• Title/Summary/Keyword: optical signal current

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Design and Implementation of Optical Signal Processor in Fiber-Optic Current Transducer for Electric Equipments (전력기기용 고안정성 광섬유 CT 센서의 광 신호처리기 설계 및 구현)

  • Jang, Nam-Young;Choi, Pyung-Suk;Eun, Jae-Jeong;Cheong, Hyeon-Seong
    • Journal of the Institute of Convergence Signal Processing
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    • v.8 no.3
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    • pp.171-177
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    • 2007
  • In this paper, we have designed and implemented an optical signal processor in order to use in a fiber-optic current CT for electric equipments where its properties were discussed. The fabricated optical signal processor is used to reduce a measurement current error that induced by the effects of intensity variation in the optical output signal due to losses coming from optical components or polarization variation in a PFOCS. Also, the optical signal processor was fabricated in compact/lightweight with unification of opto-electronic transducer part, analog signal process part, and real-time measurement part consisted of a level shift and ${\mu}-processor$. The experiment of optical signal processor has been performed in the range of $0{\sim}7,500A$ using the PFOCS made all fiber-optic components. As a result of experiment, the linearity error of measurement current is less than 1.7% and its average error is less than 0.3% in the range of $1,000A{\sim}7,000A$.

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A Study on Performance Improvement of Optical Current Transformer and Signal Processor (벌크형 광 CT 센서 및 신호처리부 성능 개선 방안 연구)

  • Kim, Young-Soo;Park, Byung-Seok;Kim, Myong-Soo;Lim, Yong-Hun
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.1929-1932
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    • 2002
  • In this paper, some parameters are studied for the performance improvement of a bulk optical current sensor. The performance of optical current sensor is influenced by current measuring range, Verdet constant change due to temperature change, temperature variation of wave plate, signal to noise ratio of optical transmitter/receiver, optical bias mismatch. Two types of optical current sensors are implemented and tested in the current range from 10 ampere to 200 ampere.

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A Comparison of Signal Processing Techniques in Optical Current Sensor for GIS

  • Kim, Young-Min;Park, Jung-Hwan;Jee, Seung-Wook;Lee, Kwang-Sik;Kim, Jung-Bae;Park, Won-Zoo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.9
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    • pp.103-109
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    • 2006
  • This research is contents about output characteristic of optic current sensor that use faraday effect. optic current sensor used in an experiment is consisted of three parts.(1) Source of light used laser diode of 1310[nm].(2) Sensor section manufactured circularly according to gas insulated switchgear. And $9/125[{\mu}m]$ standard single mode optical fiber for communication was installed winding 20 [turn] on sensor section core surroundings of diameter 31 [cm].(3) Electrical signal of PD(Photo detector) is collected using NI company's 16bit DAQ board via terminal block. Collected data analyzed by different three signal processing methods. NI company's $Labview^{TM}$ was used to signal processing software. As a result, In signal processing of optic current sensor, we could know that noise greatly more influences the error generation than fluctuation of light intensity. also, 1 class CT(current transformer) manufacture that have error rate less than 1[%] was available by removing these

Design and Fabrication of Si pin photodiode for APF optical link (APF optical link용 Si pin photodiode의 설계 및 제작)

  • 강현구;남정식;이지현;김윤희;이상열;김장기;장지근
    • Proceedings of the IEEK Conference
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    • 2000.06b
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    • pp.270-273
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    • 2000
  • We have fabricated and analyzed photodiodes for optical link with Si pin structures. As the results of experiment, the web patterned photodiode(type C) with $p^{+}$-guard ring showed low junction capacitance of 6~7 pF at $V_{R}$=-5V and high separation ability for optical signal(dark current : $\leq$ 5 nA, optical signal current : $\geq$ 340 nA) due to the small effective $p^{+}$-n junction area and the expanded electric field region. The fabricated Si pin photodiode can be applicable for detecting an optical signal with the wavelength of about 660~670 nm. It can also be integrated with the twin well CMOS structure to develope an one chip based optical receiver IC. IC.C.

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Experimental Evaluation of Frequency Characteristics of Gain-saturated EDFA for Suppression of Signal Fluctuation in Terrestrial Free-space Optical Communication Systems

  • Yoo Seok, Jeong;Chul Han, Kim
    • Current Optics and Photonics
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    • v.7 no.1
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    • pp.28-32
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    • 2023
  • Frequency characteristics of gain-saturated erbium-doped fiber amplifier (EDFA) are experimentally evaluated to mitigate the optical signal fluctuation induced by atmospheric turbulence in terrestrial freespace optical communication systems. Here, an acousto-optic modulator (AOM) is used to emulate optical signal fluctuations induced by atmospheric turbulence. The waveform which is generated in proportion to the refractive-index structural parameters is used to drive the AOM at various periodic frequencies. Thus, the dependence of the signal fluctuation suppression on the frequency is evaluated. The experiment is conducted using a periodic frequency sweep of the AOM driving voltage waveform and signal input power variation of the amplifier. It is observed that a low periodic frequency and high input signal power effectively suppress the optical signal fluctuation. This study evaluates the experimental results from the high-pass filter and gain-saturation characteristics of the EDFA.

