{"id":{"repo_id":"cork","oai_identifier":"oai:cora.ucc.ie:10468/18807"},"canonical_url":"https://search.dev.ndltd.org/etd/cork/oai:cora.ucc.ie:10468/18807","repository":{"repo_id":"cork","name":"University College Cork","base_url":"https://cora.ucc.ie/server/oai/request"},"display":{"title":"SOA enhanced optical line terminal for future optical access network","abstract":"Future passive optical networks (PONs) aim to deliver data rates of 100 Gb/s per wavelength using intensity-modulation direct detection (IM/DD) and up to 400 Gb/s per wavelength using coherent technology. Achieving these targets requires overcoming the large dynamic range of burst-mode upstream packets, typically around 20.5 dB, caused by differential loss between optical network units (ONUs). Conventional burst-mode receivers rely on transimpedance amplifiers (BM-TIAs) that adjust electrical gain for each burst, but their limited linearity and bandwidth restrict scalability to higher speeds. As IM/DD systems approach and exceed 100 Gb/s per wavelength, they also struggle to meet the 29 dB optical power budget defined by the International Telecommunication Union (ITU-T) G.9804 standard. Coherent transmission is therefore seen as a promising solution for extending PON capacity, offering superior receiver sensitivity, higher spectral efficiency, and inherent chromatic dispersion tolerance. This thesis investigates Semiconductor Optical Amplifier (SOA)-based optical burst power equalisation as a promising approach to dynamic range management across both IM/DD and coherent PON architectures. By regulating optical gain before photodetection, SOA-based equalisation mitigates gain saturation effects, suppresses nonlinear distortions, and reduces the need for complex digital signal processing. Two novel techniques are developed and experimentally demonstrated: (A) variable bias and (B) control light injection. Both methods achieve a 24 dB dynamic range in 100 Gb/s 4-level pulse amplitude modulation (PAM4) burst-mode transmission with bit error rates below the soft-decision forward error correction threshold using a simplified low-gain receiver. The optical-domain equalisation concept is further extended to coherent PONs employing dual-polarisation 16-quadrature amplitude modulation (DP-16QAM). In this case, a low-power local oscillator (LO) configuration is implemented to demonstrate compatibility with potential comb-source-based architectures. This design relaxes the wavelength alignment requirement between the ONU and the LO, addressing one of the main challenges in coherent PONs where ONU wavelengths can drift by a few nanometers. SOA gain control enhances linearity and enables high-fidelity burst detection without requiring fast BM-TIAs. These findings show that SOA-based equalisation eliminates the need for high-gain BM-TIAs, thereby preventing bandwidth, gain, and dynamic range limitations associated with the TIA in both coherent and IM/DD systems. Furthermore, the results demonstrate that complex digital signal processing is unnecessary to achieve high dynamic range using an SOA preamplifier, and that simple linear equalisation is sufficient to compensate for low-cost 25G-class receiver bandwidth limitations and moderate fibre dispersion in IM/DD systems. To explore manufacturable integration, a transfer-printed SOA preamplifier is demonstrated for the first time in a 100 Gb/s PON context, confirming its potential for scalable, and low-cost receiver designs. Overall, this work establishes SOA-based optical power equalisation as a key enabler for next-generation high-speed PONs. It provides a pathway to support 100 Gb/s IM/DD and 400 Gb/s coherent operation while maintaining high dynamic range, receiver sensitivity, and system simplicity, enabling fully integrated, energy-efficient, and cost-effective optical access networks.","abstract_html":"Future passive optical networks (PONs) aim to deliver data rates of 100 Gb/s per wavelength using intensity-modulation direct detection (IM/DD) and up to 400 Gb/s per wavelength using coherent technology. Achieving these targets requires overcoming the large dynamic range of burst-mode upstream packets, typically around 20.5 dB, caused by differential loss between optical network units (ONUs). Conventional burst-mode receivers rely on transimpedance amplifiers (BM-TIAs) that adjust electrical gain for each burst, but their limited linearity and bandwidth restrict scalability to higher speeds. As IM/DD systems approach and exceed 100 Gb/s per wavelength, they also struggle to meet the 29 dB optical power budget defined by the International Telecommunication Union (ITU-T) G.9804 standard. Coherent transmission is therefore seen as a promising solution for extending PON capacity, offering superior receiver sensitivity, higher spectral efficiency, and inherent chromatic dispersion tolerance. This thesis investigates Semiconductor Optical Amplifier (SOA)-based optical burst power equalisation as a promising approach to dynamic range management across both IM/DD and coherent PON architectures. By regulating optical gain before photodetection, SOA-based equalisation mitigates gain saturation effects, suppresses nonlinear distortions, and reduces the need for complex digital signal processing. Two novel techniques are developed and experimentally demonstrated: (A) variable bias and (B) control light injection. Both methods achieve a 24 dB dynamic range in 100 Gb/s 4-level pulse amplitude modulation (PAM4) burst-mode transmission with bit error rates below the soft-decision forward error correction threshold using a simplified low-gain receiver. The optical-domain equalisation