• 세라미스트
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• 제10권3호
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• pp.75-85
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• 2007

Over the past few years, due to the great development of optical communications, an increasing R&D activity has been focused on the design and manufacture of the integrated optic amplifiers, with particular reference to their application in wavelength-division-multiplexing (WDM) systems. In this technological context, rare-earth-doped oxide glasses, which had been widely used for solid state lasers, gained much attention as highly performing materials in the third telecom window, around 1.5 micron. The aim of the present paper is to provide a brief overview of the progress made, with particular reference to the authors' work in this area, and to shortly discuss its perspectives.

• 한국광학회지
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• 제22권6호
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• pp.276-282
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• 2011

펨토초 펄스형 자발적 매개하향변환에서 생성된 1.5 ${\mu}m$ 통신파장대역 광자쌍의 진동수 얽힘상태를 구현하고, 광섬유 기반 Hong-Ou-Mandel 간섭계를 이용하여 양자간섭 실험을 수행하였다. 각진동수 ${\omega}_1$과 ${\omega}_2$에 대응하는 두 광자의 파장은 저밀도 파장분할다중화(coarse wavelength division multiplexing, CWDM) 필터를 이용하여 선택하였고, 간섭계에서 경로차에 따른 두 검출기의 동시계수 측정에서 높은 선명도를 갖는 공간적인 맥놀이 형태의 간섭무늬를 관측하였다.

• 대한기계학회논문집A
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• 제25권12호
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• pp.2100-2108
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• 2001

The impinging tones by high-speed plane jets are experimentally investigated to study the edgetone characteristics. Experiment used a slit nozzle and a wedge system to generate edgetones. The jet in the experiment is varied from low to high subsonic speed to obtain the effect of the speed on the frequency characteristics of impinging tones. The experimental data obtained previously fur edgetones and platetones by various nozzles are compared with the present edgetone data. And the condition of tone generation, the frequency ranges, the effective source point and the sound pressure level are compared and discussed. It is found that the jet speed has no diect influence on the impinging tone characteristics. Regardless of the jet speed, the effective source point is about a quarter wavelength downstream from the edge tip. With increase in jet speed, the influence of the nozzle configuration is decreased and the operating frequencies show good coincidences by normalized parameters based on the slit thickness.

• ETRI Journal
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• 제28권1호
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• pp.103-106
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• 2006

We have fabricated a planar lightwave circuit (PLC) hybrid-integrated optical sub-assembly of a triplexer using a thin film filter (TFF)-attached wavelength division multiplexer (WDM) and photodiode (PD) carriers. Two types of TFFs were attached to a diced side of a silica-terraced PLC platform, and the PD carriers with a $45^{\circ}$ mirror on which pin-PDs were bonded were assembled with the platform. A clear transmitter eye-pattern and minimum receiver sensitivity of -24.5 dBm were obtained under 1.25 Gb/s operation for digital applications, and a second-order inter-modulation distortion (IMD2) of -70 dBc was achieved for an analog receiver.

• Journal of the Optical Society of Korea
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• 제17권5호
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• pp.423-427
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• 2013

We present the preparation and characteristics of liquid-phase sensors based on nano-porous silicon multilayer structures for determination of organic content in gasoline. The principle of the sensor is a determination of the cavity-resonant wavelength shift caused by refractive index change of the nano-porous silicon multilayer cavity due to the interaction with liquids. We use the transfer matrix method (TMM) for the design and prediction of characteristics of microcavity sensors based on nano-porous silicon multilayer structures. The preparation process of the nano-porous silicon microcavity is based on electrochemical etching of single-crystal silicon substrates, which can exactly control the porosity and thickness of the porous silicon layers. The basic characteristics of sensors obtained by experimental measurements of the different liquids with known refractive indices are in good agreement with simulation calculations. The reversibility of liquid-phase sensors is confirmed by fast complete evaporation of organic solvents using a low vacuum pump. The nano-porous silicon microcavity sensors can be used to determine different kinds of organic fuel mixtures such as bio-fuel (E5), A92 added ethanol and methanol of different concentrations up to 15%.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.425-427
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• 1997

Ti:LiNbO$_3$optical waveguides were fabricated as a function of Ti thickness and pigtailed with polarization maintaining fiber(PMF). The near field patterns and total insertion loss of these sample was showed and measured for optical wavelength 1550nm. The fiber-to-waveguide coupling loss was described also .

