• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.12
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• pp.1266-1273
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• 1991

Attenuation losses and repeater spans of single-mode optical fibers installed in the long hual optical transmission line were measured and analyzed. The average loss including splicing points was appeared to be 0.55 0.05dB/km and 0.59 0.01dB/km at 1300nm and 1550nm, respectively, and showed lager value at 1550nm window, The cause of loss increase at 1550nm range from the OTDR measurement was due to the inappropriate treatment of extra length of fiber at the splicing points. And average repeater span of domestic long haul line was 24 7km and 90% of total sampled repeater spans was within 31 km.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.425-427
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• 1997

Ti:LiNbO$_3$optical waveguides were fabricated as a function of Ti thickness and pigtailed with polarization maintaining fiber(PMF). The near field patterns and total insertion loss of these sample was showed and measured for optical wavelength 1550nm. The fiber-to-waveguide coupling loss was described also .

• Journal of information and communication convergence engineering
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• v.9 no.5
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• pp.551-555
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• 2011

Optical packet switching is a promising technology, which can integrate both data and optical network. In this paper, we present a comparative study of various traffic arrival approaches in WDM packet switches. The comparison is made based on packet loss rate and average delay under uniform and self-similar Pareto traffic. Computer simulations are performed in order to obtain the switch performance metrics. Study shows that burstiness of data traffic has a strong negative impact in the performance of WDM packet switches.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.7
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• pp.102-108
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• 1998

A new 1*4 optical waveguide power divider is proposed and fabricated. It consists of a 1*4 multi-branch structure with a beam separator and two beam expanders that can control the splitting ratios between the output ports. The proposed optical waveguide power divider is designed by employing the two dimensional finite difference beam propagation method and is fabricated by a reactive ion etching method. The splitting ratio of fabricatd device is 25.0 : 25.7 : 25.3 : 24.0 for TE mode and 25.7 : 25.2 : 24.1 : 25.0 for TM mode. Comapred with the conventional Y-branch structure, the proposed structure shortens the length of a 1*N divider by the factor 3. Thus it reduces the total propagation loss and the total radiation loss at the branch points. furthermore, the splitting ratios between the output ports may be controlled in this structure for some special applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10B
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• pp.1707-1713
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• 2000

We have proposed a tunable optical ADM using a fiber-optic transversal filter which is composed of fiber couplers and metal-film coated fiber-optic tapped delay-lines with a flat spectral response in abroad range of wavelength. Simulation results show that the optical loss at the DROP and PASS wavelengths of the OADM is negligible and the wavelength tunability is 0.78${\mu}{\textrm}{m}$/ps for the unit time delay of 2 ps. In order to investigate the effects of wavelength drift of the imput optical signal on the OADM the loss at the DROP port and the crosstalks to the other ports have been calculated. The maximum bit rates have been calculated at 46.26 Gb/s for the input Gaussian pulse width of 10 ps.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.593-596
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• 1997

The main purpose of this paper is to develop sensing device of joint angle using loss of opfical fiber. The source of light to optical fiber is infrared rays diode, and receiver is a photo transistor. The bent angle of optical fiber is measured with rotary encoder, and The change of voltage due to the loss of light is measured with micro computer PIC16C74. The sensing device may be used to Functional Electrical stimulation(FES) System for Rehabilitation patient.

• Macromolecular Research
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• v.12 no.5
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• pp.474-477
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• 2004

We present simple, low-cost methods for the fabrication of polymeric waveguides that have large core sizes for use as optical interconnects. We have used both hot embossing and micro-contact printing techniques for the fabrication of multimode waveguides using the same materials. Rectangular and large-core (60${\times}$60 $\mu\textrm{m}$$^2$) channels were readily prepared when using these methods. The dimensions of the embossed and printed channels were the same as those of the pattern on the original master. The polymeric waveguides that we fabricated with large core sizes exhibited a low propagation loss of 0.1 dB/cm at 850 nm, which indicates that hot embossing and micro-contact printing are suitable techniques for the fabrication of optical waveguides having large-core.

• ETRI Journal
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• v.27 no.4
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• pp.411-417
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• 2005

$Pr^{3+}-doped$ selenide glass optical fiber, which guarantees single-mode propagation of above at least 1310 nm, has been successfully fabricated using a Ge-Ga-Sb-Se glass system. Thermal properties such as glass transition temperature and viscosity of the glasses have been analyzed to find optimum conditions for fiber drawing. Attenuation loss incorporating the effects of an electronic band gap transition, Rayleigh scattering, and multiphonon absorption has also been theoretically estimated for the Ge-Ga-Sb-Se fiber. A conventional double crucible technique has been applied to fabricate the selenide fiber. The background loss of the fiber was estimated to be approximately 0.64 dB/m at 1650 nm, which can be considered fairly good. When excited at approximately 1470 nm, $Pr^{3+}-doped$ selenide fiber resulted in amplified spontaneous emission and saturation behavior with increasing pump power in a U-band wavelength range of 1625 to 1675 nm.

• Journal of Communications and Networks
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• v.9 no.3
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• pp.312-318
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• 2007

In this paper, we propose the optimal offset-time decision (OOD) algorithm which can effectively reduce the pre-transmission delay compared to the perfect isolation model, and can also be extended to general n priority classes while the target loss probability of each class is guaranteed for the variable offered load. In order to drive the OOD algorithm, we first analyze the loss probability of each priority class through class aggregation and iteration method; the analytic results obtained through the proposed algorithm are then validated with results garnered from extensive simulation tests.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.1906-1914
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• 2012

In this paper, relative service differentiation in JET based optical burst-switched networks with deflection routing is presented. It differs from conventional schemes in that it tries to make the loss rate of high class bursts as low as possible while maintaining the desired proportional ratio between the high class bursts and low class bursts. Strategies applied to it are dynamic wavelength allocation and the preemption which are combined to deflection routing. With dynamic wavelength allocation, the number of wavelengths allocated to high class bursts are dynamically changed. Preemption which gives more preference to high class bursts is also applied to decrease its loss rate. To lower the loss rate, deflection routing is applied for any kind of traffic. With those strategies, the suggested scheme shows desired properties that the loss rate of high class traffic is as lowered as possible. A queueing model for the scheme is developed to approximate loss ratio and the numerical results show that the proposed scheme provisions relative service differentiation.