Final Report Summary - ARTISTE (Advanced Regenerator Technologies for high Capacity Systems)
The project ARTISTE was focused on training activities with a significant effort on the development of all-optical signal regeneration approaches to unlock the capacity of future information systems by enabling transmission of highly spectral efficient signal formats beyond their linear Shannon limits. The key objectives of the project include scientific training in non-linear techniques in optical transmission, photonic device technologies, advanced modelling methods to enable the fellow become a research leader in the field of optical communications. In addition, the project included training in soft-skills such as IP protection, communication skills and management skills.
The training programme of ARTISTE encompassed two basic training elements for the Fellow, i.e. i) Research Skills and Knowledge and ii) Complementary Skills. The Research Skills and Knowledge aspect of training was focused on diversifying and complementing the existing research knowledge and skills of the fellow by providing him with a range of specialist training in: T1. high performance computing, T2. Test and measurement techniques for advanced signal formats, T3. non-linear long haul transmission, T4. Photonic device fabrication. The Complementary Skills training module is focused on the development of additional competencies that will be fundamental for the professional maturity of the Fellow, namely S1. project management skills, S2. financial management skills, S3. networking skills, S4. organizational skills, S5. supervisory teaching skills, S6. proposal preparation, S7. knowledge, management and commercialization, S8. personal transferable skills.
The training objectives were covered by the nine tasks of Work-Package 1. Within this work package the fellow had the opportunity to attend courses offered by the ASTON Human Resources on the effective planning and time and financial management of research projects. Furthermore he had the opportunity to exercise further his management skills by undertaking the responsibility of managing the ARTISTE project, without any intervention of his supervisory team and increasing his involvement in the management duties two other ICT projects. In parallel, the Fellow had the opportunity to cultivate his networking skills by attending the largest conference in the field of optical communications. Specifically, he attended the European Conference in Optical Communications (ECOC) that took place in London. In the second year, i.e. Sept 2014, he also attended the European Conference in Optical Communications (ECOC) that took place in Cannes. Also, he attended the Advanced Photonics conference that took place in Boston USA, as an invited speaker. Finally, he organized a workshop on optical regeneration, which took place in ASTON. These events gave to the Fellow the opportunity to meet important people in the field coming either from academia or industry. AIPT is also a place where prominent researchers in photonic technology from all over the world visit to give lectures. The Fellow most of the time was introduced to these people and he was having the opportunity for a face-to-face discussion on potential scientific collaborations. ASTON was for the Fellow a unique environment to build his supervisory and teaching skills. After receiving appropriate training on the “Effective mentoring” offered by the ASTON HR department, the fellow had the opportunity to enhance further his supervisory experience by coaching 1 PhD student and two other young researchers, who had recently received a PhD title. Furthermore, he undertook teaching duties by performing tutorial courses on mathematics for the 1st year engineers in the school of electrical engineering and applied science.
One of the most important skills that the fellow had the opportunity to extensively develop during his fellowship was on preparation of research proposals. Specifically, the fellow was engaged in the preparation of more than 8 submitted research grants in various european calls, with 3 of them being accepted (i.e. the MCs INVENTION, STOLAS, HSPACE). Furthermore he attended courses offered by experienced European project research managers at ASTON university. His writing skills have been enhanced by preparing several research papers, whereas his presentation skills by giving talks in international conferences. Finally, through his continuing collaboration with the members of his supervisory team the fellow had the opportunity to develop all the critical scientific skills that are required for completing the research goals of his project.
The training objectives of the project are covered by Work Package-1 (WP-1). Within this WP the Fellow has received during the duration of the project training seminars from the Human Resources of ASTON in project management and he had the opportunity to exercise further his relevant skill-set by undertaking responsibilities on actual research projects. In parallel, he attended world leading conferences in optical communications and he has been acquainted with renowned researchers in the field. ARTISTE project has provided also a unique opportunity to the Fellow to cultivate his academic skills in teaching and supervision, by delivering undergraduate-level tutorial courses in mathematics at the School of Applied Science and supervising PhD level students. In parallel, the training he received on proposal writing, already at the 1st year of the project, has been essential to him for preparing a research grant application.
