• Journal of applied mathematics & informatics
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• 제30권1_2호
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• pp.253-264
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• 2012

In the present article, we construct the exact traveling wave solutions of nonlinear PDEs in the mathematical physics via the (1+1)-dimensional Boussinesq equation by using the following two methods: (i) A further improved ($\frac{G}{G}$) - expansion method, where $G=G({\xi})$ satisfies the auxiliary ordinary differential equation $[G^{\prime}({\xi})]^2=aG^2({\xi})+bG^4({\xi})+cG^6({\xi})$, where ${\xi}=x-Vt$ while $a$, $b$, $c$ and $V$ are constants. (ii) The well known extended tanh-function method. We show that some of the exact solutions obtained by these two methods are equivalent. Note that the first method (i) has not been used by anyone before which gives more exact solutions than the second method (ii).

• 한국광학회지
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• 제7권1호
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• pp.77-86
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• 1996

$Ti:LiNbO_3$ Mach-Zehnder 진행파형 광변조기의 CPW(coplanar waveguide) 전극구조, 특히 taper영역을 해석하기 위해서 SOR(successive over relaxation)법을 이용하였다. 변조기의 taper영역에서는 임피던스 정합, 즉 $Z_c 가 50\omega$이 만족되는 전극구조를 설계하였다. 변조기의 변조영역에서는 $Z_c=50\omega, n$$Z_c$ c/=50.OMEGA., n=2.26인 설계파라미터와, n$_{eff}$=2.2, Z$_{c}$=47.7.OMEGA.인 설계파라미터를 찾았다.

• Journal of applied mathematics & informatics
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• 제29권1_2호
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• pp.351-367
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• 2011

In this article, we construct exact traveling wave solutions for nonlinear PDEs in mathematical physics via the (1+1)- dimensional combined Korteweg- de Vries and modified Korteweg- de Vries (KdV-mKdV) equation, the (1+1)- dimensional compouned Korteweg- de Vries Burgers (KdVB) equation, the (2+1)- dimensional cubic Klien- Gordon (cKG) equation, the Generalized Zakharov- Kuznetsov- Bonjanmin- Bona Mahony (GZK-BBM) equation and the modified Korteweg- de Vries - Zakharov- Kuznetsov (mKdV-ZK) equation, by using the (($\frac{G'}{G}$) -expansion method combined with the Riccati equation, where G = $G({\xi})$ satisfies the Riccati equation $G'({\xi})=A+BG^2$ and A, B are arbitrary constants.

• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 제15회 정기총회 및 동계학술발표회
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• pp.312-313
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• 2004

The optical gain saturation and noise figure characteristics of 1550nm traveling-wave semiconductor optical amplifiers are analyzed experimentally and theoretically. The result shows that there is an optimum active layer thickness for high saturation output power and low noise figure.

• 한국광학회:학술대회논문집
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• 한국광학회 2008년도 동계학술발표회 논문집
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• pp.291-292
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• 2008

We fabricated 40Gbps electroabsorption modulator-integrated DFB lasers (EMLs). Adopting traveling-wave (TW) electrode and tilted facet improved high-frequency characteristics of EMLs. The 3dB bandwidth of E/O response for TW-EML was as large as 34 GHz, as compared with 27 GHz for lumped EML. Tilted facet formed by dry etching processes successfully reduced the optical feedback and the resonance in E/O response decreased to as small as 2.8 dB.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권6호
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• pp.293-297
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• 2005

Linearity is an important property of optical devices for analog communications. In this paper, we study the 3rd-order interrnodulation distortion (IMD3) of an Inp/InGaAsP multiple-quantum-well (MQW) traveling-wave type electroabsorption modulator (TW-EAM). We observe abnormal notches in the IMD3 results those were different from notches by general transfer curve of electroabsorption modulators (EAMs). We analyze the phenomena through absorption coefficients according to wavelengths and bias voltages to verify appearance of the abnormal notchs, where it can be known to result from Stark-shift and broadening. We propose the method to enhance linearity of MQW-EAMs by using these effects.

• 한국전자파학회논문지
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• 제12권3호
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• pp.451-461
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• 2001

본 논문에서는 주기적인 용량성 부하가 연결된 속도정합 진행파형 전극의 간편한 설계방법을 제시한다. 이 설계 방법에 의하면 속도 정합과 임피던스 정합이 이루어질 수 있는 coplanarstrip(CPS) 전극의 폭과 간격 그리고 용량성 부하의 커패시턴스와 부하간의 간격을 해석적으로 쉽게 결정할 수 있다. GaAs를 기판으로 하는 속도정합 진행파형 전극의 계산결과 100 GHz 이상의 대역폭을 갖는다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1033-1035
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• 2003

Linear induction motor with multilayer region of the single-sided is analyzed considering multi region traveling wave problem. A hybrid method of analysis consisting of field analysis in conjunction with the multilayer transfer matrix concept with adjustment of secondary iron permeability to match the tangential magnetizing field in each layer is developed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.96-97
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• 2007

A stator of ultrasonic motor of high torque with a new configuration is proposed. The stator designed newly is two sided vibrator consisting of toothed metal disk with piezoelectric ceramic ring bonded on both face of disk. which generates a flexural traveling wave along the circumference of disk. it produces a large vibrating force and amplitude because the vibrator is sandwiched by two piezoelectric ring. The finite element method was used to compute the vibration mode of the stator with a outer diameter of 48mm. A 6th vibration mode was chosen as operation mode with resonance frequency about 72kHz. According to the design, the prototype stator was fabricated and its performance was measured.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.63-64
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• 2006

Recently, researches for high-speed optical devices have been increased to provide mass data transmission and high-speed optical communication. Optical modulator in the transmission link is one of the crucial devices in total optical network system and it can affect a great effect to the whole transmission properties. In this paper, traveling wave electro-absorption modulator (TWEAM) is examined to ensure high efficiency in the RF range and wide bandwidth. In addition, the temperature-dependence electrical characteristics of TWEAM is investigated. Temperature dependent property variations were characterized using I-V and C-V measurement.