- 标题
- 摘要
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- 实验方案
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Sub-nanosecond multiple-wavelength harmonic mode-locked Tm-Ho co-doped fiber laser
摘要： We demonstrate an all-fiber sub-nanosecond passively mode-locked Tm-Ho co-doped fiber laser. With 1.1-km single-mode fiber (SMF) inserted into the cavity, the laser system can generate 183.4-kHz and 720-ps pulses based on a GaAs saturable absorber (SA). The output spectrum is presented with three wavelengths, which are at 1858.5, 1861.3, and 1864.2 nm, respectively. In addition, with the adjustment of the polarization controller and pump power, the multiple-pulse operation, such as the harmonic mode-locking operation, can also be observed. Higher order of harmonic mode locking is promising but limited by the damage threshold of the SA.
关键词： Mode-locked lasers,Ultrafast optics,Optical fiber lasers
更新于2025-09-23 15:21:01
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Transmitter and Dispersion Eye Closure Quaternary (TDECQ) and its sensitivity to impairments in PAM4 waveforms
摘要： This paper presents the principles behind the transmitter and dispersion eye closure quaternary (TDECQ) test. A novel method to decompose TDECQ values is proposed where the result is separated into penalties from signal impairments that are either equalizable or non-equalizable by the reference receiver, enabling a more comprehensive study of signal quality. Moreover, the impact of selected impairments is studied in terms of their TDECQ penalty and its composition. This is achieved by producing generic test signals, where isolated impairments are applied to a high quality reference signal. The impairments include low-pass filtering, amplitude noise, compression and eye skew. Low-pass filtering is shown to contribute mainly to increase the equalizable penalty while noise, compression and eye skew are shown to affect mainly the non-equalizable part. The results serve as a generic guideline to understand the engineering rules and parameter limits that are needed to design links using TDECQ.
关键词： Physical Layer,system validation,pulse modulation,signal analysis,Optical fiber communication
更新于2025-09-23 15:21:01
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EDC-Mediated Oligonucleotide Immobilization on a Long Period Grating Optical Biosensor
摘要： We present the development and simplification of label-free fiber optic biosensors based on immobilization of oligonucleotides on dual-peak long period gratings (dLPGs). This improvement is the result of a simplification of biofunctionalization methodology. A one-step 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated reaction has been developed for the straightforward immobilization of unmodified oligonucleotides on the glass fiber surface along the grating region, leading to covalent attachment of a 5′-phosphorylated probe oligonucleotide to the amino-derivatized fiber grating surface. Immobilization is achieved via a 5′phosphate-specific linkage, leaving the remainder of the oligonucleotide accessible for binding reactions. The dLPG has been tested in different external media to demonstrate its inherent ultrahigh sensitivity to the surrounding-medium refractive index (RI) achieving 50-fold improvement in RI sensitivity over the previously-published LPG sensor in media with RI’s relevant to biological assays. After functionalization, the dLPG biosensor was used to monitor the hybridization of complementary oligonucleotides showing a detectable oligonucleotide concentration of 4 nM. The proposed one-step EDC reaction approach can be further extended to develop fiber optic biosensors for disease analysis and medical diagnosis with the advances of label-free, real-time, multiplex, high sensitivity and specificity.
关键词： EDC-mediated reaction,Label-free,DNA,Oligonucleotide,Optical fiber biosensor,Long period grating
更新于2025-09-23 15:21:01
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Plastic fiber evanescent sensor in measurement of turbidity
摘要： The construction and working principles of a plastic fiber sensor for examining the level of turbidity is studied in this paper. This work focuses on designing an inexpensive turbidity sensor that incorporates a pair of multimode fibers (MMF) that are attached side by side and their beveled tips are mounted vertically. The efficiency of different beveled angles is evaluated by simulation with Tracepro software. The reflected signal is collected by immersing the sensor head into a water mixture and analyzed for various concentration. It was found that there is a linear increment of output intensity when concentration of mixture is increased. The turbidity sensor is tested with real samples that are collected from lake, river and coastal areas to demonstrate its consistency with commercial apparatus in natural compounds. The results showed that the proposed sensor structure is able to produce reliable results in a dynamic range of detection from 0 to 1000 Nephelometric Turbidity Unit (NTU) to facilitate practical field measurements.
