Transmission impairments mitigation in next generation coherent optical access networks
Worldwide, the coherent technologies have revolutionized the optical communication systems, significantly increasing the capacity of the fiber channel owing to transmission of advanced modulation formats and effective mitigation of propagation impairments. However, the actual commercial solutions fo...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2021 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/672695 |
| Acceso en línea: | http://hdl.handle.net/10803/672695 https://dx.doi.org/10.5821/dissertation-2117-355668 |
| Access Level: | acceso abierto |
| Palabra clave: | Àrees temàtiques de la UPC::Enginyeria de la telecomunicació 621.3 |
| Sumario: | Worldwide, the coherent technologies have revolutionized the optical communication systems, significantly increasing the capacity of the fiber channel owing to transmission of advanced modulation formats and effective mitigation of propagation impairments. However, the actual commercial solutions for long-haul core/backbone networks are still complex and costly, and therefore hardly feasible for deployment in optical access networks. In particular, the main limitations arise from the customer premises equipment whose cost, footprint and power consumption may be kept down. Thus, the optimal solutions for next generation coherent optical access are required to achieve high performance but at lower complexity and cost, since in the access scenario the cost-effectiveness takes more relevance over achieving the best system performance. The research described in this thesis primarily aims at the development of the customer equipment “namely the coherent transceiver” for a passive optical access network that implements the novel wavelength-to-the-user concept by serving hundreds of users (e.g., 256 users) with dedicated wavelengths allocated in ultra-narrow optical grid. The proposed access network features complexity-reduced coherent technologies by leveraging photonic integration, commercial low-cost lasers and optics, and consumer electronics. To this end, the thesis investigates on the main transmission impairments that affect signal integrity from source to destination in the access network, and proposes novel and enhanced mitigation strategies by either low-complexity digital signal processing or analog hardware design. The covered topics spread over both the optical transmitter and the coherent receiver subsystems. Simplified optical modulation is addressed by direct phase modulation of semiconductor lasers profiting from the laser chirp. Digital pre-equalization of non-ideal frequency response from electronic/photonic devices “such as lasers, amplifiers and data converters” is investigated, focusing on the tolerance to quantization noise from digital-to-analog converters with limited resolution. Hardware-efficient strategies for optical carrier recovery based on differential phase detection are explored in two scenarios: homodyne receivers aided by digital signal processing, or fully analog heterodyne receivers. Finally, to deal with the critical polarization matching in coherent systems, simplified architectures for polarization-independent coherent receivers using low-cost optics and simpler receiver front-end are investigated. |
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