광섬유 Mach-Zehnder 간섭계를 이용한 부분방전 초음파 검출특성

이상훈,심승환,이광식,김달우 한국조명전기설비학회 2003 조명·전기설비학회논문지 Vol.17 No.4

It is well known that a partial-discharge(PD) in insulation oil is the source of various physical and chemical phenomena, such as heat, light, gas, chemical transformation, electric current, electromagnetic radiation and ultrasonics. The PD can be detected by measuring one of these changes. Although some techniques are employed in this purpose, several obstacles interfere with an on-line measurement. Ultrasonic-wave detection is a useful method for the diagnosis of the transformer-insulation condition. Conventionally, ulyrasonic waves are detected by Piezo-electric transducer, but we use optical method that has many advantages. In this paper, we constructed a Mach-Zehnder interferometer with optical fiber and investigated the principle of operation. Test arrangement is based on the needle-plane electrode system in oil and applied AC high voltage. Ultrasonic waves were detected and analyzed with wavelet transform. 본 논문에서는 유입변압기 진단을 목적으로 부분방전시 발생하는 여러 가지 물리적 화학적 현상중 초음파를 검출하기 위하여 광섬유 Mach-Zehnder 간섭계를 구성하였다. 구성된 광섬유 센서의 초음파 검출 평가 실험을 실시하고, 절연유 중에 배치한 침-평판전극에 교류 고전압을 인가하여 방전시 발생하는 초음파를 측정하고 퓨리에 변환 및 wavelet 변환을 이용한 데이터 분석 결과를 나타냈다.

회전 유리판과 3D 프린터를 이용한 교육용 마흐젠더 간섭계 제작

장성훈,주영구 한국광학회 2017 한국광학회지 Vol.28 No.5

This paper proposes how to fabricate an educational Mach-Zehnder interferometer that is easy to align and inexpensive, using3D printers and semiconductor lasers. The interferometer consists of a body 165 mm × 120 mm × 57 mm in size, mirror mounts,a laser holder, beam splitters, and so on. The laser path is adjusted by 4 mirror mounts, each comprised of rubber bands, smallmetal wires, and a screw. The interference fringe is enlarged by the lens at the final stage. The refractive index of a slide glasswas measured by counting the number of moving interference fringes while the slide glass, inserted into one of the twointerferometer arms, is rotating. The formula for the refractive index as a function of the optical-path difference and rotation anglewas obtained, and used to calculate the refractive index of glass from the interferometer experiment. The use of a rotating glassin one arm of the interferometer nullifies the need for a precision stage, which despite its high cost is often required to observethe moving interference fringe in the classroom. Therefore, the 3D-printed Mach-Zehnder interferometer proposed in this papercan be very useful for education, because of its affordability and performance. It enables students to perform both qualitativeand quantitative studies using a 3D-printed interferometer, such as measuring the refractive index of a glass sample, and thewavelength of light.

The Mach-Zehnder Interferometer Based on Silicon Oxides for Label Free Detection of C-reactive Protein (CRP)

홍종인,윤대성,김태송 한국바이오칩학회 2009 BioChip Journal Vol.3 No.1

The C-reactive protein (CRP) is a very important inflammation biomarker and a major predictor of cardiovascular disease (CVD) in human. We demonstrated here on a new approach to determine the binding of label free CRP to monoclonal anti-CRP using the Mach-Zehnder interferometer based on silicon oxides with the detection limit of 1 ng/mL or even less at the operating wavelength of 1,550 nm. The building block, single-mode waveguide of total internal reflection, was precisely designed using a finite element method (FEM) and so we suggested the guideline of microfabrication to achieve it. We also firstly introduced the calixcrown self-assembled monolayers (SAMs), which guaranteed the activity of capture proteins and the correct orientation, to immobilize the monoclonal anti-CRP on PECVD silicon oxides into the biosensors based on the interaction of the evanescent field of the guided light with the surrounding environment.

