• 한국전기전자재료학회논문지
• /
• 제18권11호
• /
• pp.1048-1055
• /
• 2005

The formula to calculate a variation of optical path length of single crystal by the electric field was derived by this study. The formula was applied to $Bi_{12}SiO_{20}$ single crystal. The results are as follows. In case of the applied electric field in the body diagonal direction and the passing light along the same direction, the variation of optical path length had the largest value. The symmetry of the space distribution of optical path length satisfied $E3C_2\;8C_3$, the set of elements of the symmetry of $Bi_{12}SiO_{20}$ single crystal. The property which gave the largest influence to the variation of optical path length is the strain of length by the Inverse piezoelectric effect. The second influence, is the variation of the refractive index by the electro-optic effect. The variation of optical path length by the inverse piezoelectric effect and by the electro-optic effect have a reverse sign each other.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2005년도 제16회 정기총회 및 동계학술발표회
• /
• pp.184-185
• /
• 2005

• Journal of the Optical Society of Korea
• /
• 제17권4호
• /
• pp.296-299
• /
• 2013

A low density lipoprotein (LDL) cholesterol testing device, structured with serial reflected face-to-face mirror (SRM) allowing spectrophotometry measurements, is presented. The spectrophotometry has been employed to measure the amount of light that a sample absorbs, but it generally should have had path length longer than 10 mm to secure enough sensitivity. Such requirement of path length has often been problematic in implementing a thin type of lab on a disc (LOD). We developed the SRM system which was implemented in a detection chamber with 1.4mm thickness, providing path length longer than 10mm, and thus straightforwardly being applicable to LOD as thin as a compact disc. The experimental results show that the SRM system gives not only a much thinner design compared to the conventional spectrophotometry-based LOD but also a comparable performance to already commercialized spectrometers.

• 한국정보통신학회논문지
• /
• 제11권5호
• /
• pp.985-990
• /
• 2007

코히런트 광섬유 센서의 해상도를 향상시키기 위하여 광원의 코히런스 길이를 향상시키는 방법에 대하여 연구하였다. 넓은 파장범위에 걸쳐서 레이저 광을 생성할 수 있고 발광 파장대역이 장거리 전송이 가능한 통신용 광섬유의 저 손실 대역인 광섬유 레이저의 코히런스 길이를 향상시키기 위하여 레이저의 광궤환 기법을 이용하였다. 본 논문에서는 광섬유 레이저의 단거리 및 장거리 광궤환 루프가 코히런스 길이에 미치는 영향을 Mach-Zehnder Interferometer를 이용하여 연구하였다. 광궤환 전력량과 광궤환 루프에서의 변조형태가 코히런스에 미치는 영향을 조사하였다. 주파수 천이도는 200m 길이차를 갖는 비대칭 간섭계에서의 위상간섭 정도를 측정하여 계산하였다. 광섬유 레이저에서 단거리 광궤환 루프는 450kHz/sec로 주파수 천이도를 축소시키는데 효과가 있었고 장거리 광궤환 루프는 50kHz/sec로 주파수 천이도를 더 향상시키는 효과가 있음을 알 수 있었다. 실제 코히런트 광센서에 응용 시 고감도 침입자 감지가 기대된다.

• Journal of the Optical Society of Korea
• /
• 제15권4호
• /
• pp.380-385
• /
• 2011

Common-path interferometers are widely used for endoscopic optical coherence tomography (OCT) because an arbitrary arm length can be chosen for the endoscopic imaging probe. However, the scheme suffers from the limited range of the sample position distance from the end of the imaging probe because the position between the reference reflector and the sample is limited by the optical path-length difference (OPD) to induce an interference signal. In this study, we developed a novel method for compensating the arbitrary sample position in common-path swept-source OCT by adding an extra Mach-Zehnder interferometer in the post-path of the interfered optical signal. Theoretical analysis and an experimental demonstration of imaging depth tuning for the flexible sample position of an endoscopic OCT image are discussed. After post-tuning of sample position distance, the positioning limitation between the reference reflector and the sample can be solved for various sample positions over a range of 26 mm for the cross-sectional images of a fish eye sample.

