System performance of ASE injection seeded WDM-PON with optimized multilevel-OOK

Abstract

Wavelength division multiplexing passive optical network (WDM-PON) as a potential access network of next-generation communication system, has attracted extensive attentions from many outstanding researchers. ASE injection seeded WDM-PON is regarded as a promising fiber to the x (FTTx) system infrastructure owing to its cost-effective and color-free properties. However, this commercial system cannot directly employed for 10 Gb/s transmission due to the transmitter and receiver bandwidth limitation. Since we use ASE as the seed light, it is not easy to use some modulation formats that require coherent light, we focused on m-OOK to keep the ASE as the seed light. Compared to 2-OOK, m-OOK has a smaller mini-mum Euclidean distance that will definitely degrade the system performance, while requiring less bandwidth when transmit the same data rate signal makes m-OOK WDM-PON more resilient against the signal distortion induced by limited bandwidth, and also less stringent requirement of the modulation bandwidth may get rid of the usage of external modulator. In this thesis, we investigate multilevel-OOK (m-OOK) to overcome the limitation on transmitter and re-ceiver bandwidth. A conventional m-OOK with an equal distance between two adjacent levels has a poor per-formance due to signal dependent noise. We propose unequally spaced distance between levels in m-OOK to improve transmission performance. Both analytical and simulation methods are employed to investigate the influences of the injection power, the received power, the extinction ratio, the number of m-OOK signal levels, and also transmitter and receiver bandwidth on system performance of ASE injection seeded WDM-PON. We find that 4-OOK has a maximum bandwidth benefit of 4.5 GHz and 3.5 GHz to achieve the 1st and 2nd genera-tion FEC threshold compared with 2-OOK, respectively. And 3 GHz is the minimum required transmitter band-width to achieve the 2nd generation FEC threshold. In addition, the performance of pr...