• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1503-1507
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• 2004

New synthetic methodology of the saturated and unsaturated Er(III)-chelated prototype complexes based on benzoate and pentafluorobenzoate ligands was developed through ligand-exchange reaction. The saturated 8-coordinated Er(III) complexes exhibit stronger near-IR emission than those of the unsaturated 6-coordinated Er(III) complexes, obtained from the direct photoexcitation of Er ions with 488 nm. Three $H_2O$ molecules coordinated in the unsaturated 6-coordinated complexes seriously quenched the near IR emission by the harmonic vibration relaxation decay of O-H bonds. Also, the stronger emission of the Er(III) complexes was obtained by the indirect photoexcitation of ligands than by the direct photoexcitation of the Er(III) ions, due to the energy transfer between the excited ligand and the erbium ion. Furthermore, the saturated Er(III)-chelated complex with C-F bonds shows much stronger near IR emission than that of the saturated Er(III)-chelated complex with C-H bonds. It is attributed to the influence of C-F bonds on near IR emission.

• Korean Journal of Optics and Photonics
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• v.20 no.5
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• pp.266-271
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• 2009

We designed a thermo-optic switch based on a directional coupler with not only a high extinction ratio but also significantly low power consumption. The switch operates by using the thermo-optic effect of the polymer which the refractive index changes by heating the electrode. If the electrode is not powered (OFF), the input light will be coupled completely to the other waveguide. When the electrode is powered at a certain level (ON), input light launched into the input waveguide will remain in that waveguide due to the lower index adjusted in the other waveguide. The switch based on the directional coupler was designed using the generalized extinction ratio curve and the lateral shift of the input waveguide. The coupling length is 1,610 ${\mu}m$ and the extinction ratios are -28 and -30 dB for ON and OFF states, respectively. The electrode structures were optimized by thermal analysis. The transported heat into the waveguide is increased, as the electrode width (w) is increased and the center distance between the electrode and the waveguide (d) is decreased. Also, because the heat generated in the electrode affects the other waveguide, the temperature difference between two waveguides is varied as the given w and d. There are specific conditions which have the maximum of the temperature difference. That of the temperature difference is increased as the width and the temperature of the electrode are increased. Especially, when the switch is designed using the condition with the maximum of the temperature difference for switching, the temperature of the electrode can be decreased. We expect this condition will be the novel method for the reduction of the power consumption in a thermo-optic switch.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2000.04a
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• pp.19-25
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• 2000

Dielectric polymer films produced from benzocyclobutene (BCB) formulations (CYCLOTENE＊ family resins) are known to possess many desirable properties for microelectronic applications; for example, low dielectric constant and dissipation factor, low moisture absorption, rapid curing on hot plate without reaction by-products, minimum shrinkage in curing process, and no Cu migration issues. Recently, BCB-based products for thick film applications have been developed, which exhibited excellent dissipation factor and dielectric constant well into the GHz range, 0.002 and 2.50, respectively. Derived from these properties, the applications are developed in: bumping/wafer level packaging, Ga/As chip ILD, optical waveguide, flat panel display, and lately in BCB-coated Cu foil for build-up board. In this paper, we review the relevant properties of BCB, then the application areas in bumping/wafer level packaging and BCB-coated Cu foil for build-up board.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.186-187
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• 2002

광통신의 최종 목적은 각 가정까지 광섬유를 연결하여 일반인들도 많은 정보를 신속하고 쉽게 접할 수 있게 하는 것, 즉, 광가입자망(Fiber To The Home, FTTH)의 실현이라고 할 수 있다. 그러나 여러 가지 문제점으로 인해 아직까지는 일부 실험 지역 내에 국한되어 있다. 광가입자망의 실현을 위한 이론적 방법으로 광섬유를 정보 전달소에서 각 가정까지 직접 연결하는 것이 있으나, 이 방법은 경제적 면에서 경쟁력을 갖출 수 없을 뿐 아니라 물리적인 부피 증가로 인해 현실적으로 실현 불가능하다고 할 수 있다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.292-295
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• 2005

Variable optical attenuators (VOA) made of low-loss fluorinated polymers are demonstrated which shows a low operating power less than 30 mW due to the superior thermo-optic effect of polymer material and a low insertion loss less than 1.0 dB by incorporating highly fluorinated polymers to reduce the absorption loss at 1550 nm. An attenuator-integrated low-crosstalk polymeric digital optical switch (DOS) is also demonstrated. The switch and attenuator shares a single connected electrode which is controlled by a single current source. Due to the simple structure of the integrated attenuator, the device length is reduced to 1 cm so as to provide low insertion loss of 0.8 and 1.1 dB for 1300 and 1550 nm, respectively. The attenuator radiates remained optical signal on the switch-off branch in order to decrease the switching crosstalk to be less than -70 dB with an applied electrical power of 200 mW.

• 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)

• Korean Journal of Optics and Photonics
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• v.15 no.3
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• pp.222-228
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• 2004

The variable optical attenuator based on side polished fiber technique was experimentally demonstrated. Various combination mixtures of poly(vinylidene fluoride) and poly(methyl methacrylate) have been used as the overlay waveguide materials for the variable optical attenuator application. A controllable amount of optical power can be extracted via evanescent coupling by changing the temperature of the polymer mixture, thereby changing its refractive index. The VOA under test provides a maximum attenuation of 30 ㏈ and an insertion loss of 0.1 ㏈.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.12-13
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• 2000

광섬유형 센서는 전자기 간섭에 강하고 높은 감도와 원거리측정 등의 장점이 있어 이에 대한 연구가 활발하게 진행되고 있다. 온도센서의 경우 다양한 구조의 센서 구현이 용이하고 넓은 온도범위에서의 측정이 가능하다. 하지만 이러한 광섬유형센서는 대부분 온도변화를 물리량의 변화로 감지하기 때문에 작은 온도의 감지에는 구조적인 한계를 가지는 경우가 많으며 이러한 문제점을 개선하기 위하여 많은 연구가 시도되고 있다$^{[1]}$ . 본 논문은 이러한 점을 인지한 측면연마된 광섬유와 평면도파로 결합기형 고감도 온도센서에 관한 연구이다. 본 연구에서는 온도의 감지를 열광학 평면도파로의 열광학계수에 의존하기 때문에 물질의 변화에 따라 다양한 온도감도 조절과 높은 분해능을 가지는 센서의 구현이 가능하다. (중략)

• ETRI Journal
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• v.41 no.2
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• pp.262-269
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• 2019

This paper introduces a low-cost, high-performance mmWave antenna array module at 77 GHz. Conventional waveguide transitions have been replaced by 3D CPW-microstrip transitions which are much simpler to realize. They are compatible with low-cost substrate fabrication processes, allowing easy integration of ICs in 3D multi-chip modules. An antenna array is designed and implemented using multilayer coupled-fed patch antenna technology. The proposed $16{\times}16$ array antenna has a fractional bandwidth of 8.4% (6.5 GHz) and a 23.6-dBi realized gain at 77 GHz.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.4
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• pp.19-22
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• 2017

In this study, wavelength-free $1{\times}N$ optical splitter using a tapered polymer waveguide was studied to realize the transmission network of high-speed information communication network. Based on the evaluation of mode converting characteristics of splitter having two tapered multi-mode interference structures, an optimized structure of the $1{\times}N$ splitter was proposed for wide-range of input wavelength. 2D-BPM analysis $1{\times}8$ model showed that insertion loss of the proposed splitter is less than 10 dB for wavelength of input source from 1260 nm to 1650 nm.