• The Journal of the Acoustical Society of Korea
• /
• 제21권1E호
• /
• pp.25-30
• /
• 2002

We report on the development of a fiber optic hydrophone consists of a sensing Michelson interferometer and a compensating Mach-Zehnder interferometer for optical path length compensation. The double interferometer configuration has the following advantages: the hydrophone can be made more small; a laser source with a relatively short coherence length can be used; and the compensating interferometer can be located near the signal processing electronics, far away from the sensing interferometer and noise introduced by reference arm can be greatly reduced. The performance of the hydrophone is evaluated experimentally by immersing the sensing interferometer in a water tank to detect underwater acoustic signals generated by an acoustic wave projector. Experimental results show that over the frequency range of 1 to 4 kHz, the hydrophone has an almost flat response with an average normalized sensitivity of -302 dB re 1/ μ Pa.

• 대한전자공학회논문지TC
• /
• 제40권10호
• /
• pp.35-42
• /
• 2003

본 논문에서는 광 버스트 교환 방식에서 사용되는 제어 패킷 처리 시간 보상 기법 및 자원 예약 기법을 분류하고 다중 홉 환경에서 대표적인 예약 방식인 OT/DR (Offset Time/Delayed Reservation) 기반 JET(Just-Enough-Time) 방식의 문제점인 Path length priority effect를 분석하였다. 그리고, 이러한 문제점을 해결하면서 입력 FDL(Fiber Delay Line)을 사용하여 홉 단위로 우선 순위를 증가시켜 종단간 수율을 개선시킬 수 있는 FDL/DR 방식 기반의 홉 단위 우선 순위 증가 기법을 제안하고 시뮬레이션을 통하여 성능을 비교 분석하였다. 시뮬레이션을 통한 성능 분석 결과 제안된 방식은 다중 홉 환경에서 path length priority effect로 인해 발생하는 기존 방식의 문제점을 개선하여 종단간 성능이 향상됨을 알 수 있었다.

• International Journal of Internet, Broadcasting and Communication
• /
• 제14권3호
• /
• pp.63-68
• /
• 2022

Two wavelength reconfigurable optical nodes are designed. One for 20km or shorter link length, and the other for up to 60km link length. While the first one requires no dispersion compensation, the latter needs dispersion compensation fiber included in the node, which requires additional optical amplifier to compensate the insertion loss of DCF. We calculate all the optical path losses in both cases using the typical value of optical components in the market to see the feasibility of the designed optical node. The minimum received power in the node is calculated to be -21.5dBm without DCF and -12.5dBm with DCF, respectively. These received powers are above the receiver sensitivity both for OC-48 and OC-192 according to the previous work.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2008년도 하계학술발표회 논문집
• /
• pp.273-274
• /
• 2008

We present a quantitative phase microscopy for live cells. This method uses the principles of common path inteferometry and single shot phase image. This system has the ability to measure live cells quantitatively with subnanometer path length stability and millisecond scale aquisition time.

• 한국광학회:학술대회논문집
• /
• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
• /
• pp.113-118
• /
• 1989

By using the single mode optical fiber, we fabricated Fiber-optic Fabry-Perot interferometer (FFPI). The change over a wide range in the optical path length of a FFPI is observed. The temporal movement of the interference fringes by external condition to P.Z. T) is converted to circular motion on an oscilloscope display and then recorded with a micro-computer. The two output voltages of the D/A converters are applied to X and Y terminals of oscilloscope to display circular motion on oscilloscope. Thus the direction of phase shift can be determined with observing the direction of circular motion. The variation of the optical length can be measured by calculating the angle of spot of circle with an accuracy of λ/90 wave length due to variation of temperature in this system 2.7x10-4$^{\circ}C$.