus-switchable Fresnel zone plates based on phase-change metafilms are designed and analyzed at a visible wavelength (660 nm). By virtue of the large thermo-optic response of vanadium dioxide (VO₂) thin film, a phase-change material, four different plasmonic phase-change absorbers are numerically designed as actively tunable Gires-Tournois Al-VO₂ metafilms in two and three dimensions. The designed phase-change metafilm unit cells are used as the building blocks of actively focus-switchable Fresnel zone plates with strong focus switching contrast (40%, 83%) and high numerical apertures (1.52, 1.70). The Fresnel zone plates designed in two and three dimensions work as cylindrical and spherical lenses in reflection type, respectively. The coupling between the thermo-optic effect of VO₂ and localized plasmonic resonances in the Al nanostructures offer a large degree of freedom in design and high-contrast focus-switching performance based on largely tunable absorption resonances. The proposed method may have great potential in photothermal and electrothermal active optical devices for nonlinear optics, microscopy, 3D scanning, optical trapping, and holographic displays over a wide spectral range including the visible and infrared regimes.

• Proceedings of the Optical Society of Korea Conference
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• 1999.08a
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• pp.106-107
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• 1999

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.1
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• pp.153-158
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• 2009

Stable and tunable dual-wavelength erbium-doped fiber ring laser(EDFL) using a single fiber Bragg grating(FBG) and two coil heaters is proposed and demonstrated. Installing two identical coils into a single FBG, the FBG is symmetrically divided into two different portions. While a current supply to the coil, the refractive index of the FBG under the coil is changed. The FBG can operate as a joint of two different FBGs. Due to the thermo-optic effect of a fiber, the resonance wavelength split into two peaks. The spacing between two adjacent channels was changed as much as the difference of heating power. It was tuned up to 3 nm of wavelength under the electrical power with a 1000 mW. Moreover, the lasing wavelength can be individually tuned without influencing to the adjacent channel.

• ETRI Journal
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• v.30 no.5
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• pp.744-746
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• 2008

This letter presents a crosstalk-enhanced polymer thermo-optic digital optical switch operating at a low power consumption. Modified radiation-type attenuators are integrated in a series with a conventional $1{\times}2$ digital optical switch. A low optical crosstalk of less than -45 dB is attained at a low applied switching power of 60 mW, and an insertion loss of about 1.1 dB is exhibited.

• 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 the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.8
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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.