• 한국고분자학회지:고분자과학과기술
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• 제21권1호
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• pp.3-9
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• 2010

• Journal of the Optical Society of Korea
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• 제15권1호
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• pp.9-14
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• 2011

In this study, the internal structure of an optical waveguide embedded in a flexible optical circuit board is observed with a confocal microscope. In order to increase the light reflection from an internal material interface with a very small index difference, and thus enhance the signal contrast, a theta microscopy scheme has been integrated into a conventional confocal microscope, and a high NA oil-immersion lens has been used. The interface reflectivity is increased from roughly 0.0015% to 0.025% by the proposed method, and the internal structure can thus be successfully measured.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.275-277
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• 1999

A application possibility of photoresist flexible film for optical waveguide is proposed and described. The optical waveguide dimensions that is consists of Mach-zehnder interferometric and single channel waveguide based on the single-mode conditions in LiNbO$_3$ device was utilized and fabricated by wet etching technique. This Polymer material for core layer is SU-8/5O(Microchem.) and its refractive index from prism couping method was measured about 1.59 thickness about 10${\mu}{\textrm}{m}$ at wavelength 0.6328${\mu}{\textrm}{m}$. From the results, this work can show the possibility of fabricating a flexible optical waveguide in the field of integrated optics.

• 한국광학회지
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• 제23권1호
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• pp.12-16
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• 2012

본 논문에서는 연성 광 인쇄회로기판(printed circuit board, PCB) 개발을 위한 핵심 부품인 연성 광도파로를 자외선 임프린트(ultra violet imprint, UV-imprint) 공정에 의해 제작하고 도파손실, 굴곡손실, 반사손실 및 반복굴곡에 대한 내구성을 측정하였다. 먼저, 초정밀 기계가공에 의해 광도파로 패턴과 $45^{\circ}$ 미러 구조를 포함하는 니켈 마스터를 제작 후 폴리디메틸실록산(polydimethylsiloxane, PDMS)를 이용하여 탄성체 몰드를 역상 복제 하였다. 역상 복제된 PDMS 몰드를 이용해 UV-imprint 공정에 의한 광도파로의 코어패턴과 $45^{\circ}$ 미러면을 동시 형성하여, $45^{\circ}$ 미러가 내장된 광도파로를 제작하였다. 또한, 광도파로의 끝단을 통상적 방법인 V-sawing 공정으로 $45^{\circ}$ 미러 구조를 가공하여 미러 내장형 광도파로와 미러 특성을 비교하였다. 제작된 연성 광도파로는 단위 길이당 0.035 dB/cm의 도파손실을 나타내었으며, 반경 1 mm의 $180^{\circ}$ 굴곡 조건에서 0.77 dB의 굴곡손실을 나타내었다. 또한, 굴곡각도 $135^{\circ}$, 굴곡반경 2.5 mm의 반복굴곡 실험에서 10 만회 이상의 반복굴곡에 대한 우수한 내구성을 확인하였다. 내장된 $45^{\circ}$ 미러의 반사효율을 향상시키기 위해 미러면에 Ni-Au 이중 박막을 증착하여 2.18 dB의 반사손실을 가진 미러내장형 연성 광도파로를 제작하였다.

• Current Optics and Photonics
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• 제6권4호
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• pp.375-380
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• 2022

We demonstrate two types of light field displays based on waveguide grating coupler arrays: a line beam type and a point source type. Ultra violet imprinting of an array of diffractive nanograting cells on the top surface of a 50-㎛-thin slab waveguide can deliver a line beam or a point beam to a multidirectional light field out of the waveguide slab. By controlling the grating vectors of the nanograting cells, the waveguide modes are externally coupled to specific viewing angles to create a multidirectional light field display. Nanograting cells with periods of 300 nm-518 nm and slanted angles of -8.5°~+8.5° are fabricated by two-beam interference lithography on a 40 mm × 40 mm slab waveguide for seven different viewpoints. It is expected that it will be possible to realize a very thin and flexible panel that shows multidirectional light field images through the waveguide-type diffraction display.

