• Journal of the Optical Society of Korea
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• 제1권1호
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• pp.44-47
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• 1997

The integration of a GaAs/AlGaAs multi-quantum well electroabsorption modulator and a tapered waveguide vertical direction optical interconnect has been performed without the complicated regrowth process. Zn impurity-induced layer disordering of MQW layer is used to achieve the energy transfer between SQW and MQW regions. Light coupled into a SQW region was transferred to an MQW region and an intensity modulation of 10 dB extinction ratio was demonstrated.

• Journal of the Optical Society of Korea
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• 제18권3호
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• pp.288-291
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• 2014

This paper presents a new method for measuring the half-wave voltage $V_{\pi}$ of an electro-optic phase modulator based on a phase-modulated photonic link with interferometric demodulation. By using this method, the $V_{\pi}$ can be obtained with the RF voltage amplitude input required to achieve 1-dB gain compression of link and the differential delay of a Mach-Zehnder interferometer. We measure the $V_{\pi}$ of a commercial phase modulator by using the presented method and the carrier/the first sideband intensity ratio method. Furthermore, we compare the two measurements with the typical value provided by the manufacturer. The experiment shows that this novel measurement method is feasible, straightforward, and accurate.

• 조명전기설비학회논문지
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• 제22권11호
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• pp.9-14
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• 2008

This paper presents the performance analysis of 10[Gb/s] optical duobinary transmitters with the non-ideal Mach-Zehnder modulator which does not have exactly 50/50 splitting/combining ratios by computer simulations. For driving voltage ratios(=driving voltage/switching voltage) with smaller than 100[%], the transmission performance has been greatly affected by extension of LPF bandwidths. Nevertheless, the performance has been degraded when the driving voltage ratio is 100[%]. The smaller driving voltage ratios has, the more sensitivity improves by extension of LPF bandwidths under the asymmetry condition. But the driving voltage ratio with 80[%] has better bit error rate(BER) than those with 50[%] and 25[%].

• 전자공학회논문지D
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• 제34D권8호
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• pp.80-86
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• 1997

H:LiNbO$_{3}$ optical modulator buffered by parylene layer, which has a merits in the bandwidth, power consumption and fabrication as compared with conventional SiO$_{2}$ buffered optical modulator, is proposed and analyzed. The dependences of velocity matching condition, charcteristics impedance, and driving voltage on dielectric constants, thickness of buffer layer, and electrode configurations are demonstrated with finite element calculation. And we performed the physical and chemical test of parylene buffer layer deposited on LiNbO$_{3}$ and under Au electrodes.

• 대한전자공학회논문지TE
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• 제37권3호
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• pp.1-5
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• 2000

A waveguide of coupled optical modulator was fabricated on LiNbO$_3$ based on proton exchange with self-aligned thin film electrode method. The electrode pattern was designed using a self-aligned method. After proton exchange process, the waveguide was prepared by annealing process. The initial crossover state of the fabricated 2$\times$2 coupled optical modulator was observed with controlling the annealing process variables and the structure of self-aligned thin film electrodes. It was shown form the present work that the measured crosstalk is -29.5[dB] and 8.0[V] of detected modulating voltage.

• 센서학회지
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• 제8권4호
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• pp.333-340
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• 1999

전자계계측 센서를 구성하기에 편리한 반사간섭형 광변조기를 제안하고, 그 동작원리와 기본특성을 이론적으로 해석하였다. 센서의 고감도화를 위하여 반사간섭형광변조기의 변조도 개선방법을 제시하였으며, $LiNbO_3$ 기판으로 반사간섭형 광변조기를 제작하여 센서를 구성하고, 저주파 전자계 측정실험을 실시하여 센서의 정성적 특성을 평가하였다. 실험에서 5% 정도의 낮은 변조도에서도 5 V/cm 의 계측결과를 얻어 전계계측센서로서 활용 가능성을 확인하였다.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 하계학술발표회
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• pp.34-35
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• 2000

A Y-branch phase modulator made of an electro-optic(EO) polymer has been designed and fabricated. An EO polymer, PMMA-DR1, is used for the core layer, and UV-curable polymers, UV-15 and UV-15 LV, for the cladding layers. The rib type polymeric waveguides are fabricated by the reactive ion etching method and their EO effects are obtained by the poling process. The optical properties of the fabricated phase modulator are as follows: the halfwave voltage, $V_{\pi}$, is 25 V, the insertion loss of TM mode is 13.8 dB, and the intensity modulation is 0.17 % (V).

• 한국광학회지
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• 제13권5호
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• pp.408-413
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• 2002

We demonstrated a polarization dependent type 2$\times$2 optical switch, using a binary reflection type SLM. Reflection type FLC was used as a half wave retardation plate. Two inputs were controlled by each SLM for the desired output direction. In conclusion, in the "1" state the average optical loss was 6.6 ㏈, and in the "0" state the average optical loss was 14.6 ㏈, and measured the switching speed as 75 $mutextrm{s}$. By using this method, a polarization dependent type 2$\times$2 optical switch can be demonstrated and the possibility of a 4-port WDM optical switch also verified.

• 전자공학회논문지D
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• 제35D권11호
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• pp.91-99
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• 1998

본 논문에서는 광통신용 5Gbps급 LiNbO₃ 패키징(packaging)하여 그 제반특성을 조사하였다. 광위상변조기의 광도파로는 양자교환법(APE, annealed proton exchange)으로 제작하였고 마이크로파전극은 ACPS(asymmetric coplanar strip)로 설계하였다. 소자특성으로 제작한 LiNbO₃위상변조기를 파장 1550nm에서 구동시켰을 때 소자의 변조대역폭, 삽입손실 및 구동전압은 각각 7㎓, 3.0dB 및 6V를 나타내었다.

• 전자공학회논문지D
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• 제36D권6호
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• pp.87-96
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• 1999

협대역 마이크로파 아날로그 광전송을 위한, 이중 변조구조를 이용한 새로운 전광 전계흡수 광변조기의 선형화 방법이 제안되었으며, 이론적으로 고찰되었다. 주-변조기와 소자 길이, 흡수층의 밴드갭 파장 그리고 DC 바이어스 전압을 달리하는 부-변조기의 주-변조기와의 이중 변조구조를 적용하여, 주-변조기의 3차 비선형 왜곡 성분인 CTB(composite triple beat distortion)를 최소화하는 동작점이 작은 바이어스전압으로 이동함과 더불어 ~30dB의 CYB의 억제효과를 얻을 수 있었다. CTB의 억제에 따라 협대역 채널 대역에서의 ~20dB 동작영역의 향상을 이룰 수 있었다.