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The Study of Externally Modulated AM Video Lightwave Transmitter

Abstract
In this thesis, we use a high power 1550 nm DFB laser and
a Ti:LiNbO3 Mach-Zehnder modulator to construct an externally
modulated trensmitter for CATV lightwave system. We use two
methods to reduce the problem caused by stimulated Brillouin
scattering (SBS) effect in externally modulated AM video system
by using high-frequency phase modulation and low-frequency
dithering techniques. In this experiment, the SBS threshold can
be increased by 6 dB. We also design a automatic gain control
(AGC) circuit with a 10 dB dynamic range in our transmitter.
After addition with a home-made predistortion linearized circuit,
the system performance of this transmitter in a 20 km single-mode
fiber link carrying 60 NTSC channels can be achieved with a
CNR¡Ù46~52 dB¡BCSO¡Ø-68~-73 dBc¡BCTB¡Ø-59~-63 dBc. As the number of
channels increased from 60 to 80, we can obtain CNR¡Ù46~51 dB,
CSO¡Ø-65.5~-71 dBc, and CTB¡Ø-55~-60.4 dBc. According to preceding
description, we know that our trensmitter can carry 60 ~ 80 NTSC
channels.

Identiferoai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0627100-050426
Date27 June 2000
CreatorsLin, Hsien-Sheng
ContributorsTao-Yuan Chang, Yuang-Kuang Chen, Wood-Hi Cheng, Yin-Chieh Lai, Yuan-Kuang Tu
PublisherNSYSU
Source SetsNSYSU Electronic Thesis and Dissertation Archive
LanguageCholon
Detected LanguageEnglish
Typetext
Formatapplication/pdf
Sourcehttp://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0627100-050426
Rightswithheld, Copyright information available at source archive

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