• ETRI Journal
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• 제29권6호
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• pp.808-810
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• 2007

We demonstrate 10 Gbps optical signal transmission via long-range surface plasmon polaritons (LR-SPPs) in a very thin metal strip-guided geometry. The LR-SPP waveguide was fabricated as a 14 nm thick, 2.5 ${\mu}m$ wide, and 4 cm long gold strip embedded in a polymer and pigtailed with single-mode fibers. The total insertion loss of 16 dB was achieved at a wavelength of 1.55 ${\mu}m$ as a carrier wave. In a 10 Gbps optical signal transmission experiment, the LR-SPP waveguide exhibits an excellent eye opening and a 2.2 dB power penalty at $10^{-12}$ bit error rate. We confirm, for the first time, that LR-SPPs can efficiently transfer data signals as well as the carrier light.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.1119-1122
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• 1990

Presnted is a new optical transmission system to transmit the FM control signal (80 MHz) through an optical fiber by the use of an inexpensive LED having a cutoff frequency of as low as 30 MHz. Studies are carried out on the division of the FM signal frequency at 80 MHz by a factor of four. The FM signal frequency is, after the transmission through the optical fiber, then multiplied by a factor of four so as to obtain the normal FM control signal.

• 센서학회지
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• 제23권1호
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• pp.1-6
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• 2014

In many medical image devices, dc noise often prevents normal diagnosis. In wireless capsule endoscopy systems, multipath fading through indoor wireless links induces inter-symbol interference (ISI) and indoor electric devices generate impulsive noise in the received signal. Moreover, dc noise, ISI, and impulsive noise are also found in optical fiber communication that can be used in remote medical diagnosis. In this paper, a blind signal processing method based on the biased probability density functions of constant modulus error that is robust to those problems that can cause error propagation in decision feedback (DF) methods is presented. Based on this property of robustness to error propagation, a DF version of the method is proposed. In the simulation for the impulse response of optical fiber channels having slowly varying dc noise and impulsive noise, the proposed DF method yields a performance enhancement of approximately 10 dB in mean squared error over its linear counterpart.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권1호
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• pp.15-19
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• 2004

In this paper, we present the fabrication and characteristic analysis of Sagnac interferometric optical fiber senior(OFS) system for detecting pulsed ultrasonic signal in underwater. The hollow cylindrical mandrel wound round by single mode optical fiber is used as sensing component. The ultrasonic signal source is simulated by the PZT actuator operated by an function generator. The distance dependency of the OFS's sensitivity was measured. The sensitivity has been shown to be inversely propotional to the square-root of distance between ultrasonic source and sensing component. It has also been shown that the OFS could detect the signals less affected by ultrasonic path comparing to conventional acousto-electric sensor. and accurate location of ultrasonic signal could be carried out using two OFSs.

• Journal of the Optical Society of Korea
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• 제1권1호
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• pp.1-4
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• 1997

The theoretical limit of the noise correlation between the signal and idler outputs of a nondegenerate optical parametric amplifier (NOPA) with a coherent state signal and vacuum state idler input can be enhanced if a non-vacuum coherent state idler input is employed. By choosing a balanced signal and idler input, the noise correlation is $1/{({\root}g + {\root}{g-1})}^2$, where g is the intensity gain of the NOPA, and that is superior to the prediced outputs with single signal input by approximately 3dB. The result is applicable to all the schemes that use the NOPA to produce a sub-shot noise light generation such as feed-back or feed-forward control.

• 한국전자파학회논문지
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• 제11권5호
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• pp.822-829
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• 2000

본 논문에서는 무선광열에서 잡음광의 영향을 소거하는 동시에, 신호광원의 미세한 정렬변동에 의하여 빔의 진행방향이 이동할 경우 발생하는 출력전압의 변동을 막기 위한 자동정렬형 차동검출기를 개발하여 소개한다. 이 구조에서는 신호빔과 수직한 포토다이오드 배열을 사용하여 빔의 중심위치를 감지하고, x축과 y축에 해당하는 모토를 구동한다. 포토다이오드배열은 자신의 위치가 항상 신호빔의 중심에 오도록 자동적으로 조절하는 동시에 차동검출방식으로 잡음광의 영향을 소거하는 기능을 가지므로 무선광연결에서 매우 유용하게 쓸수 있다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 추계학술대회
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• pp.139-140
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• 2010

This paper presents an indoor prototype for wireless digital signal transmission using Visible Light Communications (VLC) in which high power Light Emitting Diode (LED) is used. Using low cost and off-the-shelf components, the transmitter module is constructed using an AVR Atmega128 microcontroller and commercial white beam LEDs. Modulating the light intensity of the LED enables digital signals to be transmitted across the optical link. The receiver module employs a high speed PIN photodetector for optical signal detection and a recovery circuit for optical-electro signal conversion. By sending digitalized data via VLC technology, many applications can be realized in the areas of consumer advertising, traffic safety information and disaster control.

• Journal of the Optical Society of Korea
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• 제17권6호
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• pp.491-493
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• 2013

This paper proposes a frequency-doubling optoelectronic oscillator employing a novel three-arm dual-output Mach-Zehnder modulator (MZM). One output of the MZM generates the fundamental-frequency signal which is recycled by the microwave optical fiber link for oscillation, and the other output can generate the frequency-doubled signal. Experiment was conducted using a commercial two-arm MZM, a phase modulator, and an optical fiber link of 89 meters in length. A 19-GHz frequency-doubled signal was successively obtained with fundamental signal suppression more than 36 dB.

• 센서학회지
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• 제30권4호
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• pp.196-203
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• 2021

In this study, an optical identification system was developed, wherein visible light is used to transmit the interrogating signal, and infrared is used to send the response signal. In the reader, visible light from a light emitting diode (LED) array was modulated via modified pulse width modulation for flicker-free illumination and dimming control. Moreover, the duty factor of the dimming control time was employed to control the illumination from the LED. In the transponder, the spike signal in the output of the high-pass filter was utilized to recover the interrogating signal while preventing interference from the 120-Hz noise from adjacent lighting lamps. The illumination was controlled in 26-86% range of the constant wave LED illumination by changing the duty factor from 20% to 90%. This configuration is advantageous for the construction of optical identification systems for automatic security check and car fare calculation at toll gates or parking facilities.

• 한국광학회:학술대회논문집
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• 한국광학회 1996년도 Advance Program of 13th optics andquantum Electronics conference, 1996제13 회 광학 및 양자전자 학술 발표회 논문 요약집
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• pp.36-36
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• 1996