concept is further extended to coherent PONs employing dual-polarisation 16-quadrature amplitude modulation (DP-16QAM). In this case, a low-power local oscillator (LO) configuration is implemented to demonstrate compatibility with potential comb-source-based architectures. This design relaxes the wavelength alignment requirement between the ONU and the LO, addressing one of the main challenges in coherent PONs where ONU wavelengths can drift by a few nanometers. SOA gain control enhances linearity and enables high-fidelity burst detection without requiring fast BM-TIAs. These findings show that SOA-based equalisation eliminates the need for high-gain BM-TIAs, thereby preventing bandwidth, gain, and dynamic range limitations associated with the TIA in both coherent and IM/DD systems. Furthermore, the results demonstrate that complex digital signal processing is unnecessary to achieve high dynamic range using an SOA preamplifier, and that simple linear equalisation is sufficient to compensate for low-cost 25G-class receiver bandwidth limitations and moderate fibre dispersion in IM/DD systems. To explore manufacturable integration, a transfer-printed SOA preamplifier is demonstrated for the first time in a 100 Gb/s PON context, confirming its potential for scalable, and low-cost receiver designs. Overall, this work establishes SOA-based optical power equalisation as a key enabler for next-generation high-speed PONs. It provides a pathway to support 100 Gb/s IM/DD and 400 Gb/s coherent operation while maintaining high dynamic range, receiver sensitivity, and system simplicity, enabling fully integrated, energy-efficient, and cost-effective optical access networks.","abstract_has_math":false,"creators":["Jamali, Fariba"],"institution":"University College Cork","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Townsend, Paul D.","Antony, Cleitus"],"committee_chairs":[],"committee_members":[],"year":2026,"date_issued":"2026-02-28","date_published":"2026-02-28","updated_at":"2026-07-24T01:47:31Z","subjects":["PON","SOA","Optical equalisation","Next generation","Burst-mode","CPON","Integrated SOA"],"languages":["en"],"rights":["© 2026, Fariba Jamali."],"rights_urls":["https://creativecommons.org/licenses/by-nc-nd/4.0/"],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/10468/18807","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Townsend, Paul D.","Antony, Cleitus"]},{"key":"dc:creator","label":"Author","values":["Jamali, Fariba"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2026-05-21T13:20:16Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2026-05-21T13:20:16Z"]},{"key":"dc:date.issued","label":"Date","values":["2026-02-28"]},{"key":"dc:publisher","label":"Institution","values":["University College Cork"]},{"key":"dc:type","label":"Dc Type","values":["Doctoral thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["PhD - Doctor of Philosophy"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["PON","SOA","Optical equalisation","Next generation","Burst-mode","CPON","Integrated SOA"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["© 2026, Fariba Jamali."]},{"key":"dc:rights.uri","label":"Rights URI","values":["https://creativecommons.org/licenses/by-nc-nd/4.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10468/18807"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Future passive optical networks (PONs) aim to deliver data rates of 100 Gb/s per wavelength using intensity-modulation direct detection (IM/DD) and up to 400 Gb/s per wavelength using coherent technology. Achieving these targets requires overcoming the large dynamic range of burst-mode upstream packets, typically around 20.5 dB, caused by differential loss between optical network units (ONUs). Conventional burst-mode receivers rely on transimpedance amplifiers (BM-TIAs) that adjust electrical gain for each burst, but their limited linearity and bandwidth restrict scalability to higher speeds. As IM/DD systems approach and exceed 100 Gb/s per wavelength, they also struggle to meet the 29 dB optical power budget defined by the International Telecommunication Union (ITU-T) G.9804 standard. Coherent transmission is therefore seen as a promising solution for extending PON capacity, offering superior receiver sensitivity, higher spectral efficiency, and inherent chromatic dispersion tolerance. This thesis investigates Semiconductor Optical Amplifier (SOA)-based optical burst power equalisation as a promising approach to dynamic range management across both IM/DD and coherent PON architectures. By regulating optical gain before photodetection, SOA-based equalisation mitigates gain saturation effects, suppresses nonlinear distortions, and reduces the need for complex digital signal processing. Two novel techniques are developed and experimentally demonstrated: (A) variable bias and (B) control light injection. Both methods achieve a 24 dB dynamic range in 100 Gb/s 4-level pulse amplitude modulation (PAM4) burst-mode transmission with bit error rates below the soft-decision forward error correction threshold using a simplified low-gain receiver. The optical-domain equalisation concept is further extended to coherent PONs employing dual-polarisation 16-quadrature amplitude modulation (DP-16QAM). In this case, a low-power local oscillator (LO) configuration is implemented to demonstrate compatibility with potential comb-source-based architectures. This design relaxes the wavelength alignment requirement between the ONU and the LO, addressing one of the main challenges in coherent PONs where ONU wavelengths can drift by a few nanometers. SOA gain control enhances linearity and enables high-fidelity