• Korean Journal of Optics and Photonics
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• v.31 no.6
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• pp.259-267
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• 2020

We evaluate the degradation of receiver sensitivity induced by direct and indirect exposure to solar irradiance in free-space optical communication systems. For this purpose, we calculate the variances of numerous noise components arising from solar irradiance, and then estimate the receiver sensitivity penalties for intensity-modulation/direct-detection and coherent systems. The results show that the penalties are less than 1.3 dB when indirect sunlight impinges on the detector, regardless of the system. However, the sensitivity penalties are estimated to be larger than 30 dB when the sunlight is directly incident upon the receiver. These penalties are barely reduced if we insert an optical polarizer, or if we adjust the bandwidth of an optical filter at the receiver to be as narrow as the signal's bandwidth.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.163-168
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• 2003

The eye sensitivity in the difference conditions of a light source intensity consists of two functions by the receptor of cone and rod according to a wavelength. We derived a distribution function of $P{\lambda}=A{\cdot}e^{-({\lambda}-{\lambda}_u)^2/2W^2}$ using a respond probability of the receptor of cone-rod for a photon. It was well applied for a CIE eye's sensitivity curve of a wavelength. When there is lens In front of eye, luminous efficiency should be corrected. Transmission light which permeate to depends on absorption wavelength, and relationship of final luminous efficiency's estimation method is expressed by multiplication of luminous efficiency and transmittance intensity of lens. $$Pf({\lambda})=T({\lambda}){\cdot}P({\lambda})$$. The theory was applied to photopic and scopic vision with brown color lens.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.1
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• pp.133-138
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• 2015

A weight sensor with a polarization maintaining photonic crystal fiber (PCF) is proposed and investigated by experimentally. The sensor system consists of a 3 dB fiber coupler, a half-wave plate, and light source. Wavelength shift induced by weight acting on the polarization maintaining PCF was measured. Two types of sensor patterns, circle type and straight type, were implemented and evaluated. The sensitivity of straight line type was 680 pm/kg and the circle type was 270 pm/kg, respectively. The both types of sensors have a good sensitivity and good linearity in the wide range.

• The Journal of the Acoustical Society of Korea
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• v.19 no.2
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• pp.8-12
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• 2000

This paper describes the sensitivity stability of a mandrel type fiber optic acoustic sensor with respect to its environmental conditions such as hydrostatic pressure and underwater temperature. The sensors under consideration have various mandrel structures such as a cylindrical mandrel, a concentric composite mandrel, and an air-backed concentric composite mandrel. The analysis results show that the sensors have such good robustness, less than 0.15dB, in its sensitivity with respect to the variation in hydrostatic pressure. Further, the nylon concentric composite mandrel type sensor including an air cavity turns out to have the most superior stability than others to the underwater temperature variations.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.3
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• pp.349-356
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• 2015

Remote monitoring partial discharge sensor, equipping with hybrid filter combining optical and electrical noise reduction capabilities and with signal integrating function to calculate total arc energy, was investigated. Hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal integrating function showed selective detection capability corresponding to different arc energy levels, while convention arc sensor had difficulty to discriminate arc energy level due to bursty arc waveform and peak level detection characteristics. The sensor showed possibility for application to remote monitoring partial discharge sensor, since it detected arc energy level corresponding to normal open and close discharge in low voltage 100A MCCB at 2m distance.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.1
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• pp.47-56
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• 2009