The research objectives of the project take place within Work-package 2 (WP-2). This consisted of five tasks that covered all the development aspects of future regenerative subsystems, from device fabrication to network application. The main experimental achievement of the Fellow, during the duration of the project have been the development of the first multi-channel PSA based regenerator for dual quadrature signals (i.e. QPSK), which comprised a novel carrier extraction and phase synchronization scheme. The regenerator has been implemented using optimized highly non-linear fibre devices which have been fabricated by one of the industrial partners (OFS) of the project. Furthermore the Fellow has designed and experimentally implemented the first all-optical add-drop multiplexer for OFDM signals. This research activity deviated from the original goals of the project but it was the Fellow's decision to explore this research path due to the high importance of the topic. His decision proved right, as his work was highly rated in the largest European Conference in Optical Communications (ECOC), leading also to an invited paper in the prestigious journal of Lightwave Technology (IEEE) as well as to additional invitations in international conferences. Apart from the experimental work the Fellow, has also carried out significant theoretical work on the design of regenerative systems. Along with Dr. Mariia Sorokina he has extensively investigated the transmission performance of nonlinear regenerative channels based on cascaded PSAs and they have explored the impact of the phase and amplitude noise accumulation mechanisms in the selection of the optimum modulation format. Furthermore they have worked on the development of an analytical technique to define, in terms of a single transfer function parameter the optimum conditions and operating margins of cascaded PSA based regenerators in multi-level phase encoded transmission links. Rigorous numerical simulations have been carried out to confirm the analytical prediction of the theory revealing also the performance dynamics along the cascaded system. It has been found that all-optical regeneration brings significant performance gain to the system, when moving to large signal complexities, but reduces the operating margins. In this direction, extensive work has been carried out in the design of novel regenerator concepts for advanced modulation formats. More specifically, they have proposed a novel NOLM based configuration for regenerating rectangular QAM signals. The scheme achieves suppression of noise distortion on both signal quadratures through the realization of two orthogonal regenerative Fourier transforms. Numerical simulations illustrated a successful cascadability performance for the case of 4-, 16- and 256 QAM signals.
Of significant importance was the work of the fellow on the 3R based regeneration. In the past, a full 3R functionality (i.e. re-amplification, re-shaping, re-timing) was essential for the regenerative subsystems which had to deal with the prevailing return to zero (RZ) modulated signals. However, with the recent introduction of highly spectral efficient signals, characterized by non-return to zero (NRZ) modulation of complex constellations (i.e. m-QAM), the re-timing functionality was overlooked and the efforts were focused on advancing only the 2R performance, through schemes that could remove the noise from the multiple amplitude and phase levels of the signal waveform. However, in future transmission systems the channels will be densely packed and tight filtering will be required for any in-line channel selection, e.g. to perform all-optical add-drop multiplexing or signal regeneration. Unavoidably, this will give rise to timing jitter effects that will accumulate along the 2R line and drastically limit the system cascadability. During his fellowship the researcher developed a new regeneration scheme for highly spectral efficient formats and through numerical simulations they have proved the necessity of the scheme against traditional 2R solutions for future high capacity systems.
Apart from the core research work in the ARTISTE project the Fellow had also the opportunity to provide scientific contributions to additional research activities that were running in parallel in the optical communication lab. During the duration of the project the Fellow achieved 31 publications in high impact factor scientific journals and international conferences.
The training programme of ARTISTE encompassed two basic training elements for the Fellow, i.e. i) Research Skills and Knowledge and ii) Complementary Skills. The Research Skills and Knowledge aspect of training was focused on diversifying and complementing the existing research knowledge and skills of the fellow by providing him with a range of specialist training in: T1. high performance computing, T2. Test and measurement techniques for advanced signal formats, T3. non-linear long haul transmission, T4. Photonic device fabrication. The Complementary Skills training module is focused on the development of additional competencies that will be fundamental for the professional maturity of the Fellow, namely S1. project management skills, S2. financial management skills, S3. networking skills, S4. organizational skills, S5. supervisory teaching skills, S6. proposal preparation, S7. knowledge, management and commercialization, S8. personal transferable skills.
The training objectives were covered by the nine tasks of Work-Package 1. Within this work package the fellow had the opportunity to attend courses offered by the ASTON Human Resources on the effective planning and time and financial management of research projects. Furthermore he had the opportunity to exercise further his management skills by undertaking the responsibility of managing the ARTISTE project, without any intervention of his supervisory team and increasing his involvement in the management duties two other ICT projects. In parallel, the Fellow had the opportunity to cultivate his networking skills by attending the largest conference in the field of optical communications. Specifically, he attended the European Conference in Optical Communications (ECOC) that took place in London. In the second year, i.e. Sept 2014, he also attended the European Conference in Optical Communications (ECOC) that took place in Cannes. Also, he attended the Advanced Photonics conference that took place in Boston USA, as an invited speaker. Finally, he organized a workshop on optical regeneration, which took place in ASTON. These events gave to the Fellow the opportunity to meet important people in the field coming either from academia or industry. AIPT is also a place where prominent researchers in photonic technology from all over the world visit to give lectures. The Fellow most of the time was introduced to these people and he was having the opportunity for a face-to-face discussion on potential scientific collaborations. ASTON was for the Fellow a unique environment to build his supervisory and teaching skills. After receiving appropriate training on the “Effective mentoring” offered by the ASTON HR department, the fellow had the opportunity to enhance further his supervisory experience by coaching 1 PhD student and two other young researchers, who had recently received a PhD title. Furthermore, he undertook teaching duties by performing tutorial courses on mathematics for the 1st year engineers in the school of electrical engineering and applied science.
