Operation Characteristics Of The Monolithically Integrated EML-SOA

Electroabsorption Modulated Laser(EML), which is a monolithic integration of the Distributed Feedback(DFB) semiconductor laser and Electroabsorption Modulator(EAM), is one of the key devices in the optical fiber access network. However, the improvement of the transmission distance and splitting raito of the network is substantially limited by the insert loss and positive chirp generated in the EAM section. Integration of a Semiconductor Optical Amplifier(SOA) with EML(EML-SOA) might be an effective solution to this problem, as SOA can not only boost the optical power, but also generate negative chirp for chirp compensation and optimization. However, the integrated SOA would also introduce amplified spontaneous emission noise and enhance the optical feedback, which have huge impacts on the output properties of EML. This thesis focuses on the impact of the integrated SOA to the output properties of EML, and the main contents are as follows:(1) The theoretical models of DFB?EAM and SOA are studied. Then the simulation codes is developed to discuss the performance of the each individual device. Based on the models of individual device, a model of the integrated device is established which can realize joint simulation of three different devices, which laids a solid foundation for the researching of the performance of EML-SOA.(2) The influences of the integrated SOA to the output properties of EML is analyzed The research is mainly focused on three different operation states, which includes single mode state with the Side Mode Suppression Ratio(SMSR) higher than 30 d B, self-pusation state and multi-modes state, for the EML-SOA with different facet reflections and DFB/SOA section biases. Especially, the phase modulation effect of SOA which is one of the main causes that degrade the performance of EML-SOA is deeply discussed. And then the tolerance of EML-SOA with the bulk and QW DFB/SOA sections to the optical feedback in is compared.(3) The highest facet reflections of the EML-SOA for the single mode operation with SMSR bigger than 30 d B, is searched when grating phases at the ends of DFB section change in the range from 0 to 2?. Based on the results obtained, yield of EML-SOA during mass production is then discussed for different reflection level at the end facets.(4) The chirp characteristic of EML-SOA is investigated. The compensation effects of SOA section to the positive chirp of EAM section are discussed.