• 한국광학회지
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• 제13권1호
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• pp.32-37
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• 2002

두 모드 간섭 현상을 기초로 해서 1.55 $\mu\textrm{m}$ 파장대역에서 동작하는 편광모드 분리기를 Ti: x-cut LiNbO$_3$광도파로 구조를 이용하여 설계, 제작한 다음, TE, TM 입사 모드에 따른 소자의 동작 특성을 측정하였다. 광도파로 폭, 분기각도와 간섭영역 길이를 8$\mu\textrm{m}$, 0.55$^{\circ}$, 470$\mu\textrm{m}$로 제작된 소자의 분리 비는 TE, TM 입사 모드 각각에 대해서 16.18 dB, 21.25 dB로 측정되었으며, 누화는 -16.28 dB, -21.28 dB로 측정되었다. 삽입 손실은 TE, TM 각각에 대하여 2.24 dB/cm, 2.41 dB/cm로 측정되었으며. 30 nm 파장 범위 내에서 비교적 균일한 분리 비가 관찰되었다.

• 한국광학회지
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• 제17권5호
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• pp.430-436
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• 2006

1550nm 파장대역에서 편광에 관계없이 동작하는 $Ti:LiNbO_3\;2{\times}2$ 삽입/분기 광 멀티플렉서를 구현하였다. 소자는 두 개의 입 출력 광도파로, 두 개의 편광모드분리기, 두 개의 편광모드 변환기 그리고 전기광학효과로 파장을 가변시킬 수 있는 전극으로 구성되었다. TE, TM 편광에 대해서 단일모드 특성을 갖는 채널 광도파로는 x-cut $LiNbO_3$에 Ti 확산 방법으로 제작하였으며, 채널 광도파로 위에 배열된 $SiO_2$ 패드의 전단 스트레인을 이용하여 위상정합 편광모드변환기를 구현하였다. 한편 전기광학효과를 이용하여 파장을 가변시키기 위해서 전압을 인가하여 광도파로의 복 굴절률을 변화시켰다. 0.094nm/V 파장가변률과 최대 17nm 파장을 가변시켰으며, 8.2dB 부 모드레벨과 3.72nm FWHM을 측정하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.73-76
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• 1997

A low loss x-cut LiNbO$_3$ optical waveguide was fabricated by Ti in-diffusion and the guided-mode properties and total insertion loss of pigtailing with polarization maintaining fiber(PMF) were investigated and measured at optical wavelength 15507. For formaing the waveguide, the parameters of diffusion Ti thickness, waveguide line-width, length, diffusion temperature, time and atmosphere were set 1400$\AA$, 8${\mu}{\textrm}{m}$, 3.3cm, 105$0^{\circ}C$, 8 hours and wet bubbled oxygen, respectively. and then After the polishing and pigtailing, it showed that total insertion loss was -4.1dB for TM mode, -5.5dB for TE mode, and mode size, that is, horizontal/vertical sizes were 13.87/18${\mu}{\textrm}{m}$ for TM mode, 9.61${\mu}{\textrm}{m}$/6.5${\mu}{\textrm}{m}$ for TE mode.

• 전자공학회논문지D
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• 제35D권7호
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• pp.109-116
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• 1998

In this work was produced and analyzed a z-cut Ti:LiNbO$_{3}$ optical waveguide which applies for various optical devices.A waveguide channel with a thickness 8 .mu.m and a length 66,000.mu.m and a mach-zehnder interferometer type waveguide were fabricated at a diffusion temperature 1050.deg. C for 6-8hours in a wet $O_{2}$ environment. The resulting Ti:LiNbO$_{3}$ optical waveguide was measured to have a Ti-strip thickness of 950.angs. and low loss. Surfaces and cross-sections of a fabricated waveguide were analysed. The mode pattern anaysis revealed that the waveguide showed a single mode at a 1550nm wavelength. The effective dimension of the waveguide was calculated by measuring a gaussian profile; Wx=10.95.mu. and Wy=9.14.mu.m. a propagation loss, of 0.50dB/cm for a TM mode and 0.45dB/cm for a TE mode, was low enough to be accepatable for optical devices.

• 한국전기전자재료학회논문지
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• 제11권7호
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• pp.557-564
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• 1998

A low loss x-cut $LiNbO_3$optical waveguide was fabricated by Yi in-diffusion, and the properties of guided-mode and the total insertion loss of the pigtailed waveguide with polarization maintaining fiber(PMF) were measured at optical wavelength 1550nm. for forming the waveguides, the parameters of diffusion, Ti thickness, waveguide line-width, length, diffusion temperature, time and atmosphere were set $1400{\AA}$, $8{\mu}m$, 3.3cm, $1050^{\circ}C$, 8 hours and wet bubbled oxygen, respectively. And then after the polishing and piatailing, it showed that the total insertion loss was -4.1dB for TM mode, -5.5dB for TE mode, and mode size, that is, the horizontal/ vertical size were $13.8{\mu}m/18{\mu}m$ for TM mode, $9.6{\mu}m/6.5{\mu}m$ for TE mode.

