Periodic Reporting for period 1 - ReSOLeS (New Reconfigurable Spectrum Optical Fibre Laser Sources)
Reporting period: 2019-05-01 to 2021-04-30
Optical lasers are extraordinary light sources that have revolutionized human lives. These are crucial for optical fibre sensor (OFS) interrogation systems. Thus, the characteristics of each source are strongly connected to its sensor system. In large monitoring systems, different OFS are multiplexed in the same optical network. Hence, it exists an increasing necessity of new and special light sources for the new networking requirements. The project aims to develop a revolutionary laser system for high performance remote multiplexing sensor networks for Sustainable Development and Smart Cities applications. The project “ReSOLeS” mainly focus on the research and development of a novel reconfigurable spectrum optical fiber laser source. It is based on the random distributed feedback (RDFB) effect. The modeless characteristic of RDFB lasers allows controlling the emitted frequencies by the internal modulation of the distributed laser cavity, which the applicant first demonstrated. To date, laser spectrum was modified only by filtering the cavity. In this project, we propose an innovative approach that uses a modulating signal to control the output spectrum. This enable higher spectral flexibility and reconfigurability speed than the traditional filtered laser cavities. To make it possible, first, we will develop a model of the system and that will be implemented by software. Next, the system will be experimentally demonstrated and two system enhancements will be tested. Finally, it will be validated in high performance optical fiber sensor networks for Smart Cities applications. This interdisciplinary project will combine the fellow’s expertise in RDFB lasers with the world-leading expertise of the host’s Smart Cities Institute in fiber lasers, OFSs and Smart Cities. In addition, “ReSOLeS” will benefit from the host’s well-established partnerships in academia and industry, and from the training and mentoring opportunities for the fellow's career development.
During the fellow´s incorporation to the research group we developed model based on the Fourier Transform (FT) and a software to control the modulation signal. This software also includes all the instruments’ control protocol. Model results for the modulation signals were validated for two output spectral forms: a multi-wavelength emission and a single wavelength sweep. Next, signals calculated by the model were tested in the optical system. The output spectrum changed as expected but showing lower performance as anticipated in the project proposal. In this way, the modulation of the pump power showed high potential to solve these issues.
Due to the collaboration agreement that UPNA already has with Pamplona´s City Council, tasks related to the technology validation work package -supposed to be at the end of the fellowship- were relocated at the beginning of the fellowship. This was devoted to validate the technology into real applications. Then, in the framework of the collaboration agreement with the City Council, the fellow includes some tasks regarding the installation and validation that enable the future validation of the laser system.
In addition to the project plan, the incorporation of the fellow in the research group lead to synergies and collaborations with other researchers. Due to the previous experience of MB in fibre sensors and lasers, new developments were arisen. Specifically, Mikel participated on the multiplexing strategies to incorporate different sensors in networks and in the development of new and low-cost interrogation systems. Also, he collaborated to develop a distributed interrogation system to measure the moisture-front evolution in soils. Next, as part of a final degree project that the fellow supervised, the under-graduate student, in close supervision of the fellow, developed a simple interrogation system based on the continuous wavelength sweep due to the direct modulation of the current of a laser diode in combination with a temperature change. Finally, he provided support in a research project in collaboration with the company STI Norland S.A. to install FBG sensors and measure the torsion on solar trackers.
Along the full project we generated 10 contributions to the most important conferences in optical fiber sensors international conferences. Besides, it is expected to publish soon a paper in an international high-impact journal such as Optics Express, Optics Letters and Laser Physics Letters (open access version available for all of them). Currently, two papers are in generation progress to be submitted to high-impact journals. Also, this project stimulated an original idea that at the end of the grant is in patent preparation and it shows high potential to be transferred to market through a spin-off company.
Due to the collaboration agreement that UPNA already has with Pamplona´s City Council, tasks related to the technology validation work package -supposed to be at the end of the fellowship- were relocated at the beginning of the fellowship. This was devoted to validate the technology into real applications. Then, in the framework of the collaboration agreement with the City Council, the fellow includes some tasks regarding the installation and validation that enable the future validation of the laser system.
In addition to the project plan, the incorporation of the fellow in the research group lead to synergies and collaborations with other researchers. Due to the previous experience of MB in fibre sensors and lasers, new developments were arisen. Specifically, Mikel participated on the multiplexing strategies to incorporate different sensors in networks and in the development of new and low-cost interrogation systems. Also, he collaborated to develop a distributed interrogation system to measure the moisture-front evolution in soils. Next, as part of a final degree project that the fellow supervised, the under-graduate student, in close supervision of the fellow, developed a simple interrogation system based on the continuous wavelength sweep due to the direct modulation of the current of a laser diode in combination with a temperature change. Finally, he provided support in a research project in collaboration with the company STI Norland S.A. to install FBG sensors and measure the torsion on solar trackers.
Along the full project we generated 10 contributions to the most important conferences in optical fiber sensors international conferences. Besides, it is expected to publish soon a paper in an international high-impact journal such as Optics Express, Optics Letters and Laser Physics Letters (open access version available for all of them). Currently, two papers are in generation progress to be submitted to high-impact journals. Also, this project stimulated an original idea that at the end of the grant is in patent preparation and it shows high potential to be transferred to market through a spin-off company.
In this project we contributed beyond the state of the art with the proposal of a new concept of reconfigurable spectrum photonic sources by internal modulation of RDFB laser cavities. Awaiting to be published, it was preliminary demonstrated the ability of changing the spectrum of modulated lasers sources by controlling the modulating signal.
In the framework of the research group, it has been developed new optical fibre sensors structures based on micro-structured fibres and femto-second drilling. Also, new interrogation systems and distributed techniques have been developed. Previous developments stimulated the invention of a new low-cost interrogation technology for traffic monitoring applications that is now in process of patent preparation. Besides, this invention shows special interest to be transferred to society through a spin-off company. Apart from the impact this technology would have in the new concepts of smart cities contributing in the traffic control, safety, pollution and other benefits to the society.
In the framework of the research group, it has been developed new optical fibre sensors structures based on micro-structured fibres and femto-second drilling. Also, new interrogation systems and distributed techniques have been developed. Previous developments stimulated the invention of a new low-cost interrogation technology for traffic monitoring applications that is now in process of patent preparation. Besides, this invention shows special interest to be transferred to society through a spin-off company. Apart from the impact this technology would have in the new concepts of smart cities contributing in the traffic control, safety, pollution and other benefits to the society.