#### Optical subcarrier label switching using nonlinear harmonic modilation in external mach-zehnder modulator = Mach-zehnder 광변조기의 비선형 하모닉 변조 특성을 이용한 광부캐리어 레이블 교환 방법

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All-optical label switching networks require a simple and effective method to swap optical headers in real time without affecting payload data in order to realize low-latency packet forwarding and routing. An optical subcarrier multiplexed (OSCM) optical header attatched to each optical packet can be processed and replaced using relatively low-speed optoelectronics, while the high-speed payload data easily separated from the optical header data remains transparently in the optical domain. This dissertation proposes a novel method to generate the $2^{nd}$ harmonic subcarrier (2$\omega_{sc}$) multiplexed optical header signals and detect the optical headers without RF fading effects from interaction between the double-sideband (DSB)-OSCM header signal and the optical payload signal. By separating the $2^{nd}$ harmonic DSB-OSCM optical header signal from the combined signal with a conventional fiber Bragg grating filter at the receiver node, we can detect the optical header by a simple square law detector. The proposed scheme is validated by numerical analysis, simulation and finally by experiments. We first derive an analytic expression for the $2^{nd}$ harmonic optical subcarrier label signal. We can generate the conventional $1^{st}$ harmonic DSB-OSCM signal and the $2^{nd}$ harmonic DSB-OSCM signal by adjusting the bias voltage of external MZ intensity modulator. Next, we simulate the proposed $2^{nd}$ harmonic DSB-OSCM using VPITransmissionMaker. From the simulation study, we obtain the optimum modulation depth of header signals and improve receiver sensitivity. To confirm the proposed scheme experimentally, optical spectra before and after an FBG filter are compared. BER measurements also show that the header power penalties are maintained within 0.5 dB against $\plusmn$0.04nm wavelength shifts of the fiber Bragg grating filters center frequency. Our scheme is proved to be robust under environmental change. From several experiments, it is confirm...
Won, Yong-Hyubresearcher원용협researcher
Description
한국정보통신대학교 : 공학부,
Publisher
한국정보통신대학교
Issue Date
2007
Identifier
392810/225023 / 000995426
Language
eng
Description

학위논문(박사) - 한국정보통신대학교 : 공학부, 2007.2, [ xiii, 106 p. ]

Keywords

RF mixer; transmitter configuration; modulation format; WDM; optical communications; CSRZ; 광섬유 비선형 현상; 주파수 효율; 믹서; 송신기 구조; 광신호 변조방식; 파장다중; 광통신 시스템

URI
http://hdl.handle.net/10203/54588