burst detection without requiring fast BM-TIAs. These findings show that SOA-based equalisation eliminates the need for high-gain BM-TIAs, thereby preventing bandwidth, gain, and dynamic range limitations associated with the TIA in both coherent and IM/DD systems. Furthermore, the results demonstrate that complex digital signal processing is unnecessary to achieve high dynamic range using an SOA preamplifier, and that simple linear equalisation is sufficient to compensate for low-cost 25G-class receiver bandwidth limitations and moderate fibre dispersion in IM/DD systems. To explore manufacturable integration, a transfer-printed SOA preamplifier is demonstrated for the first time in a 100 Gb/s PON context, confirming its potential for scalable, and low-cost receiver designs. Overall, this work establishes SOA-based optical power equalisation as a key enabler for next-generation high-speed PONs. It provides a pathway to support 100 Gb/s IM/DD and 400 Gb/s coherent operation while maintaining high dynamic range, receiver sensitivity, and system simplicity, enabling fully integrated, energy-efficient, and cost-effective optical access networks."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["SOA enhanced optical line terminal for future optical access network"]}]}],"canonical_facts":{"dc:contributor.advisor":["Townsend, Paul D.","Antony, Cleitus"],"dc:creator":["Jamali, Fariba"],"dc:date.accessioned":["2026-05-21T13:20:16Z"],"dc:date.available":["2026-05-21T13:20:16Z"],"dc:date.issued":["2026-02-28"],"dc:description.abstract":["Future passive optical networks (PONs) aim to deliver data rates of 100 Gb/s per wavelength using intensity-modulation direct detection (IM/DD) and up to 400 Gb/s per wavelength using coherent technology. Achieving these targets requires overcoming the large dynamic range of burst-mode upstream packets, typically around 20.5 dB, caused by differential loss between optical network units (ONUs). Conventional burst-mode receivers rely on transimpedance amplifiers (BM-TIAs) that adjust electrical gain for each burst, but their limited linearity and bandwidth restrict scalability to higher speeds. As IM/DD systems approach and exceed 100 Gb/s per wavelength, they also struggle to meet the 29 dB optical power budget defined by the International Telecommunication Union (ITU-T) G.9804 standard. Coherent transmission is therefore seen as a promising solution for extending PON capacity, offering superior receiver sensitivity, higher spectral efficiency, and inherent chromatic dispersion tolerance. This thesis investigates Semiconductor Optical Amplifier (SOA)-based optical burst power equalisation as a promising approach to dynamic range management across both IM/DD and coherent PON architectures. By regulating optical gain before photodetection, SOA-based equalisation mitigates gain saturation effects, suppresses nonlinear distortions, and reduces the need for complex digital signal processing. Two novel techniques are developed and experimentally demonstrated: (A) variable bias and (B) control light injection. Both methods achieve a 24 dB dynamic range in 100 Gb/s 4-level pulse amplitude modulation (PAM4) burst-mode transmission with bit error rates below the soft-decision forward error correction threshold using a simplified low-gain receiver. The optical-domain equalisation concept is further extended to coherent PONs employing dual-polarisation 16-quadrature amplitude modulation (DP-16QAM). In this case, a low-power local oscillator (LO) configuration is implemented to demonstrate compatibility with potential comb-source-based architectures. This design relaxes the wavelength alignment requirement between the ONU and the LO, addressing one of the main challenges in coherent PONs where ONU wavelengths can drift by a few nanometers. SOA gain control enhances linearity and enables high-fidelity burst detection without requiring fast BM-TIAs. These findings show that SOA-based equalisation eliminates the need for high-gain BM-TIAs, thereby preventing bandwidth, gain, and dynamic range limitations associated with the TIA in both coherent and IM/DD systems. Furthermore, the results demonstrate that complex digital signal processing is unnecessary to achieve high dynamic range using an SOA preamplifier, and that simple linear equalisation is sufficient to compensate for low-cost 25G-class receiver bandwidth limitations and moderate fibre dispersion in IM/DD systems. To explore manufacturable integration, a transfer-printed SOA preamplifier is demonstrated for the first time in a 100 Gb/s PON context, confirming its potential for scalable, and low-cost receiver designs. Overall, this work establishes SOA-based optical power equalisation as a key enabler for next-generation high-speed PONs. It provides a pathway to support 100 Gb/s IM/DD and 400 Gb/s coherent operation while maintaining high dynamic range, receiver sensitivity, and system simplicity, enabling fully integrated, energy-efficient, and cost-effective optical access networks."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["https://hdl.handle.net/10468/18807"],"dc:language.iso":["en"],"dc:publisher":["University College Cork"],"dc:rights":["© 2026, Fariba Jamali."],"dc:rights.uri":["https://creativecommons.org/licenses/by-nc-nd/4.0/"],"dc:subject":["PON","SOA","Optical equalisation","Next generation","Burst-mode","CPON","Integrated SOA"],"dc:title":["SOA enhanced optical line terminal for future optical access network"],"dc:type":["Doctoral thesis"],"dc:type.qualificationlevel":["Doctoral"],"dc:type.qualificationname":["PhD - Doctor of Philosophy"]},"updated_at":"2026-07-24T01:47:31Z"}