This study presents the design of an erbium-doped fiber laser(EDFL) featuring switchable wavelength intervals achieved through the implementation of cascaded and parallel Lyot filters. The proposed laser system utiliz...This study presents the design of an erbium-doped fiber laser(EDFL) featuring switchable wavelength intervals achieved through the implementation of cascaded and parallel Lyot filters. The proposed laser system utilizes a cascaded and parallel configuration of three Lyot filters, facilitated by a polarization beam splitter(PBS) for branch switching. The transmission properties of the filter are analyzed through theoretical modeling and experimental validation using the transmission matrix method. The experimental results are found to be consistent with the theoretical predictions, demonstrating the effectiveness of the proposed design. By adjusting the polarization controllers(PCs), the proposed laser can switch between wavelength spacings of 0.46 nm, 0.27 nm, and 0.76 nm, with a maximum optical signal-to-noise ratio(OSNR) of 38 d B. However, the stability of the laser with a 0.27 nm spacing is not high due to wavelength competition. Power fluctuation for 0.46 nm and 0.76 nm intervals is less than 0.93 d B and 0.78 d B in 1 h, with wavelength fluctuation less than 0.068 nm and 0.19 nm, respectively. This EDFL has the advantages of simple structure, great flexibility, and switchability, which can be applied to fiber optic sensing, wavelength division multiplexing(WDM) networks, and other fields that require a very flexible light source.展开更多
A modular DC/DC conversion system with distributed MPPT and centralized step-up converter for photovoltaic energy integrated into HVDC grids is proposed in this paper.The conversion system consists of two power stages...A modular DC/DC conversion system with distributed MPPT and centralized step-up converter for photovoltaic energy integrated into HVDC grids is proposed in this paper.The conversion system consists of two power stages,with MPPT converter as the first stage and a step-up converter as the second stage.Both stages are modular structures.For the distributed MPPT stage,interleaved boost topology is utilized to effectively reduce the input and output ripples without adding extra components.For the centralized step-up stage,narrow-switching-frequency-variation LLC topology is employed,with the modules being configured as input-parallel-output-series structure.Full-range soft-switching property is achieved in the LLC stage to minimize switching losses.Theoretical analysis is carried out for the system voltage gain and design principles.Simulation and experimental results of a 3kW prototype system are presented to verify the theoretical analysis of the proposed system.展开更多
基金supported by the Primary Research and Development Plan of Zhejiang Province (No.2023C03014)the Key Research and Development Program of Zhejiang Province (No.2022C03037)。
文摘This study presents the design of an erbium-doped fiber laser(EDFL) featuring switchable wavelength intervals achieved through the implementation of cascaded and parallel Lyot filters. The proposed laser system utilizes a cascaded and parallel configuration of three Lyot filters, facilitated by a polarization beam splitter(PBS) for branch switching. The transmission properties of the filter are analyzed through theoretical modeling and experimental validation using the transmission matrix method. The experimental results are found to be consistent with the theoretical predictions, demonstrating the effectiveness of the proposed design. By adjusting the polarization controllers(PCs), the proposed laser can switch between wavelength spacings of 0.46 nm, 0.27 nm, and 0.76 nm, with a maximum optical signal-to-noise ratio(OSNR) of 38 d B. However, the stability of the laser with a 0.27 nm spacing is not high due to wavelength competition. Power fluctuation for 0.46 nm and 0.76 nm intervals is less than 0.93 d B and 0.78 d B in 1 h, with wavelength fluctuation less than 0.068 nm and 0.19 nm, respectively. This EDFL has the advantages of simple structure, great flexibility, and switchability, which can be applied to fiber optic sensing, wavelength division multiplexing(WDM) networks, and other fields that require a very flexible light source.
基金Supported by the National Key Research and Development Program“Novel DC-DC Boost Converter Module Based on Wide Bandgap Power Device for HVDC-Connected Photovoltaic Unit”(2016YFB0900205).
文摘A modular DC/DC conversion system with distributed MPPT and centralized step-up converter for photovoltaic energy integrated into HVDC grids is proposed in this paper.The conversion system consists of two power stages,with MPPT converter as the first stage and a step-up converter as the second stage.Both stages are modular structures.For the distributed MPPT stage,interleaved boost topology is utilized to effectively reduce the input and output ripples without adding extra components.For the centralized step-up stage,narrow-switching-frequency-variation LLC topology is employed,with the modules being configured as input-parallel-output-series structure.Full-range soft-switching property is achieved in the LLC stage to minimize switching losses.Theoretical analysis is carried out for the system voltage gain and design principles.Simulation and experimental results of a 3kW prototype system are presented to verify the theoretical analysis of the proposed system.
