• 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.

• 대한전자공학회논문지SD
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• 제37권6호
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• pp.64-71
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• 2000

등간격, 동일 구조의 $Ti:LiNbO_3$ 세 도파로를 이용한 광스위치를 설계하고 제작하였다. 공도파로는 z-cut $LiNbO_3$ 기판상에 Ti를 내부 확산시켜 제작하였다. TM 모드 전파 손실을 줄이기 위하여 도파로 위에 $SiO_2$ 박막을 증착시킨 후, 광스위칭을 위하여 CPW(Coplanar Waveguide)구조 Al 전극을 형성시켰다. 가운데 도파로에 입사된 ${\lambda}=1.3{\mu}m$ 광에 대하여 세 도파로가 대칭적으로 detuning 되도록 전계 인가시 광 스위칭이 일어남을 확인하였다.

• 한국전기전자재료학회논문지
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• 제11권5호
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• pp.400-406
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• 1998

We investigated the preparation and guided-mode properties of $Ti:LiNbO_3$ waveguides which were fabricated by Ti in-diffusion. The diffusion method to reduce the Li out-diffusion was proposed. The optical guided-mode and propagation loss based on butt-coupling pigtailed with PMF-input were measured. How to improve the polishing grade of waveguide endfaces is newly proposed in this paper. To show the mode propagations, the BPM simulations of channel waveguide are described.

• Journal of the Optical Society of Korea
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• 제8권2호
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• pp.90-95
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• 2004

The structure of Ti:LiNbO$_3$optical waveguide with a mode size far different from that of single mode optical fiber has been optimized by tapering the waveguide ends. This work was focused on determining the optimized sets of parameters for the fabrication of low-loss Ti indiffused optical waveguides in LiNbO$_3$. Numerical and analytical modeling were applied to simulate the guiding quality and to determine the mode sizes. Based on these modeling results, new waveguide structures with tapered ends have been defined, fabricated and characterized in the respect of the coupling of fiber to Ti-indiffused LiNbO$_3$waveguide.

• E2M - 전기 전자와 첨단 소재
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• 제10권7호
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• pp.682-691
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• 1997

We have investigated the guided optical properties of a Ti:LiNbO$_3$optical waveguide which was fabricated by Ti-diffusion in an air atmosphere and proposed an effective polishing method of waveguide endfaces. And the results of guided optical mode and fabrication condition were obtained as follows; \circled1 propagation loss : 0.53 dB/cm \circled2 mode size : horizontal/vertical=12.5${\mu}{\textrm}{m}$ \circled3 mode mismatch : 1.7 dB \circled4 diffusion temperature : 105$0^{\circ}C$, time : 8 hours \circled5 atmosphere : air

• 한국광학회지
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• 제2권3호
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• pp.149-152
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• 1991

리튬나이오베이트 결정에 Ti를 열확산시켜 광도파로를 만드는 방법에서 문제가 되는 out-diffusion(삼출) 문제를 해결하는 방안으로 확산과정 이전에 $SiO_2$ 박막을 시료 위해 입히고 Ti을 열확산시켜 광도파로를 제조하는 방법을 제안하였으며, 기존의 방법에 의해서 만들어진 광도파로와 본 연구의 방법에 의해서 만든 광도파로의 근시야상(near field pattern)을 비교하였다.

• 한국결정성장학회지
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• 제1권1호
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• pp.1-4
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• 1991

The applicability of $LiNbO_{3}$ as a substrate for fabrication of Ti-indiffused waveguide electro-optic devices is limited. Ti diffuses comparatively in congruently melting $LiNbO_{3}$; the Curie temperature of this material is too low to permit diffusion temperatures much above $1100^{\circ}C$ without the necessity of re-poling the crystal. Both of hese difficulties could be eliminated by incorporating certain dopants in $LiNbO_{3}$. Crystals of $LiNbO_{3}$ doped with Ti and Mg were grown and evaluated. The electroptic coefficients and birefringence of $LiNbO_{3}$ doped crystals were measured at ${\lambda}=.6328$ and $1.32\;$\mu{m}$. Curie temperatures were measured. The Curie temperature of both undoped and Ti-doped $LiNbO_{3}$ was $1130^{\circ}C$; that for Mg-doped $LiNbO_{3}$ was $30^{\circ}$ higher. From these data, a composition for the crystals was estimated. Thermogravimetric data confirmed this estimate and showed that the composition of Mg : $LiNbO_{3}$ was $49.3{\pm}0.2mole%\;Li_{2}O$ ; the composition of the undoped and Ti : $LiNbO_{3}$ samples was $48.6{\pm}0.2mole%$. Diffusion of Ti into both Mg-doped and Ti-doped $LiNbO_{3}$ crystals was studied as a function of $Li/NbO_{3}$ ratio and temperature.

• 대한전자공학회논문지
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• 제26권10호
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• pp.1584-1590
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• 1989

In this study, a planar waveguide has been fabricated on a Y-cut LiNbO3 substrate by the Ti indiffusion technique and its guiding characteristics are measured by bright M-line spectroscopy. Using the photolithography method, an electro-optic grating modulator with interdigital electrodes has been fabricated by depositing Al on the Ti:LiNbO3 planar waveguide. And the beam intensity diffracted by the grating is measured as the applied voltage is increased.

• 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.

• 한국전기전자재료학회논문지
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• 제16권8호
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• pp.731-735
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• 2003

Ti-indiffused LiNbO$_3$waveguide have been used to various high speed optical device based on electro-optic effect such as modulators, switches, and sensor, etc. In order to high speed modulation of optical modulator have, one of the further devices, needed to increasing of electrode surrounding air by LiNbO$_3$dry etching because of impedance matching for optical and RF phase velocity between waveguide and electrode. We studied property of LiNbO$_3$dry etching after waveguide patterning lot optical modulation by using neutral loop discharge (NLD) plasma.