• Korean Journal of Optics and Photonics
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• v.19 no.6
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• pp.408-415
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• 2008

The characteristics of a ferroelectric-domain inverted grating fabricated by applying a high-voltage pulse at room temperature in Ti-diffused channel waveguides in z-cut $LiNbO_3$ (Ti:PPLN) were examined for channel waveguide quasi phase-matched secondharmonic generation devices. The fabrication conditions of uniform periodic domain-inversion were examined. Ti:PPLN with period ${\Lambda}=16.6{\mu}m$ for SHG were fabricated and the performances were measured. A normalized SHG efficiency as high as 473 (%/W) was obtained with 49 mm interaction length.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.4 s.304
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• pp.1-10
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• 2005

This paper presents a map matching method using multiple hypothesis technique(MHT) to identify the road that a land vehicle is located on. To realize a map matching method using MHT, Pseudo-measurements are generated utilizing adjacent roads of GPS/DR position and the MHT is reformulated as a single target problem. Since pseudo-measurements are generated using digital map, topological properties such as road connection, direction, and road facility information are considered in calculating probabilities of hypotheses. In order to improve the map matching performance under when bias errors exist in digital road map data, a Kalman filter is employed to estimate the biases. Field experimental results show that the proposed map matching method provides the consistent performance even in complex downtown areas, overpass/underpass areas, and in the areas where roads are adjacent in parallel.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.224-225
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• 2003

Since group velocity (GV) mismatch significantly limits the efficiency of nonlinear interactions such as second harmonic generation (SHG), several techniques have been developed to compensate GV mismatch. The simplest way to avoid the GV mismatch problem is to reduce the device length. However, it results in a poor trade-off between the SHG spectral bandwidth and the conversion efficiency. (omitted)