| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 98 === This research demonstrates a simultaneous bidirectional WiMAX and NRZ signal over WDM-PON system design. The purpose is to use the existing fiber-optic transmission network architecture, but also provide an additional wireless transmission services to expand the scope and coverage network capacity by employing the wavelength dependent characteristics of electroabsorption modulator (EAM). When the C-band and L-band light source are injected into the EAM, C-band absorption modulator is better, as a downstream optical signal transmission. However, L-band absorption modulator is poor as the uplink modulated optical signal. So, we can utilize a reflective semiconductor optical amplifier (RSOA) nonlinear gain characteristics to work in the gain saturation, which can effectively suppress the residual interference signal modulation.
The system can achieve 5 MHz bandwidth WiMAX data with 2.665 GHz carrier frequency and 1.25 Gbps digital NRZ transmission for downstream transmission and also 5 MHz bandwidth WiMAX data with 2.675 GHz carrier frequency and 1.25 Gbps digital NRZ transmission for upstream signal. From these results, we have proved that simultaneous bidirectional WiMAX and NRZ signal over WDM-PON system can reduce a Rayleigh Back-Scattering efficiently and improve the EVM quality of wireless.
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