Research On The Self-Seeding Technology In Passive Optical Network

In recent years, optical fiber communication technology develops rapidly, which greatly improved the transmission bandwidth of optical networks. Compared with optical core network which can support high-speed and large-capacity data transmission, optical access network becomes the main limitation to further enhance transmission rate. Therefore, passive optical network was put forward. Benefiting from its high speed, low cost of system maintenance and excellent transmission characteristics, PON has become the main study subject in future fiber access network development. To further reduce the cost of modulation of uplink signal in the optical network unite of PON, the self-seeding technology based on reflective semiconductor optical amplifier has been proposed. Compared with the laser modulation, this kind of self-seeding solution has low cost and colorless advantages. Therefore, more and more researchers focus on the self-seeding technology in recent years. How to further improve the quality of optical carrier, improve the speed of the uplink signal and reduce the uplink signal’s bit error rate are the main problems. In this paper, these issues are addressed.Firstly, for the RSOA-mirror self-seeding scheme, do research on the factors which affects the laser performance such as the length of laser cavity, dispersion, loss, filter’s bandwidth, which are discussed respectively. The VPI transmission Maker simulation has been built to study the impact of the related parameters on producing the self-seeding light, and the quality of the light was measured by the RIN. The laws of light performance has been found in the simulation. And based on the conclusion of the impact of the filter’s bandwidth, the new self-seeding structure including a FP-filter was proposed. This kind of structure can narrow down the 10-dB linewidth of the light with 4.5GHz compared with that produced by the self-seeding scheme which doesn’t contain a FP-filter.Secondly, the research was did on the direct modulation performance of the light produced by the RSOA-mirror self-seeding scheme with a FP-filter. The light produced by the self-seeding scheme with different parameters was modulated by the drive currents of the RSOA and the impacts on the performance of the OOK modulation and QAM was studied through measuring bit error rate, eye diagram and other various factors. The results of the simulations showed that under the same BER threshold the modulation rate of the light produced by the self-seeding scheme with a FP-filter was better than that without FP-filter in both 64QAM and OOK modulation.Finally, the experiment has been set up to measure the linewidth and side-mode suppression ratio in the situation of various currents of RSOA in the RSOA-mirror self-seeding structure. The quality of the light was compared between the back to back and the 10-kilometer-fiber transmission. The conclusion drawn in the simulation that increasing the drive currents can narrow down the linewidth was verifed.