• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1112-1115
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• 1990

Described is a new control signal transmission system which utilizes an optical fiber to transmit 2-bit control signals from the transmitter to receiver. In the transmitter the DC series control voltages are converted into the multiple frequency signals by voltage controlled oscillator (VCO). The multiple frequency signals can easily be transmitted by optical fiber. In the receiver the multiple frequency signals can be detected by analog or digital circuits and then be converted into 2-state control signals which can be used for a variety of applications.

• ETRI Journal
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• v.9 no.2
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• pp.36-47
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• 1987

We have developed three types of muldexes; they are 140Mbit/s muldex, 565Mbit/s muldex and monitor & control muldex for a 565Mbit/s optical fiber transmission system. The frame format of our own type has been constructed for the M&C muldex, and new direct and parallel reframe techniques have been invented for 140Mbit/s, and 565Mbit/s muldex. Their functions, configurations and perform ance evaluations are described here.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.618-620
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• 1993

This system using optical fiber provides various information about underground tunnel and power transmission lines-atmospheric temperature, humidity, oil pressure, flammable gas, cable behavior, and so on. To transmit various data and to keep reliability, optical MUXs are adopted. User can easily operate monitoring software by using GUI.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.43-49
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• 2014

This paper presents a theoretical study of transmission performance for an optical duobinary transmitter employed a Mach-Zehnder modulator and a electrical low pass filter at 40Gbps optical communication links. It depends on the bandwidth of the low pass filter in the transmitter, the optical filter and the filter in the receiver. Also, each filter affected to the various parts of the optical power spectrum. By optimizing the bandwidth of each filter, we could control the side robes and the ripples and improve the dispersion tolerance of the transmission system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.9
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• pp.898-906
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• 2002

In this paper, we investigated the improvement degree of transmission distance of the various initial frequency chirped optical pulse with 5 dBm initial power dependence on the various bit rate and fiber dispersion coefficient, when MSSI(Mid-Span Spectral Inversion) with the optimal pump power condition is adopted for the compensation method for optical pulse distortion. And we analyzed the influence of mutual relation of optical pulse frequency chirp and Kerr effect on the MSSI methods for the long-haul optical transmission through the computer simulation. We found that the compensation degree of distorted optical pulse varies as a consequence of the variation of combined phase modulation of self phase modulation(Kerr effect) and initial frequency chirp parameter dependence on the fiber dispersion coefficient. And we found that, if the transmission bit rate is increased k times, the dispersion coefficient value of dispersion shift fiber is decreased $2^k$ times so as to be almost the same performance of the transmission system with k times lower bit rate.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1119-1122
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• 1990

Presnted is a new optical transmission system to transmit the FM control signal (80 MHz) through an optical fiber by the use of an inexpensive LED having a cutoff frequency of as low as 30 MHz. Studies are carried out on the division of the FM signal frequency at 80 MHz by a factor of four. The FM signal frequency is, after the transmission through the optical fiber, then multiplied by a factor of four so as to obtain the normal FM control signal.

• Journal of information and communication convergence engineering
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• v.19 no.4
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• pp.199-204
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• 2021

We propose a dispersion-managed link with a non-midway optical phase conjugator (OPC), in which the residual dispersion per span (RDPS) of each fiber span is different for each transmission section before and after OPC. We numerically demonstrate the compensation for 960-Gb/s wavelength-division multiplexed (WDM) signals distorted by chromatic dispersion and Kerr nonlinearity of the fiber. We consider different cases for non-midway OPC, including six fiber spans - OPC - 14 fiber spans and 14 fiber spans - OPC - 6 fiber spans. The numerical results show that the compensation of the distorted 960 Gb/s WDM is more efficient when the OPC is placed after 6-th fiber span as compared to after the 14-th fiber span. Our simulation results also indicate that the compensation effect increases when the difference in net residual dispersion between both transmission sections is not large, but they are not the same. Under this condition, the larger the magnitude of the RDPSs of each fiber span, the greater the compensation.

• Journal of information and communication convergence engineering
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• v.9 no.6
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• pp.753-757
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• 2011

The possibility of implementing nonuniform residual dispersion per span (RDPS) in optical links with net residual dispersion (NRD) controlled by precompensation and postcompensation for 960 Gbps WDM transmissions is studied and discussed. The fiber optic communication links investigated in this paper consist of inline dispersion management (DM) for each fiber spans and optical phase conjugator (OPC) at mid-way of total transmission length in order to compensate for WDM signal distortions due to group velocity dispersion (GVD) and nonlinearities. It is confirmed that the effect of nonuniform RDPS distribution on system performance is not significant. It is also confirmed that the optimal NRD is obtained to be one of two values of +10 ps/nm or -10 ps/nm, which depend on the deciding of NRD controlled by precompensation or postcompensation, and the exact RDPS configurations. The effective NRD ranges resulting eye opening penalty (EOP) below 1 dB are independent on the exact RDPS distribution for relative low launch power. Therefore, results show the possibility of implementing the flexible optical links to expand network construction for WDM transmission of high bit-rate capability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9B
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• pp.1542-1550
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• 2000

Fiber optic link systems based on SCM scheme are widely used as efficient and economic RF signal links between base station and a central station in mobile communication networks. However, its performance can be seriously limited depending on the operational conditions of not only the optical transmission system but also the wireless link in various environments. In this paper, we propose an analytic model for performance analyses of the SCM fiber optic link for CDMA RF signal transmission in various link environments. We present optimal operational conditions taking account of the nonlinear effects of the optical transmission system, and the multiple access interference produced at the wireless link. It has been shown through the BER analyses in this paper that the selection of optical modulation index of the SCM fiber optic links can be found optimally to minimize the fiber optic link noises and intermodulation distortion due to LD.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.547-556
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• 2016

A fishing lamp is the instrument for attracting distributed fish to a certain place, and is the lighting system mainly used in fishery. In the inshore fishing, most fishing lamps are used for squid and hairtail jigging fishing, and the light source of the fishing lamps mainly used is metal halide with 1.5 KW in electric power consumption. We will analyze the irradiance distribution according to depth because squid is attracted towards light. To analyze irradiance distribution by such fishing lamps, data for seawater Type-II among the seawater types defined in 1976 are applied to East Sea. However, the Type-II data have limitations in analyzing precise seawater transmission characteristics, due to insufficient information on deep seawater. This paper analyzed the irradiance distribution of fishing lamps using the measurement of transmission characteristics in the seawater in East Sea up to 100 m underwater instead of Type-II data, which is not sufficient for transmission. A compensation factor was drawn between the actual measurement data and Type-II data through seawater transmission characteristics simulation.