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 추계학술대회
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• pp.711-713
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• 2017

본 논문에서는 800nm급 펨토초 레이저와 위상마스크를 이용하여 게르마늄이 첨가된 일반 광섬유(Corning SMF-28)에 FBG 센서를 가공하였다. 제작된 FBG 센서는 누적방사선 100 kGy급 감마선에 조사하여 방사선 영향을 평가하였다. fs-FBG-2 센서는 방사선 조사 중에 불완전한 광특성을 보였지만, fs-FBG-1 센서는 누적선량 100kGy에서 Bragg 파장변화가 10pm 이하로 나타나 뛰어난 내방사선 특성을 보였다.

• 인터넷정보학회논문지
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• 제14권2호
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• pp.45-51
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• 2013

본 논문에서는 자외선(UV, ultraviolet) 및 적외선(IR, infrared) 센서를 결합함으로서 불이 연소하면서 방출하는 빛의 파장을 활용한 영상신호를 검출하는 결합형 불꽃영상 검출시스템은 적외선 센서와 자외선 센서 기반의 신호처리 알고리즘 설계방안을 제안한다. 또한, 설계한 듀얼모드인 결합형 불꽃영상 검출시스템은 단독형 적외선 또는 자외선 센서 기반의 영상검출 알고리즘의 검출 성능결과를 비교한다.

• Current Optics and Photonics
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• 제5권4호
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• pp.458-465
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• 2021

Borate nonlinear optical crystals have been used as frequency conversion devices in many fields due to their unique transparency and nonlinearity from ultraviolet to visible spectral range. In this study, we theoretically and numerically investigate the properties of broadband second harmonic generation (SHG) in the recently reported Pna2₁-Ba₃Mg₃(BO₃)₃F₃ (BMBF) crystal. The technique is based on the simultaneous achievement of birefringence phase matching and group velocity matching between interacting waves. We discussed all factors required for broadband SHG in the BMBF in terms of two types of phase matching and group velocity matching conditions, the beam propagation direction and the corresponding effective nonlinearity and spatial walk-off, and the spectral responses. The results show that bandwidths calculated in the broadband SHG scheme are 220.90 nm (for Type I) and 165.85 nm (for Type II) in full-width-half-maximum (FWHM). The central wavelength in each case is 2047.76 nm for Type I and 1828.66 nm for Type II at room temperature. The results were compared with the non-broadband scheme at the telecom C-band.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.196-196
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• 2012

Graphene, two-dimensional one-atom-thick planar sheet of carbon atoms densely packed in a honeycomb crystal lattice, has grabbled appreciable attention due to its extraordinary mechanical, thermal, electrical, and optical properties. Based on the graphene's high carrier mobility, high frequency graphene field effect transistors have been developed. Graphene is useful for photonic components as well as for the applications in electronic devices. Graphene's unique optical properties allowed us to develop ultra wide-bandwidth optical modulator, photo-detector, and broadband polarizer. Graphene can support SPP-like surface wave because it is considered as a two-dimensional metal-like systems. The SPPs are associated with the coupling between collective oscillation of free electrons in the metal and electromagnetic waves. The charged free carriers in the graphene contribute to support the surface waves at the graphene-dielectric interface by coupling to the electromagnetic wave. In addition, graphene can control the surface waves because its charge carrier density is tunable by means of a chemical doping method, varying the Fermi level by applying gate bias voltage, and/or applying magnetic field. As an extended application of graphene in photonics, we investigated the characteristics of the graphene-based plasmonic waveguide for optical signal transmission. The graphene strips embedded in a dielectric are served as a high-frequency optical signal guiding medium. The TM polarization wave is transmitted 6 mm-long graphene waveguide with the averaged extinction ratio of 19 dB at the telecom wavelength of $1.31{\mu}m$. 2.5 Gbps data transmission was successfully accomplished with the graphene waveguide. Based on these experimental results, we concluded that the graphene-based plasmonic waveguide can be exploited further for development of next-generation integrated photonic circuits on a chip.