Sagnac 형태로 변형된 Mach-Zehnder 간섭계를 이용한 단일광자 간섭실험

엄자윤,김용수,김헌오,Um, Jayoon,Kim, Yong Soo,Kim, Heonoh 한국광학회 2012 한국광학회지 Vol.23 No.2

Sagnac 형태로 변형된 Mach-Zehnder 간섭계(SMZI)는 모든 광경로가 동일한 광부품을 서로 공유하기 때문에 위상 흔들림을 최소화할 수 있는 안정된 간섭계이다. 본 연구에서는 단일광자 수준까지 감쇄시킨 레이저 광과 제 2형의 매개하향변환에서 발생한 편광 상관관계가 있는 광자로부터 준비된 단일광자를 이용한 간섭실험에서 매우 안정된 간섭무늬를 관측하였다. SMZI의 위상은 약 ${\pm}0.18$ rad으로 안정적인 반면에 보통의 MZI는 ${\pm}1.02$ rad의 위상 요동을 나타내었다. A Sagnac-type Mach-Zehnder interferometer(SMZI) is a very stable instrument with respect to phase drift because all optical paths can share common optical components. We have observed very stable interference fringes in single photon interference experiments with an extremely attenuated laser beam, and with heralded single photons prepared from polarization correlated photon pairs in type-II spontaneous parametric down-conversion. The phase stability is measured to be about ${\pm}0.18$ rad for the SMZI, in contrast, conventional MZI showed the phase fluctuation of around ${\pm}1.02$ rad.

전계측정용 전기광학 Ti:LiNbO₃ Mach-Zehnder 집적광학 간섭기에 관한 연구

정홍식 大韓電子工學會 2011 電子工學會論文誌-SD (Semiconductor and devices) Vol.48 No.12

전계 측정시스템에서 센서 감지부로 1.3㎛ 파장에서 동작하는 대칭/비대칭 구조의 Mach-Zehnder 간섭기를 구현하였다. BPM 전산모사를 통해서 소자를 설계하였고, LiNbO₃에 Ti 확산방법으로 구현된 채널 광도파로에 집중 전극구조를 배열하여 집적광학 칩을 제작하였다. 대칭 구조로 위상차가 없도록 제작된 소자는 전기신호 200㎐, 1 ㎑ 구형 파형에서 반 파장전압 Vπ=6.6V, 변조 깊이 100%, 75%로 각각 측정되었다. 한편 π/2 위상차를 갖도록 설계된 비대칭 구조에서는 DC 0V에서 측정된 출력 광세기가 최고치에 약 1//2에 해당됨을 확인하였으며, 1㎑ 전기신호를 인가해서 π/2 위상차 때문에 나타나는 전기적 현상들을 확인하였다. Integrated-optic symmetric/asymmetric Mach-Zehnder interferometers at 1.3㎛ wavelength were studied as sensing part for electric-field measurement system. The devices were simulated based on the BPM software and fabricated utilizing Ti-diffused LiNbO₃ channel optical waveguides and lumped-type electrodes. A half-wave voltage of Vπ=6.6V and modulation depth of 100% and 75% for a symmetric structure were measured for 200㎐ and 1㎑ electrical signal bandwidth, respectively. By the way, almost half-maximum power transmission was observed for asymmetric interferometers with π/2 intrinsic phase difference. Expected experimental measurements were observed for 1㎑ electrical signal bandwidth.

실리카 도파로형 WDM 광 필터의 설계 및 해석에 관한 연구

최대필,문성욱,정영철,신장욱,정명영,최태구 광운대학교 신기술연구소 1997 신기술연구소논문집 Vol.26 No.-

본 논문에서는 Mach-Zehnder 간섭기로 구성된 1×4 필터와 성형결합기로 구성된 5×5 광도파로 격자 라우터를 BPM CAD TOOL을 이용하여 설계하였고 최적화 하였다. 마스크 레이아웃을 효율적으로 실현하기 위한 전체 도파구조를 설계하였다. BPM 전산모사를 통해 설계된 소자의 WDM 특성을 0.8 nm(100 ㎓)와 8.0 nm(1000 ㎓)의 채널간격에 대해서 살펴보았다. 설계된 소자는 두가지 채널간격 모두에 대하여 3.5dB 이내의 잉여손실, 0.5dB 이내의 균일성과 -22dB 이내의 누화(crosstalk)특성을 보임을 확인하였다. In this paper, we designed and optimized 1×4 WDM Filter composed of Mach-Zehnder Interferometer and 5×5 Waveguide Grating Router(WGR) composed of two star couplers. The overall guiding structure is designed to realize the mask layout efficiently. Through the BPM simulation, we demonstrated WDM characteristics of these devices with 0.8 nm and 8.0 nm channel-spacing. It is shown that the excess loss is less than 3.5dB, uniformity less than 0.5dB and the crosstalk smaller than –22 dB for both the channel spacings.