• Journal of Electrical Engineering and Technology
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• 제6권2호
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• pp.263-269
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• 2011

In this study, the compositions for the microwave dielectric materials were investigated to obtain the improved dielectric properties, the high temperature stability, and the sintering temperature of less than $900^{\circ}C$, which was necessary for cofiring with the internal conductor of silver. In addition, the dielectric sheets were prepared by the tape casting technique, after which the sheets were laminated and sintered. In this process, the optimum ratio of powder and binder, laminating pressure, temperature, and possibility for cofiring with the internal conductor were studied. Finally, multilayer chip treplexer filter for the 800-2,000 MHz range were fabricated, and the frequency characteristics of the triplexer filter were investigated. When the $0.6TiTe_3O_8-0.4MgTiO_3+3wt%SnO+7wt%H_3BO_3$ ceramics were sintered at $820^{\circ}C$ for 0.3 hours, the microwave dielectric properties of the dielectric constant of 29.91, quality factor of 33,000 GHz, and temperature coefficient of resonant frequency of -2.76 ppm/$^{\circ}C$ were obtained. Using the Advanced Design System (ADS) and High Frequency Structure Simulator (HFSS), the multilayer chip triplexer filter acting at the range of 800-2,000 MHz were simulated and manufactured. The manufactured triplexer filter had the excellent frequency properties in the CDAM800, GPS and PCS frequency regions, respectively.

• 태양에너지
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• 제10권3호
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• pp.53-59
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• 1990

음극 전착법에 의해서 $CdSe_xTe_{1-x}$ 박막을 제작하고 그 결정구조를 조사하였다. 전착 전위 -0.45V vs.Ag/AgCl 근처에서 몰비 x값에 관계없이 일정한 한계전류가 나타났으며, 생성박막은 몰비 $x=0{\sim}0.8$ 범위에서 cubic zinc-blonde 구조이었으며 x=1에서 hexagonal wurtzite 구조이었다.

• 대한전자공학회논문지SD
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• 제39권1호
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• pp.58-66
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• 2002

Tapered 방향성 가중 결합 음향파 도파로를 이용하여 음향광학형 파장가변 광 필터를 LiNbO₃와 Ti 이중 확산 공정 기술을 이용하여 제작하였다. 1551.1㎚ 파장의 TE, TM 입사 편광모드와 173.58㎒ 35㎽ RF구동 신호에 대해서 각각 -14.29㏈, -14.99㏈ 부 모드 억압과 61%, 86% 변환효율이 측정되었다. 파장변화율과 통과 대역폭은 8.6㎚/㎒ 1.8㎚로 측정되었으며, 스위칭 속도는 2.82㎲로 측정되었다. 2.5㎚ 채널 간격에 대해서 약 -l4㏈누화 레벨이 측정되었으며, 부 모드와 채널 간격이 누화에 매우 큰 영향을 미치고있음을 확인하였다.

• 한국전기전자재료학회논문지
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• 제11권2호
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• pp.146-153
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• 1998

The optical near-field patterns, propagation loss and mode sizes of x-cut $Ti:LiNbO_3$ optical waveguide which was fabricated by Ti-diffusion varying with Ti strip thickness in wet oxygen atmosphere were discussed at optical wavelength 1550nm. As Ti thickness increased from $760{\AA}$, the insertion loss of waveguide was decreased. But at Ti thickness $1500{\AA}$, mode sizes are widely broadened. The Ti thickness of below $1100{\AA}$ and above $1500{\AA}$ showed negative effects to propagation loss and fiber coupling. The best Ti thickness for fabricating low propagation loss and good fiber coupling was inferred to be between $1100{\AA}-1500{\AA}$ in our conditions. And for Ti thickness $1150{\AA}$, its propagation loss, horizontal/vertical mode sizes were showed 1.61 dB/cm, $11.9/8.9{\mu}m$ for TM, 0.22 dB/cm, $12.0/9.1{\mu}m$ for TE respectively.

• Journal of the Optical Society of Korea
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• 제6권2호
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• pp.27-32
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• 2002

An integrated optical 2$\times$2 add/drop multiplexer in X-cut, Y-propagating LiNbO$_3$ has been demonstrated. The device consists of passive polarization splitters and acousto-optical mode converters with weighted coupling utilizing tapered acoustical directional couplers; their specific design and properties are discussed. The insertion loss has been measured to be about -8.16 ㏈ and -8.6 ㏈ for TE and TM polarizations, respectively. The device shows a 3 ㏈ bandwidth of 2.3 nm, a tuning rate 8.34 nm/MHz around λ = 1554 nm, and a sidelobe suppression of about 14.5 ㏈. Optimum operation is achieved with a RF drive power of about 43 ㎽. Multi-wavelength operation has been demonstrated.