Purpose: To find optimized luminosity factor of color from light transmission filter. Methods: To make $Y_{1-x}G_{x}$, $Y_{1-x}P_{x}$ by using CR-39 compound within dipping method, mixing up Y(Yellow), G(green) and P(pink) for optimize eye sensitivity. Modeling for relative luminous efficiency(relative sensitivity) curves in Luminose transmission, it could be resolved by Multiplying sensitivity of eye within transmission rate of Lens ($P_f({\lambda}=T({\lambda}){\cdot}P({\lambda}).)$.). To evaluate Wavelength between 400~700 nm, relative luminous efficiency curve in Area and Height value is being used. Results: In color filter of $Y_{1-x}G_{x}$ position of x equals to 0.04, 0.1, 0.08, 0.12, 0.14, 0.5 at ${\beta}=S_1/S_0{\cdot}100$ each consist value of 76.1, 77.9, 80.7, 81.6, 80.2, 18.6 In color filter of $Y_{1-x}P_{x}$ position of x equals to 1.00, 0.2, 0.6, 0.8 at ${\beta}=S_1/S_0{\cdot}100$ each consist value of 74.3, 74.0, 70.5, 33.0 The result from experiment $Y_{1-x}P_{x}$ value less than $Y_{1-x}G_{x}$, from evaluating luminous efficiency curve and test was successfully optimized. Conclusions: Optimized relative luminous efficiency curve result have value of X=0.12-0.14 at $Y_{1-x}G_{x}$.

• 전기의세계
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• v.46 no.12
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• pp.41-47
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• 1997

광감도 현상 그리고 여러가지의 광섬유 격자 제작 방법 및 광섬유 적용 분야에 대해서 고찰해 보기로 하자.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.218-223
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• 2016

This study examined the order of the Butterworth filter for the correlation on the sensitivity of the receiver in the receiver of an optical system. In the general case, the sensitivity of the receiver is increased if the order of the filter was increased more. This is because increasing the order of the filter response of the normalized frequency of the filter is similar to the rectangular wave. For that reason, the method used to increase the order of the filter increases the sensitivity of the receiver. On the other hand, a method of increasing the order of the filter and makes the system complicated increases the cost of the system. This study examined the correlation between the order of the sensitivity of the receiver filter and to configure the system by simply looking for ways to reduce the cost of the system. The simulation results showed that increasing the order of the filter resulted in a receiver that can determine if the sensitivity is raised. In addition, the order of the Butterworth filter range that does not reduce the sensitivity of the receiver was 2. Therefore, it will be possible to implement an inexpensive optical system of the receiver using the data from this study.

• Journal of Advanced Navigation Technology
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• v.9 no.2
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• pp.109-120
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• 2005

In this paper, bit error rate (BER) characteristics, sensitivity and minimum allowable launching power are numerically investigated as a function of amplifier spacing that consisted of 1,200 km WDM systems with MSSI method. It is conformed that the sensitivity and minimum allowable launching power are gradually degraded as amplifier spacings are gradually expanded, but those are not largely affected by modulation format. The sensitivity of RZ transmission system is smaller than that of NRZ transmission system, but minimum allowable launching power of NRZ transmission system is smaller than that of RZ transmission system. And, it is confirmed that the best amplifier spacing in NRZ and RZ transmission system is less than 50 km, because the sensitivity and minimum allowable launching power are less affected by fiber dispersion, channel wavelength and pump light power.

• Journal of the Korean Chemical Society
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• v.48 no.1
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• pp.39-45
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• 2004

Acid amplifying copolymers are synthesized by the copolymerization of tert-butyl methacrylate(tBMA) with acid-sensitive functional group and 4-hydroxy-4'p-styrenesufonyloxyisopropylidene dicyclohexane(HSI) or 4-p-styrenesulfonyloxy-4'-tosyloxyisopropylidenedicyclohexane(STI) with acid-amplifying group as novel polymeric acid amplifying photoresists. Poly(HSI-co-tBMA) film and Poly(STI-co-tBMA) film as acid amplifying photoresists show reasonable thermal stability in the absence of an acid species. Poly(STI-co-tBMA) film exhibits 2X higher photosensitivity, whereas Poly(HSI-co-tBMA) film show 2X lower photosensitivity compared with ptBMA homopolymer. The attachment of acid-amplifying units to polymer backbones could provide a novel way to enhance the photosensitivity of acid-sensitive polymers depending on the structure of acid-amplifying units.