Wavelength-hopping and time-spreading optical CDMA systems : new coding and implementation technologies = 파장 및 시간 영역의 분산을 이용하는 광 CDMA 시스템new coding and implementation technologies

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When an optical CDMA network is implemented by traditional methods, an optical code is preferentially selected, and then an optical source and a tunable encoder are designed to generate the code. In this case, the components designed to generate preselected code may have large loss and complicated structure, and then resulted performance is degraded, because the preselected code doesn’t take account of hardware optimization. This thesis describes effective design and implementation of wavelength-hopping and time-spreading (WH-TS) optical CDMA networks, in which new technologies to overcome above problems are proposed. The new technologies provide the reversed design procedure that the required components as well as the network are first designed, and then optical codes are generated by the adaptation procedure for fully utilization of preselected hardware and resultant high performance. The proposed optical CDMA system comprises a modified figure-of-eight fiber laser (MF8L) as an optical source, a tunable encoder using fixed delay lines (FDLs), and an adaptive resonance code (ARC). Experimental results of the proposed simple MF8L show that the optical pulses from the MF8L satisfy all requirements in a WH-TS optical CDMA source such as broadband spectrum (26 nm), high-power (over 1 kW peak power), and short pulse-width (0.79 ps). The novel tunable encoder consists of an arrayed waveguide grating (AWG), switches, and FDLs instead of tunable delay lines (TDLs) that make the system complex and cause large loss during the encoding process. The proposed tunable encoders are therefore implemented using fewer elements and causes lower loss (at least 17 dB) than those using TDLs. The ARC is generated by the optimization program to minimize multiple access interference (MAI) as well as to adapt to arbitrary restrictions such as code length, the number of wavelength, and weight (the number of pulses) that arise from designing WH-TS optical CDMA networks, and implement...
Advisors
Won, Yong-Hyubresearcher원용협researcher
Description
한국정보통신대학교 : 공학부,
Publisher
한국정보통신대학교
Issue Date
2004
Identifier
392423/225023 / 000985842
Language
eng
Description

학위논문(박사) - 한국정보통신대학교 : 공학부, 2004, [ xi, 170 p. ]

Keywords

Wavelength-hopping; Time-spreading optical CDMA systems; Implementation technologies; New coding

URI
http://hdl.handle.net/10203/54531
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=392423&flag=dissertation
Appears in Collection
School of Engineering-Theses_Ph.D(공학부 박사논문)
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