One of the most important skills that the fellow had the opportunity to extensively develop during his fellowship was on preparation of research proposals. Specifically, the fellow was engaged in the preparation of more than 8 submitted research grants in various european calls, with 3 of them being accepted (i.e. the MCs INVENTION, STOLAS, HSPACE). Furthermore he attended courses offered by experienced European project research managers at ASTON university. His writing skills have been enhanced by preparing several research papers, whereas his presentation skills by giving talks in international conferences. Finally, through his continuing collaboration with the members of his supervisory team the fellow had the opportunity to develop all the critical scientific skills that are required for completing the research goals of his project.
The training objectives of the project are covered by Work Package-1 (WP-1). Within this WP the Fellow has received during the duration of the project training seminars from the Human Resources of ASTON in project management and he had the opportunity to exercise further his relevant skill-set by undertaking responsibilities on actual research projects. In parallel, he attended world leading conferences in optical communications and he has been acquainted with renowned researchers in the field. ARTISTE project has provided also a unique opportunity to the Fellow to cultivate his academic skills in teaching and supervision, by delivering undergraduate-level tutorial courses in mathematics at the School of Applied Science and supervising PhD level students. In parallel, the training he received on proposal writing, already at the 1st year of the project, has been essential to him for preparing a research grant application.
The research objectives of the project take place within Work-package 2 (WP-2). This consisted of five tasks that covered all the development aspects of future regenerative subsystems, from device fabrication to network application. The main experimental achievement of the Fellow, during the duration of the project have been the development of the first multi-channel PSA based regenerator for dual quadrature signals (i.e. QPSK), which comprised a novel carrier extraction and phase synchronization scheme. The regenerator has been implemented using optimized highly non-linear fibre devices which have been fabricated by one of the industrial partners (OFS) of the project. Furthermore the Fellow has designed and experimentally implemented the first all-optical add-drop multiplexer for OFDM signals. This research activity deviated from the original goals of the project but it was the Fellow's decision to explore this research path due to the high importance of the topic. His decision proved right, as his work was highly rated in the largest European Conference in Optical Communications (ECOC), leading also to an invited paper in the prestigious journal of Lightwave Technology (IEEE) as well as to additional invitations in international conferences. Apart from the experimental work the Fellow, has also carried out significant theoretical work on the design of regenerative systems. Along with Dr. Mariia Sorokina he has extensively investigated the transmission performance of nonlinear regenerative channels based on cascaded PSAs and they have explored the impact of the phase and amplitude noise accumulation mechanisms in the selection of the optimum modulation format. Furthermore they have worked on the development of an analytical technique to define, in terms of a single transfer function parameter the optimum conditions and operating margins of cascaded PSA based regenerators in multi-level phase encoded transmission links. Rigorous numerical simulations have been carried out to confirm the analytical prediction of the theory revealing also the performance dynamics along the cascaded system. It has been found that all-optical regeneration brings significant performance gain to the system, when moving to large signal complexities, but reduces the operating margins. In this direction, extensive work has been carried out in the design of novel regenerator concepts for advanced modulation formats. More specifically, they have proposed a novel NOLM based configuration for regenerating rectangular QAM signals. The scheme achieves suppression of noise distortion on both signal quadratures through the realization of two orthogonal regenerative Fourier transforms. Numerical simulations illustrated a successful cascadability performance for the case of 4-, 16- and 256 QAM signals.
Of significant importance was the work of the fellow on the 3R based regeneration. In the past, a full 3R functionality (i.e. re-amplification, re-shaping, re-timing) was essential for the regenerative subsystems which had to deal with the prevailing return to zero (RZ) modulated signals. However, with the recent introduction of highly spectral efficient signals, characterized by non-return to zero (NRZ) modulation of complex constellations (i.e. m-QAM), the re-timing functionality was overlooked and the efforts were focused on advancing only the 2R performance, through schemes that could remove the noise from the multiple amplitude and phase levels of the signal waveform. However, in future transmission systems the channels will be densely packed and tight filtering will be required for any in-line channel selection, e.g. to perform all-optical add-drop multiplexing or signal regeneration. Unavoidably, this will give rise to timing jitter effects that will accumulate along the 2R line and drastically limit the system cascadability. During his fellowship the researcher developed a new regeneration scheme for highly spectral efficient formats and through numerical simulations they have proved the necessity of the scheme against traditional 2R solutions for future high capacity systems.
Apart from the core research work in the ARTISTE project the Fellow had also the opportunity to provide scientific contributions to additional research activities that were running in parallel in the optical communication lab. During the duration of the project the Fellow achieved 31 publications in high impact factor scientific journals and international conferences.