| Summary: | 碩士 === 國立中央大學 === 通訊工程研究所 === 93 === The implementation of fiber optic link with single wavelength is studied in this thesis. When a system was built, many employed components should be verified. Based on this purpose, the measuring benches of optoelectronic and radio frequency (RF) devices must be constructed for getting real parameters.
In the following topic, the standards of synchronous optical network (SONET) and global system for mobile communications (GSM) with Gaussian minimum shift keying (GMSK) modulation are described, because the implemented single wavelength fiber optic systems which operated in hybrid mode need a monitoring basis.
Using the verified components and standing on the standards of digital and modulated RF signals, a subcarrier modulation (SCM) system which comforted to SONET and GSM is implemented. The known broadband in spectrum of digital signal and the narrowband of carried GSM signal by RF tone are adopted, so how the microwave techniques applied to this system is our study goal. The estimating method of link which contains the electrical domains of transmitter and receiver, the electrical to optical (EO) conversion, the fiber channel, and the optical to electrical (OE) conversion, based on purely electrical simulator was also built in this topic.
Next, a Mach-Zehnder electrical to optical modulator (MZ-EOM or MZM) was analyzed. An analysis of electrical small signal model with varying optical large signal model was processed. According to this innovating definition, a double optical modulation (DOM) technique applied to implementation of SCM was proposed. The digital signal in optical domain and the modulated GMSK RF tone in electrical domain were directly combined by a MZ-EOM and simultaneously propagated through a fiber channel in a single wavelength window.
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