• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.12
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• pp.31-44
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• 1996

Since optical delay line signal processing which utilizes optical fiber as delay line elements can provide high speed and broadband signal processing, the optical delay line signal processing has numerous applications. Recently, many research papers which optical delay line signal processing techniques are being applied to OCDMA are published. The author has published paper on the design method for optical fiber filters of lattice structure. However, the previous design method does not realize the transfer function all the time. It can be realized with constraints. In this paper, we propose the design method that can realize the transfer function all the time without any constraints for the optical fiber filter of lattice structure.

• Proceedings of the Optical Society of Korea Conference
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• 1999.08a
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• pp.116-117
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• 1999

Optical fiber networks for microwave signal processing have been investigation . Theoretical and experimental results are presented in Z-shaped Double-Coupler Optical Resonator. The use of Mason's rule to calculate transfer functions greatly simplified the analysis in our model. A good comparison between modelling and experiment is presented.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.3
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• pp.239-248
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• 2004

Optical coherence tomography(OCT) is high resolution imaging system which can see the cross section of microscopic organs in the living tissue. In this paper, we analyze the relation between the light source and the resolution of modulated signal in Michelson interferometer. We construct 1-D OCT signal processing hardware such as amplifiers, filters, and demodulate electronic signals from the photo detector. In order to get 2-D OCT image, the synchronization among optical delay line, sample stage and A/D converter is dealt with. In experiments, we verify analog and digital signal processing blocks which apply to the stacks of glasses. Finally we aquire high resolution 2-D OCT image with respect to the onion tissue. We expect that this result can be applied to the medical instrument through performance improvement.

• Journal of Sensor Science and Technology
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• v.20 no.2
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• pp.107-113
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• 2011

LSPR(Localized Surface Plasmon Resonance) sensor measures the refractive index change on the sensor surface. The detection of biological reaction with the unknown refractive index needs to be converted into the signal sensitivity for the refractive index change for comparison with other measurements. To find the signal sensitivity, the three steps of signal processing are proposed, which are signal modeling, signal calibration and signal normalization of LSPR sensor. The detected signal of biotin-streptavidin interaction has been converted into unit of [RU](Resonance Unit) using the proposed method. The converted signal directly can be compared with the other sensors including commercialized one.

• Journal of the Optical Society of Korea
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• v.4 no.2
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• pp.89-93
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• 2000

Recently a new signal processing algorithm for white light interferometry was presented. In this paper, the proposed signal processing algorithm was applied for absolute temperature measurement using white light interferometry. Stability testing and absolute temperature measurement were demonstrated. Stability test demonstrated the feasibility of absolute temperature measurement with an accuracy of 0.015 fringe. The test also showed that the absolute temperature measurement system using white light interferometry is capable of obtaining the theoretical minimum detectable change (0.0005 fringe), which is consistent with the performance predicted by the proposed signal processing algorithm.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.11
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• pp.1481-1488
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• 1995

Due to the low loss, broadband and accurate short time delay properties of optical fiber, it has attracted as a delay medium for high speed and broad-band signal processing. In this paper, we consider the coherent optical fiber filter of IIR lattice structure, which uses coherent light sources and consists of directional couplers whose coupling coefficients are restricted between 0 and 1. Considering restrictions of directional coupler, the design formulae and condition for realibility of optical fiber filter of IIR lattice structure which makes the optimal use of optical signal energy are derived.

• 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 $1,000A{\sim}7,000A$.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.12a
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• pp.145-148
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• 2000

Position-determining capacity is a very important condition in equipments for manufacturing semi-conductor or various instruments to measure physical displacement quantities of a moving object in submicron such as a distance of movement, direction, etc. and the accuracy of total system is influenced by detecting accuracy of these equipments. Therefore in this paper we have optically made up laser linear encoder based on optical diffraction principle to measure these displacement quantities and have processed optical signal using hardware-setup. In consequence we had acquired displacement for movement of scale using a diffraction grating by the accuracy of 0.5${\mu}{\textrm}{m}$ and had digitalized moving quantities of scale.

• 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.

• Current Optics and Photonics
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• v.2 no.5
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• pp.413-421
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• 2018

We propose a novel methodology based on the multiplication function to improve the signal-to-noise ratio (SNR) for vibration detection in a phi optical time-domain reflectometer system (phi-OTDR). The extreme-mean complementary empirical mode decomposition (ECEMD) is designed to break down the original signal into a set of inherent mode functions (IMFs). The multiplication function in terms of selected IMFs is used to determine a vibration's position. By this method, the SNR of a phi-OTDR system is enhanced by several orders of magnitude. Simulations and experiments applying the method to real data prove the validity of the proposed approach.