Optical Signals Using Superposition of Optical Receiver Modes

  • Lee, Jae Seung
    • Current Optics and Photonics
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    • v.1 no.4
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    • pp.308-314
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    • 2017
  • A particular optical receiver has its own optical receiver modes (ORMs) determined by its optical and electrical filters. Superposing the ORM waveforms at the transmitter, we can generate a new type of optical signals, called ORM signals. After optical detection, they produce pre-specified voltage waveforms accurately, which is advantageous for digital signal processing. Assuming a Gaussian optical receiver, where the optical and electrical filters are Gaussian, we illustrate various phase-shift keying ORM signals using two ORMs by changing their relative phase. We also illustrate multi-level ORM signal patterns using two or more ORMs.

Depleted Optical Thyristor using Vertical-Injection Structure for High Isolation Between Input and Output (완전공핍 광 싸이리스터에서 입출력의 높은 아이솔레이션을 위한 수직 입사형 구조에 관한 연구)

  • Choi Woon-Kyung;Kim Doo-Gun;Moon Yon-Tae;Kim Do-Gyun;Choi Young-Wan
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.1
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    • pp.30-34
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    • 2005
  • This study shows the lasing characteristics of InGaAs/InGaAsP multiple-quantum-well waveguide-type depleted optical thyristor (DOT) using the vertical window. The measured switching voltage and current are 3.36 V and 10 ㎂, respectively. The lasing threshold current is 131 mA at 25 ℃. The output peak wavelength is 1570 nm at a bias current of 1.22 Ith and there is not input signal anymore in the output port. The vertical injection depleted optical thyristor - laser diode (VIDOT-LD) using the vertical-injection structure shows very good isolation between input and output signal.

Fiber Fabry-Perot type Optical Current Transducer with Frequency Ramped Signal Processing Scheme

  • Park, Youn-Gil;Seo, Wan-Seok;Lee, Chung-E.;Taylor, Henry-F.
    • Journal of the Optical Society of Korea
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    • v.2 no.2
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    • pp.74-79
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    • 1998
  • The use of a fiber Fabry-Perot interferometer (FFPI) as an optical current transducer is demonstrated. A conventional inductive pickup coil converts the time-varying current I(t) being measured to a voltage waveform V(t) applied across a piezeolectric strip to which the FFPI is bonded. The strip experiences a longitudinal expansion and contraction, resulting in an optical phase shift ${\phi}(t)$ in the fiber proportional to V(t). This phase shift is measured using a frequency-modulated semiconductor light source, photodiodes to monitor the reflected light from the FFPI and the laser power, and a digital signal processor. Calibration routines compute V(t) and I(t) from the measured phase shift at a l KHz rate. Response to 60 Hz ac over the design range 0-1300A rms is characterized Transient response of the FFPI transducer is also measured.

Research on the Influence of Polarization Aberration on Heterodyne Efficiency in Space Coherent Laser Communication System

  • Zheng, Yang;Piao, Yu
    • Current Optics and Photonics
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    • v.6 no.1
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    • pp.23-31
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    • 2022
  • Heterodyne efficiency is an indicator to evaluate the performance of space coherent laser communication systems. It is affected by signal light and local oscillator (LO) light amplitude, phase and polarization state. In this paper, based on the common heterodyne efficiency, a heterodyne efficiency model that can reflect polarization aberration of optical system is proposed. The heterodyne efficiency is analyzed when the signal light and the LO light are linearly polarized or circularly polarized. For a coherent communication optical system, when the incident signal light is right-circularly polarized light and the incident LO light is 45° linear polarized light. Based on the three-dimensional ray tracing theory and the heterodyne efficiency proposed in this paper, the change of polarization states and the distribution of heterodyne efficiency of the signal light and LO light influenced by the optical system's polarization aberration are analyzed. Analysis shows that the heterodyne efficiency model proposed in this paper can be used to evaluate coherent communication systems and reflect the influence of optical system polarization aberration.

Development of Optical Signal Transmission for the KSTAR Project Pertaining to Instrumentation and Control of the Neutral Beam Test Stand at KAERI

  • Jung, Ki-Sok;Oh, Byung-Hoon
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.5B no.3
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    • pp.289-295
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    • 2005
  • Instrumentation and Control (I&C) of the Neutral Beam Test Stand (NB- TS) Facility at the Korea Atomic Energy Research Institute (KAERI) for the Korea Superconducting Tokamak Advanced Research (KSTAR) project has been underway since the start of the project to answer the diverse requests arising from the various facets of the development and construction phases of the project. Optical signal transmission constitutes a significant portion of I&C works and has been performed for the entirety of the project. During the NB- TS construction and related experiments, significant achievements to a more accurate as well as more refined optical signal transmissions have been made. Examples of those I&C works that utilized the optical signal transmission are the Langmuir probe signal transmission, gradient grid current signal transmission, gas flow control and signal transmission, ion source temperature measurement, beam line component temperature monitoring, and coolant flow signal transmission, etc. These optical signal transition provisions are now performing part of the indispensable functions for the proper operation of the NB- TS facility. Attained experience and expertise are expected to be well applied to the upcoming main neutral beam injection (NBI) system construction for the KSTAR project.