• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.1
• /
• pp.15-21
• /
• 2012

In this study, the characteristics of the 2-wavelength white organic light-emitting diod (WOLED) with two colors of yellow and blue were compared and analyzed with 3-wavelength WOLED with three colors of red, green, and blue. The results indicated that the power efficiency of the 2-wavelength WOLED was 1.6 times higher than 3-wavelength WOLED. In addition, the colot coordinate of the 2-wavelenth WOLED which was (0.34, 0.39) was found closer to the optimal color coordinate for the white-lighting application when compared with that of the 3-wavelength WOLED.

• Journal of Korean Institute of Industrial Engineers
• /
• v.26 no.4
• /
• pp.296-305
• /
• 2000

Virtual wavelength path (VWP) is the optical path when a wavelength conversion is possible in a wavelength division multiplexing (WDM) network that is transmission infrastructure for the next generation high speed backbone networks. To achieve efficient design for VWP networks, we must consider VWP routing, wavelength assignment, and wavelength conversion while satisfying many technical constraints of the WDM networks. In this study we propose an integrated model for efficient VWP design in WDM networks. We also develope a 3-phase algorithm, each of which deals with routing, wavelength assignment and route and wavelength reassignment, respectively. In our computational experiments, phase 1 algorithm can solve the problem to the optimality for medium size test networks. Phase 2 algorithm is an efficient heuristic based on a reduced layered network and can give us an effective wavelength assignment. Finally, phase 3 algorithm reconfigure VWP routing and its wavelength assignment to concentrate wavelength conversion nodes in the suggested VWP network.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.10
• /
• pp.29-33
• /
• 2010

In this paper, a new family of wavelength-time codewords using modified time mapped prime sequences as a time spreading pattern is constructed. When $P_t$ = 3, we can construct $P_w^2$ wavelength-time codewords with low autocorrelation sidelobe and crosscorrelation of less than or equal to 1. When $P_t$ = 5 and $P_t$ = 7, the number of wavelength-time codewords of $P_w^2$ can be constructed with good crosscorrelation of 1 and autocorrelation of less than or equal to 2.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.5
• /
• pp.1035-1040
• /
• 2009

We propose a new encoder/decoders based on an tune able wavelength converter(TWC) and an arrayed waveguide grating(AWG) router for large capacity optical CDMA networks. The proposed encoder/decoder treats codewords of wavelength/time 2-D code simultaneously using the dynamic code allocation property of the TWC and the cyclic property of the AWG router, and multiple subscribers can share the encoder/decoder in networks. Feasibility of the structure of the proposed encoder/decoder for dynamic code allocation is tested through simulations using two wavelength/time 2-D codes, which are the generalized multi-wavelength prime code(GMWPC) and the generalized multi-wavelength Reed-Solomon code(GMWRSC). Test results show that the proposed encoder/decoder can increase the channel efficiency not only by increasing the number of simultaneous users without any multiple-access interference but by using a relatively short length CDMA codes.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.6
• /
• pp.1117-1121
• /
• 2007

We demonstrate a wavelength swept mode-locked ring laser for the frequency domain optical coherence tomography(FD OCT). A laser is constructed by using a semiconductor optical amplifier, fiber Fabry-Perot tunable filter and 2.6 km fiber ring cavity. Mode-locking is implemented by 2.6 km fiber ring cavity for matching the fundamental or harmonic of cavity roundtrip time to a sweep period. The wavelength sweeps are repetitively generated with the repetition period of 77.2 kHz which is the parallel resonance frequency of Fabry-Perot tunable filter for the low driving current consumption of the fiber Fabry-Perot tunable filter. The wavelength tuning range of the laser is more than FWHM of 61 nm centered at the wavelength of 1320 nm and the linewidth of the source is $0.014{\pm}0.002$ nm.

• Korean Journal of Optics and Photonics
• /
• v.22 no.3
• /
• pp.129-133
• /
• 2011

Dual-wavelength holography has better axial range than single-wavelength holography, allowing unambiguous phase imaging but at the expense of increased noise. We have studied error reduction in dual wavelength holography using a modified fine map. The fine map is successful in measurement and has shown error reduction when the height of the object is less than the appled wavelength, but is unstable when the step height is larger than that wavelength. We have modified the fine map and we have found that the modified fine map was successful in measurement and error reduction even though the height of object was larger than the wavelength.

• Journal of Sensor Science and Technology
• /
• v.26 no.1
• /
• pp.28-34
• /
• 2017

An NIR grism Si optical area sensor spectrometer with in-band reference wavelength is designed and fabricated. It is composed of a transmission type diffraction grating (spatial density 300 line/mm), a rectangular N-BK7 prism (apex angle 30 degree), NIR filter(cutoff wavelength 720 nm), an imaging convex lens(focal length 50 mm F1.8) and an IR modified DSLR camera (Canon EOS40D) of Si optical area sensor ($3,888{\times}2,592$ pixels, pixel size $5.710{\mu}m$). "In-band reference wavelength function" is implemented using non-dispersive 0th diffraction order optical beam. The NIR grism spectrometer is tested in a laboratory using a halogen lamp and a Neon lamp. And the spectrometer is used in an astronomy field for obtaining the planet Jupiter NIR spectrum. In-band reference wavelength i.e. un-deviation wavelength is 846 nm, an wavelength resolution is 0.3027 nm/pixel, an wavelength resolving power is 2,794 and an wavelength range is 650~1,000 nm.

• Journal of the Optical Society of Korea
• /
• v.8 no.2
• /
• pp.55-58
• /
• 2004

Several internal wavelength locker schemes for 10 Gbps electro-absorption modulated laser EML) module were reviewed. 10 Gbps EML modules with simple and robust internal wavelength ockers for metro dense WDM application were successfully demonstrated. The wavelength aging ver 2000 hours was done at elevated temperature of 7$0^{\circ}C$. The average wavelength drift of 10 modules was measured to be about $\pm$ 5 pm. These modules can be successfully applied to the 0 Gbps DWDM systems with 50 ㎓ channel spacing.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.223.2-223.2
• /
• 2012

Grating spectrograph observation in near-infrared bands requires wavelength calibrations. We first need to extract order-strips from the echellogram data using flat images, and then to correct the spatial distortions and wavelength scales of the order strips using calibration arc lamps or the telluric OH emission lines. For very high resolution spectrograph using echelle, however, the arc lamps do not have enough emission lines in the order-strips, so we usually use the OH lines for accurate wavelength calibrations in wavelengths shorter than 2.3 microns. In this poster, we present wavelength calibration methods for longer wavelength bands using the telluric absorption lines in early-type stellar spectra and the telluric atmospheric transmission models. This technique will be applied to the data reduction pipeline for the IGRINS.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.34D no.6
• /
• pp.58-64
• /
• 1997

The wavelengt lockin gsystem of the optical fabry-perot filter theoretially derived and experimentally realized by using the ithering method in order to compensate the laser wavelength drift increasing the BER of the WDM system. The deviation between the laser wavelength and the optical filter center wavelength is compensated by applying a suitable voltage to the PZT. Accordingly, the laser wavelength selected by the fabry-perot filter always maintains the condition of maximum transmission powr. A wavelength locking system has been demonstrated using a fiber fabry-perot filter with a free spectral range of 80nm and an FWH of 1nm. The voltages of the sine wave generated for dithering was 20mV and 10mV, the frequency was 2kHz and center wavelength of the tunable laser was 1550nm. In this paper, the locking system have 20ms of locking time and 2nm of locking range.