• 한국광학회지
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• 제18권2호
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• pp.149-154
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• 2007

저가의 소자 개발이 가능한 나노임프린팅 공정을 도입하여 510 nm 주기의 브래그 격자 구조를 가지는 폴리머 광도파로 소자를 제작하였다. 폴리머 격자 광소자의 온도 의존성을 감소시키기 위한 방법으로 플라스틱 박막으로 이루어진 유연성 기판상에 브래그 격자를 제작하는 것이 필요하다. 임프린팅 공정을 손쉽게 수행하기 위한 광도파로 구조를 채택하였으며, 코아와 클래딩의 굴절률이 각각 1.540, 1.430인 폴리머를 이용하여 코아 두께가 $3{\mu}m$인 단일모드 광도파로 구조를 얻을 수 있었다. 유연성 기판 브래그 격자 광도파로 소자의 특성을 Si기판 브래그 격자 광도파로 소자와 비교하여 관측한 결과, 유연성 기판 도입에 따른 브래그 반사 소자의 성능 저하는 나타나지 않았다.

• Journal of the Optical Society of Korea
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• 제17권2호
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• pp.172-176
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• 2013

For demonstrating widely tunable external cavity lasers operating for near-infrared (NIR) wavelength, a flexible polymer waveguide with an imbedded Bragg grating is incorporated. Due to the superior flexibility of the polymer material, the reflection wavelength of the Bragg grating is widely tunable by imposing tensile and compressive strains on the flexible Bragg grating. A third-order Bragg grating is formed on the device for facilitating the fabrication method. With a superluminescent laser diode as a gain medium of ECL, the tunable laser exhibited output power of -3 dBm and a tuning range of 32 nm.

• 로봇학회논문지
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• 제8권3호
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• pp.156-163
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• 2013

This paper describes a flexible visuo-haptic display module. We have developed a flexible electro-active polymer (EAP) actuator and a thin flexible visual display with $3{\times}3$ array configuration via polymer technology. The flexible actuator consists of nine EAP cells vertically moving in response to change in their thickness. The flexible display uses polymer based optical waveguide allowing light to scatter only at specific area. The display film is transparent and identically designed to the array pattern to fit for the arrangement of actuator cells. A pressure sensor is installed under the integrated module. The performance of the actuator is proved to be sufficient for satisfying perceivable range of human touch sense. The integrated system can provide interactive haptic feedback such as key pressing, contact vibration sensations, and etc. in accordance with user input.

• ETRI Journal
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• 제18권2호
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• pp.75-86
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• 1996

A new method is proposed for the analysis of optical properties of stationary transverse electirc (TE) nonlinear waves in the five-layer waveguide which consists of a linear guiding layer with two nonlinear bounding layers sandwiched between a semi-infinite clad and a substrate. By using the relation of the interface electric fields, we obtain the generalized form of nonlinear dispersion equations as an analytic and flexible form. In order to verify the dispersion equation, we apply the dispersion equation to the analysis of the symmetric five-layer waveguide. The nonlinear dispersion curves for several thicknesses of the nonlinear thin film is also presented.

• 한국정밀공학회지
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• 제21권5호
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• pp.38-45
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• 2004

As optical communication is being substituted for telecommunication, the demand of a large variety of fiber optic components is increasing. V-groove substrates, one of the module components, are used to connect optical fibers to optical planar circuits and to arrange fibers. Their applications are multi-channel optical connectors and optical waveguide fiber coupling, etc. Because these substrates are a critical part of the splitter in a multiplexer and a multi fiber connector, precise and reliable fabrication process is required. For precisely aligning core pitch between fibers, machined core pitch tolerance should be within sub-microns. Therefore, these are generally produced by state-of-the-art micro-fabrication like MEMS. However, most of the process equipment is very expensive. It is also difficult to change the process line for custom designs to meet specific requirements using various materials. For various design specifications such as different values of the V angle and low-priced process, the fabrication method should be flexible and low cost. To achieve this goal, we have suggested a miniaturized machine tool with high accuracy positioning system. Through this study, it is shown that this cutting process can be applied to produce V-groove subtracts. We also show the possibility of using a miniaturized machining system for producing small parts.