Abstract
In recent years, with the popularity of consumer electronics products and network usage, the data rate of signal transmission has been increasing exponentially. How to upgrade the hardware while remaining low cost is a challenge. Therefore, It is a hot topic to enhance the data rate on existing hardware. So that, the transiver cost of network users can be reduced. In this thesis, we explained the generation and reception of DDO-OFDM, the evolution of passive optical network (PON) and the advantage of OFDM PON. Then, the PON system was realized based on multi-band OFDM downstream and multi-band Nyquist QPSK upstream. In the PON system, we verified the Rayleigh backscattering (RBS) interferes between upstream and downstream signals if signals ware operated in the same frequency and fiber. Then, we proposed and demonstrated a model that could avoid RBS in a combined bi-directional system. By this system, eight channels WDM system has been realized. Beside, we demonstrated a passive polarization division multiplexing (PDM) receiving system, which can double the data rate in the existing PON system.