기계적으로 구현된 장주기 광섬유 격자 Mach-Zehnder 간섭계

장현수,조준용,이경식 한국광학회 2003 한국광학회지 Vol.14 No.4

본 논문에서는 장주기 광섬유격자쌍을 이용하여 광섬유 Mach-Zehnder 간섭계(MZI)를 기계적인 방법으로 구현해 보았다. 제작한 간섭계의 장주기 광섬유격자쌍의 투과스펙트럼과 fringe spacing의 이론치과 실험치를 비교, 분석해 보았다. 그 결과, fringe spacing의 값은 이론치와 실험치가 비교적 잘 일치하는 것을 알았다. We have demonstrated mechanically induced Mach-Zehnder interferometers (MZI) based on a long-period fiber grating pair. The transmission spectra, the interference fringes, and the fringe spacing of the long-period fiber grating pairs have also been investigated experimently and analytically. The fringe spacings of the fabricated LPG pairs agree well with the theoretical results.

전계측정용 전기광학 Ti:LiNbO_3 Mach-Zehnder 집적광학 간섭기에 관한 연구

정홍식 대한전자공학회 2011 電子工學會論文誌-SD (Semiconductor and devices) Vol.48 No.12

Integrated-optic symmetric/asymmetric Mach-Zehnder interferometers at 1.3㎛ wavelength were studied as sensing part for electric-field measurement system. The devices were simulated based on the BPM software and fabricated utilizing Ti-diffused LiNbO_3 channel optical waveguides and lumped-type electrodes. A half-wave voltage of V_π=6.6V and modulation depth of 100% and 75% for a symmetric structure were measured for 200㎐ and 1㎑ electrical signal bandwidth, respectively. By the way, almost half-maximum power transmission was observed for asymmetric interferometers with π/2 intrinsic phase difference. Expected experimental measurements were observed for 1㎑ electrical signal bandwidth. 전계 측정시스템에서 센서 감지부로 1.3㎛ 파장에서 동작하는 대칭/비대칭 구조의 Mach-Zehnder 간섭기를 구현하였다. BPM 전산모사를 통해서 소자를 설계하였고, LiNbO_3에 Ti 확산방법으로 구현된 채널 광도파로에 집중전극구조를 배열하여 집적광학 칩을 제작하였다. 대칭 구조로 위상차가 없도록 제작된 소자는 전기신호 200㎐, 1㎑ 구형 파형에서 반 파장전압 V_π=6.6V, 변조 깊이 100%, 75%로 각각 측정되었다. 한편 π/2 위상차를 갖도록 설계된 비대칭 구조에서는 DC 0V에서 측정된 출력 광세기가 최고치에 약 1//2에 해당됨을 확인하였으며, 1㎑ 전기신호를 인가해서 π/2 위상차 때문에 나타나는 전기적 현상들을 확인하였다.

Lithium Niobate (LiNbO3) Photonic Electric-Field Sensors

정홍식 한국센서학회 2022 센서학회지 Vol.31 No.4

This study comprehensively reviewed four types of integrated-optic electric-field sensors based on titanium diffused lithium-niobatewaveguides: symmetric and asymmetric Mach-Zehnder interferometers, 1×2 directional couplers, and Y-fed balanced-bridge Mach-Zehnder interferometers. First, we briefly explain the crystal properties and electro-optic effect of lithium niobate and the waveguidefabrication process. We theoretically analyzed the key parameters and operating principles of each sensor and antennas. We also describeand compare the design, simulation, implementation, and performance tests: dc and ac characteristics, frequency response, dynamicrange, and sensitivity. The experimental results revealed that the sensitivity of the sensor based on the Y-fed balanced bridge Mach-Zehnder interferometer (YBB-MZI) was higher than that of the other types of sensors.

The impact of raindrops on phase precision of Mach–Zehnder interferometer employing the coherent states and the squeezed vacuum states

Xie Duan,Li Zhe,Lei Teng,Liu Weihong 한국물리학회 2024 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.85 No.4

The paper explores the infuence of raindrops on the phase precision of Mach–Zehnder interferometer when the coherent states and the squeezed vacuum states are introduced into its input ports. The probability of photon loss η increases as the rain rate R or traveling distance L increases. In the presence of moderate or heavy rain, the loss probability η ranges from 0.2 to 0.48, or from 0.48 to 0.96 when the traveling distance L is close to 1 km. The threshold value Rth corresponds to the rain rate R at which the phase precision falls below the shot noise limit(SNL). At high squeezing level (r = arcsin h( √N∕2), the light rain does not degrade the phase precision below SNL. We also calculate the threshold value of rain rate(Rth) at various low levels of squeezing and compare Rth for three low squeezing levels (15 dB,10 dB, and 6 dB) that can currently be achieved. The results show that, at the same traveling distance, Rth is larger for a 15 dB squeezing level compared to 10 dB and 6 dB squeezing levels. Even in the presence of moderate rain, the phase precision for 15 dB remains sub-SNL for long distances approaching 1 km. A feasible experimental proposal for investigating the infuence of raindrops is put forward with the current technology.