• Electronics and Telecommunications Trends
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• v.8 no.3
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• pp.207-221
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• 1993

광 커플러는 광섬유로부터 광신호를 분기하거나 결합하는 광통신망의 가장 기초적인 부품으로 광통신망에서 다양한 기능을 수행하고 있다[1]. 따라서 광 커플러는 광통신망의 구성에 있어서 가장 중요한 부품의 하나이며, 특히 광가입자망의 구현에 따라 그 수요가 크게 증가될 전망이다. 현재 가장 일반적인 광 커플러는 Evanescent 광 결합원리를 이용하는 광섬유형 근접 커플러이며, 그 이외에도 각종 평면도파로를 이용한 도파로형 커플러가 제품의 소형화 및 양산성이 우수하여 많은 연구개발이 진행되고 있다. 본고에서는 현재까지의 각종 광 커플러의 기술 및 시장 현황을 통신용 단일모드 광 커플러를 중심으로 고찰하고 앞으로의 광 커플러 개발 방향을 제시하고자 한다.

• Korean Journal of Optics and Photonics
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• v.15 no.6
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• pp.485-489
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• 2004

We demonstrated numerically that both the chromatic dispersion and the dispersion slope could be compensated by using purely phase-sampled superstructure fiber Bragg gratings provided with chirp of coupling coefficient along the wavelength axis. Also, we propose a purely phase-sampled Bragg grating for dispersion and dispersion slope compensation by introducing a chirp in coupling coefficient and sampling function. The bandwidth of all reflected channels can be equalized.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.9
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• pp.7-14
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• 2000

This paper examines the constraints imposed in the usage of the conventional two-mode coupling model in the context of a cascaded long-period fiber grating and presents a set of approximate conditions that must be satisfied for the model to be applicable in the analysis of such a structure. Numerical examples based on the guidelines are provided for a set of realistic grating parameters and their practical implications on the allowed grating period variations for a given bandwidth are discussed.

• Korean Journal of Optics and Photonics
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• v.16 no.2
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• pp.138-142
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• 2005

In this paper, a method to eliminate the polarization dependent properties of fiber-to-planar waveguide couplers using a thin half-waveplate is proposed and demonstrated. The operation principle of the device is explained and the fabrication technology is presented. It is experimentally shown that the resonance wavelengths of the device are independent of the polarization state of input light.

• Korean Journal of Optics and Photonics
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• v.10 no.3
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• pp.248-253
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• 1999

In this paper, we have investigated a fiber type active coupler which utilizes the mode coupling between the side polished single mode optical fiber and the active multimode planar waveguide. The proposed device can be used for not only tunable wavelength filter or optical intensity modulator but also a tool for measuring optical properties of guiding material such as refractive index, birefringence, electro-optic coefficient, and thermo-optic coefficient. We gave designed and optimized a coupler structure using the BPM and fabricated the device using thermo-optic polymer as active planar waveguide overlay. The device showed that insertion loss was less then 0.5 dB, extinction ratio was -13 dB at the resonance wavelength, and the wavelength tunablity due to thermo-optic effect was -1.5 nm/$^{\circ}C$. The active coupler using thermo-optic effect can be used as a wavelength tunable filer, an optical intensity modulator and an optical sensor. pulses that are subsequently compressed by a dispersive optical fiber. Experimental results show that $sech^2$ shape pulses with a pulse width of ~14 ps and a time bandwidth product of ~0.34 are successfully generated at 10 GHz repetition rate. In contrast to other methods, such as higher order soliton compression, this approach does not depend on the optical power and thus shows promise for application to low-power lasers.

• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.265-266
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• 2006

• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.257-258
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• 2006

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.421-422
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• 2006

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.42-43
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• 2002

• Journal of Sensor Science and Technology
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• v.9 no.1
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• pp.15-21
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• 2000

Optical fiber temperature sensor, using resonance wavelength shifting of single mode fiber-to-planar waveguide coupler by heat, was fabricated. Thermo-optic polymers, have large change of refractive index due to heat, were used for planar waveguide. The device fabrication procedure including fiber polishing steps was illustrated and the device structure with independent polarization was demonstrated experimentally. The resonance wavelength difference of fabricated device was less than 2nm. The resonance wavelength shifting owing to temperature variation, from room temperature($24^{\circ}C$) to $90^{\circ}C$, was showed $-0.54nm/^{\circ}C$, $-3nm/^{\circ}C$.