• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.3
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• pp.400-407
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• 1987

Thin film filter type 4-channel wavelength division multiplexing(WDM) device was designed and fabricated for the application in optical subscriber loop system. It has multi-mode fiber pigtails and four wavelength division consisting of 0.81, 0.89, 1.2 and 1.3 um. The evaluated performances are 1-2d B of insertion loss(connector loss excluded)and 30-35d B of crosstalk attenuation for all channels. The performance of the fabricated device was tested in the wideband optical transmission experiment, where the SNR degradation due to the crosstalk of the device was found to be within a measurement error.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05c
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• pp.21-23
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• 2004

We report experimental results demonstrating a novel metal defined polymer optical waveguide with a low loss in electro-optic polymers for the first time. The polymer optical waveguides are created using a metal film on the top of upper cladding without any conventional etching process. The fabricated waveguides have an excellent lateral optical mode confinement at both 1.31 ${\square}m$ and 1.55 ${\square}m$ wavelength, resulting in a fiber-to lens optical insertion loss of ~ 7 dB at 1.55 ${\square}m$ and ~4.5 dB at 1.31 ${\square}m$ wavelength in a 3.5cm total length for TM polarizations, respectively. We also present the optical loss dependence of the waveguide as a function of optical wavelengths. These results may be used in the complex design of integrated polymer optical circuits that need simpler and cheaper fabrication process.

• Electrical & Electronic Materials
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• v.9 no.10
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• pp.1047-1052
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• 1996

In this study, the thermal and optical proper-ties of multicomponent oxide glass fiber for IR sensor by adding heavy metal oxide Ga$_{2}$O$_{3}$ were investigated. The fiber samples were made by rod-in tube method. The optical loss of fiber was measured in 0.3-1.8/M wavelength region. As Ga$_{2}$O$_{3}$ increased up to 12wt%, the transition and softening temperature of bulk glass were increased from 495.deg. C to 564.deg. C and from 548.deg. C to 612.deg. C respectively. Whereas the thermal expansion coefficient was decreased from 102 to 88.2*10$^{-7}$ /.deg. C. The refractive index was increased from 1.621 to 1.662, and IR cut-off wavelength was enlarged from 4.64.mu.m to 5.22.mu.m. The optical loss of fiber was decreased and more remarkably decreased in 1.146.mu.m-1.8.mu.m wavelength region.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.477-479
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• 1997

The preparation of mach-zehnder inteferometric optical modulator and the properties of electrode and modulation bandwidth for high speed optical communications were described. The results of fabricated optical modulator was that optical 3-dB bandwidth 4.7GHz, driving voltage 6V and fiber-waveguide-fiber insertion loss 4.5dB for TM mode respectively.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.4
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• pp.867-871
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• 2012

In this paper, we proposed and demonstrated a low loss $1{\times}4$ type plastic optical fiber(POF) coupler incorporating a polymer tapering waveguide region. To avoid leakage loss at the interfaces between the POF and the polymer waveguide, we employed two POF transition regions, in which the cross section of the POF is adiabatically converted from a circular to a rectangular shape without change of its cross-section area. The device was fabricated based on a injection mold made of a silicon rubber. The fabricated POF coupler showed 1.33 dB of excess loss and 2.2 dB of flatness.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3A
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• pp.178-183
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• 2005

In Optical Burst Switching(OBS) networks, burst loss due to contention significantly affects the performance of networks. Even if many contention resolution schemes have been proposed, most of them have focused mainly on passively resolving contentions instead of avoiding them. In this paper, we propose an active contention avoidance scheme which controls a burst sending rate according to traffic load and burst loss in a network. Simulation results show that the proposed scheme can more effectively reduce the burst loss rate compared to existing OBS model with and without burst sending rate control, and at the same time guarantees throughput.

• Korean Journal of Optics and Photonics
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• v.15 no.6
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• pp.495-502
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• 2004

We proposed an analysis model for a Fabry-Perot cavity constructed with a plane-mirrored optical fiber and a concave-mirrored one. We presented the analysis results calculated by inserting practical values into the equations derived. The coupling loss of the cavity and the mirror loss are the most important parameters in reducing the insertion loss of the filter. In order to build a filter of finesse 600, FSR 57 nm, and insertion loss < 3 dB, the plane-concave cavity using mirrors of loss < 0.09% should be aligned for the coupling loss to be less than 0.1 %.

• ETRI Journal
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• v.30 no.6
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• pp.833-843
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• 2008

The effect of forward and reverse electrostatic discharge (ESD) on the electro-optical characteristics of oxide vertical-cavity surface-emitting lasers is investigated using a human body model for the purpose of understanding degradation behavior. Forward ESD-induced degradation is complicated, showing three degradation phases depending on ESD voltage, while reverse ESD-induced degradation is relatively simple, exhibiting two phases of degradation divided by a sudden distinctive change in electro-optical characteristics. We demonstrate that the increase in the threshold current is mainly due to the increase in leakage current, nonradiative recombination current, and optical loss. The decrease in the slope efficiency is mainly due to the increase in optical loss.

• Journal of the Korean Institute of Telematics and Electronics
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• v.18 no.3
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• pp.21-24
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• 1981

A simple optial fiber Y-branch is fabricated using micro - torch and fusion splicer. Tapered end of two fibers - in -contact is spliced with another fiber. Total insertion loss is 26dB and optical power branchi ng ratio is 0.98. Using fiber Y-branch, an UTDR with simple optical system is realized The resolution of the OTDR is $\pm$ 5m in length and t 0.5 dB/km in loss coefficient.