• Journal of the Optical Society of Korea
• /
• 제13권2호
• /
• pp.261-266
• /
• 2009

The angular dispersion-type non-scanning Fabry-Perot was applied to an ethanol-water mixture in order to investigate its acoustic properties such as the sound velocity and the absorption coefficient. The scattered light from the mixture was analyzed by using the charge-coupled-device area detector, which made the measurement time much shorter than that obtained by using the conventional scanning tandem multi-pass Fabry-Perot interferometer. The sound velocity showed a deviation from ultrasonic sound velocities at low temperatures accompanied by the increase in the absorption coefficient, indicating acoustic dispersion due to the coupling between the acoustic waves and some relaxation process. Based on a simplified viscoelastic theory, the temperature dependence of the relaxation time was obtained. The addition of water molecules to ethanol reduced the relaxation time, consistent with dielectric measurements. The present study showed that the angular dispersion-type Fabry-Perot interferometer combined with an area detector could be a very powerful tool in the real-time monitoring of the acoustic properties of condensed matter.

• 한국정밀공학회지
• /
• 제21권5호
• /
• pp.142-148
• /
• 2004

In this paper, to detect exciting frequency on the latticed fence structure, fiber optic sensor using Sagnac interferometer was fabricated and tested. The latticed structure fabricated with dimension of 180 cm wide and 180 cm high, the optical fiber, 50 m in length, distributed and fixed on the latticed structure. Single mode fiber, a laser with 1,550 m wavelength, and $3{\times}3$ coupler were used. Excited vibration signal applied to the latticed structure from 200 Hz to 1 KHz. The detected optical signals were compared to the detected acceleration signals and analyzed on the time and frequency domain. Based on the experimental results, fiber optic sensor using Sagnac interferometer detected exciting frequency, effectively. This system can be applied to the structural health monitoring system.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2007년도 동계학술발표회 논문집
• /
• pp.19-20
• /
• 2007

• 한국광학회:학술대회논문집
• /
• 한국광학회 2002년도 제13회 정기총회 및 2002년도 동계학술발표회
• /
• pp.208-209
• /
• 2002

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2006년도 하계종합학술대회
• /
• pp.105-106
• /
• 2006

It is important to identify the exact target optical cable that a worker look for when he executes a cable construction work. Until now, An Optical cable identification work has been done by a manual pulling of an optical cable or by the method of using RF signals. But these methods not only consume much time and labor costs but also have a distance limit of the optical cable to identify. In this paper, we propose a method that uses the phase change signal of the optical interferometer to identify an optical cable. With the proposed method the field worker can have an efficient tool to prevent miscutting the optical cable and can also save operating costs.

• 한국인터넷방송통신학회논문지
• /
• 제11권4호
• /
• pp.141-145
• /
• 2011

마크-젠더 변조기와 광 필터를 사용하여 광 듀오바이너리 신호를 생성하는 광 듀오바이너리 송신기의 분산 내성을 이론적으로 분석하였다. 송신기의 전송 성능은 마크-젠더 변조기와 광 간섭계를 사용하고 구동 전압 조정으로 최적화하여 분산 내성을 향상 시킨 광 듀오바이너리 송신기와 비교하였다. 그 결과 광 필터를 사용한 광 듀오바이너리 송신기는 좁은 스펙트럼 대역폭을 유지하면서 광 간섭계를 사용한 광 듀오바이너리 송신기보다 개선된 수신 감도와 더 높은 분산 내성을 나타냈다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
• /
• pp.310-312
• /
• 2009

The heterodyne laser interferometer has been widely used in precise measurement field. However, the accuracy is limited by the nonlinearity error caused from incomplete laser sources and nonideal optical components. In this paper, we propose the Dual-EKF which estimates states and weights simultaneously to improve the resolution of heterodyne laser interferometer. As a proof, we demonstrate the effectiveness of our proposed method through experimental results.

• 조명전기설비학회논문지
• /
• 제18권2호
• /
• pp.29-35
• /
• 2004

Two-pupil 합성방법을 이용하여 변형 삼각간섭계의 광전달함수를 합성하고 분석하였다. 그리고, 변형 삼각간섭계의 경우에 two-pupil 방법을 사용함으로써 바이폴라 함수를 구하여 바이어스가 제거된 복소홀로그램을 얻을 수 있다는 것을 입증하였다.

• ETRI Journal
• /
• 제26권4호
• /
• pp.344-350
• /
• 2004

We propose a filter-free wavelength conversion using a Mach-Zehnder interferometer with monolithically integrated $2{\times}2$ multimode interference semiconductor optical amplifiers (MMI-SOAs). The device has been optimized by considering a non-homogeneous carrier distribution due to the self-imaging properties of the MMI-SOA. Static measurements show an extinction ratio of up to 18 dB and an input signal rejection ratio of up to 20 dB.

• Journal of the Optical Society of Korea
• /
• 제14권4호
• /
• pp.363-367
• /
• 2010

A new two step on-axis digital holography (DH) is proposed without any assumptions, phase shifting, or complicated optical components. A dual-channel Mach-Zehnder interferometer was employed. Using that setup, the object field can be reconstructed requiring only two step measurements. To eliminate position difference between two charge-coupled device (CCD) cameras, a matched filter algorithm was used. Experimental results are compared to those of the traditional phase shifting technique. The proposed approach can also be applied to single-exposure on-axis DH for real time measurement.