98%
921
2 minutes
20
Finding suitable fiber amplifiers is one of the key strategies to increase the transmission capacity of fiber links. Recently, bismuth-doped fiber amplifiers (BDFAs) have attracted much attention due to their distinctive ultra-wideband luminescence properties. In this paper, we propose a linear cavity double pass structure for BDFA operating in the O and E bands. The design creates a linear cavity within the amplifier by combining a fiber Bragg grating (FBG) and a fiber mirror to achieve dual-wavelength pump at 1240 nm and 1310 nm. Meanwhile, the configuration of a circulator and mirror facilitates bidirectional signal propagation through the BDFA, resulting in a double-pass amplification structure. We have tested and analyzed the performance of the linear cavity double pass structure BDFA under different pump schemes and compared it with the conventional structure BDFA. The results show that the gain spectrum of the new structure is shifted toward longer wavelengths, and the gain band is extended from the O band to the O and E bands compared with the conventional structure. In particular, the linear cavity double pass structure BDFA has more relaxed requirements on the stability of the pump and signal power. This work provides a positive reference for the design, application, and development of BDFAs.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1364/OE.525101 | DOI Listing |
Phys Rev Lett
August 2025
CNR-INO, Largo Enrico Fermi 6, I-50125 Firenze, Italy.
We experimentally investigate a system composed of two levitating nanospheres whose motions are indirectly coupled via coherent scattering in a single optical cavity mode. The nanospheres are loaded into a double longitudinal tweezer created with two lasers at different wavelengths, where chromatic aberration leads to the formation of two separate trapping sites. We achieve strong coupling between each pair of modes in the transverse plane of the tweezer, and we show the emergence of dark modes in the overall coupled motion.
View Article and Find Full Text PDFA compact low-level RF (LLRF) control system based on RF system-on-chip (RFSoC) technology has been designed for the Advanced Concept Compact Electron Linear-accelerator (ACCEL) program, which has challenging requirements in both RF performance and size, weight, and power consumption (SWaP). The compact LLRF solution employs the direct RF sampling technique of RFSoC, which samples the RF signals directly without any analog upconversion and downconversion. Compared with the conventional heterodyne based architecture used for the LLRF system of a linear accelerator (LINAC), the elimination of analog mixers can significantly reduce the size and weight of the system, especially with LINAC requiring a larger number of RF channels.
View Article and Find Full Text PDFTalanta
September 2025
College of Chemistry and Chemical Engineering, College of Materials Science and Engineering, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Qingdao Application Technology Innovation Center of Photoelectric Biosensing for Clinical Diagnosis and Treatment, Instrument
Rational optimization of the pore size and topology of porous nanocarriers is crucial for improving the loading amount of luminophore and enhancing electrochemiluminescence (ECL) performance. In this study, an equimolar linear ligand replacement strategy was employed to synthesize novel mesoporous metal-organic frameworks (MOFs) for encapsulating Ru(bpy) (Ru@Zr MOFs) under room temperature without an acid modulator. Ingenious ligand substitution allows precise control of pore size, enabling encapsulation at the single-molecule level within mesoporous cages.
View Article and Find Full Text PDFTalanta
August 2025
Department of Chemistry, Faculty of Natural and Exact Sciences, Universidad de Oriente, Av. Patricio Lumumba, Santiago de Cuba, 90100, Cuba.
Molecularly imprinted polymers (MIPs) have been studied to be used as a platform for electrochemical sensing devices, with special regard to the determination of pesticides. Due to MIP applicability, in the present research, we develop a glassy carbon electrode (GCE) modified with a molecularly imprinted nanocomposite based on the doping of poly(3,4-ethylenedioxythiophene) (PEDOT) with chitosan (Chit) and TiO nanoparticles for sensing atrazine in environmental samples. The construction of the MIP nanocomposite was divided into four parts, which include the chitosan-TiO layer formation by simple drop-casting on the GCE, the doping and electropolymerization of the Chit+TiO+PEDOT layer, cavity formation, and elution.
View Article and Find Full Text PDFEur J Radiol
August 2025
Department of Radiology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China. Electronic address:
The mechanisms underlying the different morphological evolution of recent small subcortical infarcts (RSSIs)-ranging from cavitation to complete disappearance-remain incompletely understood. Free water (FW), derived from diffusion tensor image, has emerged as a sensitive marker reflecting various pathophysiological processes that may influence RSSI evolution. This study aimed to investigate whether baseline FW measures and their longitudinal changes are associated with the morphological evolution of RSSIs.
View Article and Find Full Text PDF