We show that long-period fiber grating (LPG) incorporating N-1pi-phase shifts can serve as an Nth order temporal differentiator that operates in transmission. Due to the inherent large bandwidth provided by LPGs, subpicosecond (terahertz-bandwidth) optical signals may be processed with centimeters-length devices. Design parameters for up to fifth-order differentiators are given.
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http://dx.doi.org/10.1364/ol.32.002978 | DOI Listing |
A polarization-independent dual-peak narrow-band filter is proposed and demonstrated theoretically and experimentally, which is realized by using a helical long-period fiber grating (HLPG) but with a period small down to tens of micrometers. Unlike those excessively tilted fiber gratings (Ex-TFGs) or the conventional long-period fiber gratings (LPGs) but with a small period down to tens of micrometers where the generated dual-peak pairs (DPPs) are all of the strong polarization-dependence, the DPPs obtained in this study are of the polarization-independent, which is the first time, to the best of our knowledge, that the underlying mechanism for generation of the polarization-independent DPPs in transmission spectrum of the helical small-period fiber grating (HSPFG) has been revealed both theoretically and experimentally.
View Article and Find Full Text PDFWe propose and demonstrate an ultra-wide tunable mode-locked all-fiber laser based on nonlinear amplifying loop mirror (NALM) with the output of cylindrical vector beams (CVBs). The tuning range covers from 1029 nm to 1098 nm through the intracavity nonlinear polarization evolution (NPE) filter effect. The switchable CVBs between radially and azimuthally polarized beams with mode purity above 90% are generated by incorporating a broadband few-mode long-period fiber grating (LPFG).
View Article and Find Full Text PDFIn this paper, poly(diallyldimethylammonium chloride)(PDDA)/poly(sodium styrene sulfonate)(PSS) nanomembranes were deposited on the surface of long-period fiber gratings (LPFG) using the electrostatic layer-by-layer (LBL) assembly method, and the effect of NaCl on the modulation of LPFG double peaks by PDDA/PSS nanomembranes was investigated. The principle behind the emergence of double peaks was first explored using coupled mode theory, revealing that changes in the mode effective refractive index(RI) occur as the number of nanomembrane layers increases. The experimental results showed that under the conditions of PDDA with NaCl/PSS without NaCl and PDDA without NaCl/PSS with NaCl, double peaks do not appear in the spectra of LPFG as the number of thin film layers increases.
View Article and Find Full Text PDFA high-sensitivity hot-wire anemometer is proposed for use with a cobalt-doped fiber (CDF) based long-period grating (LPG) heated optically by a 1480 nm laser. The CDF-LPG absorbs laser power and generates heat inherently, thereby eliminating the need for both metal coating and mode coupling devices that are usually required in optical fiber grating anemometers. The dip wavelength of the CDF-LPG shifts with airflow velocity due to the cooling effect of the airflow.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Institute for Fiber Engineering and Science (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, Tokida 3-15-1, Ueda, Nagano 386-8567, Japan. Electronic address:
This study presents the first development of Cu (I) acylthiourea complexes (C1-C5) incorporated polycaprolactone/lignin (PCL/Lig) electrospun nanofiber composites (PCL/Lig@Cu(I)). Electrospinning conditions and mass ratios of PCL and lignin were optimized, followed by the incorporation of varying concentrations of Cu(I) complexes. Structural, morphological, and thermal properties were characterized using SEM, TEM, FT-IR, XRD, TGA and WCA analyses.
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