关键词： Optical fiber sensor,Tracepro software,Water quality monitoring,Turbidity
更新于2025-09-23 15:21:01
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Periodic and N-kink-like optical solitons for a generalized Schr?dinger equation with variable coefficients in an inhomogeneous fiber system
摘要： A generalized Schr?dinger equation in an inhomogeneous optical fiber system is investigated, which is with variable gain coefficient, variable dispersion coefficient and variable nonlinearity coefficient. Analytical soliton solution and its compatible condition are derived by using the auxiliary equation method. Through setting the dispersion function and gain function, the periodic, doubly periodic, and N-kink-like solitons are excited and observed.
关键词： Inhomogeneous optical fiber system,N-kink-like soliton,Periodic soliton,Variable coefficient,Analytical solition solution,Generalized Schr?dinger equation
更新于2025-09-23 15:21:01
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Integration of chiral cellulose nanocrystal films in silica optical fibers
摘要： Cellulose nanocrystals have attracted great attention as new “wonder” materials for photonic applications owing to their unique property of spontaneous self-assembly to form chiral nematic films. Here, the incorporation of chiral cellulose nanocrystal films on a photonic waveguide is demonstrated for the first time – in the form of integrated silica optical fibers with a helicoid nanocrystal film on their input facet. In order to achieve repeatable cholesteric ordering across the fiber core modal area, a fabrication method was developed where several optical fiber facets form part of a larger flat surface, which acts as the substrate for the planar anchoring of the cellulose nanocrystals. The resultant optical fibers exhibit significant circular dichroism (almost 40%) in transmission and act as all-fiber spectral filters. The proposed fabrication technique provides a simple, low-cost method for developing chiral silica optical fibers that remain compatible with standard telecommunication fiber technology. It is envisioned that the incorporation of cellulose nanocrystals in other optical fiber types will enable the development of a new class of fiber devices.
关键词： optical films,optical device fabrication,optical materials,optical polarization,fiber optics,optical fibers,optical fiber devices
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - The Autoconvolution Method Use for Positioning Photonic Crystal Fibers
摘要： In this paper, the autoconvolution method was investigated to determine the position of the longitudinal axis of the photonic crystal fiber and to determine the center of the mode field in the cross section. Knowing the center of the PCF mode field, one can determine the cross section in which the diameter of the mode field will be maximal. This allows a more precise positioning of two identical PCF during connection. The proposed method allows improving the quality of the positioning of the PCF by transverse, angular, longitudinal displacements, and also by the mutual angle of rotation of the connected PCFs.
关键词： optical fibers control,optical power loss,photonic crystal fiber,optical fiber connection,autoconvolution method,mode field,near-field technique
更新于2025-09-23 15:19:57
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Method for increasing the core count and area of high density optical fiber bundles
摘要： Current manufacturing methods limit the increase in both core count and the area for optical fiber bundles. Here a method for increasing the core count and hence the available image area of high density optical fiber bundles, through fusing multiple smaller sized sub-bundles is proposed and experimentally investigated. The key issue being investigated is whether it is possible to eliminate or reduce the dead-space between cylindrical sub-bundles, where no cores are present to spatially sample an image. Small sample lengths of fused optical fiber bundles are fabricated and characterized using an optical and scanning electron microscope to assess the reduction in dead-space and the optical losses near the interfaces. We demonstrate a 30% decrease in the dead-space area through fusing three equally sized sub-bundles in a triangular arrangement, while still retaining the light-guiding ability of more than 70% of the cores which transported into this region. We also assessed the optical losses for cores near the fused interfaces, at different wavelengths in the visible spectrum. A model of the propagation modes supported by the cores is explored which attributes these losses to the increasing eccentricity of cores near the fused interfaces.
关键词： optical fiber imaging,Multicore fiber,linearly polarized modes,fiber fabrication and design
更新于2025-09-23 15:19:57
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Femtosecond laser direct written off-axis fiber Bragg gratings for sensing applications
摘要： First order off-axis fiber Bragg gratings (FBGs) were fabricated in a standard single mode fiber (SMF-28e) through femtosecond laser direct writing. A minimum offset distance between the grating and core center of 2.5 μm was found to create a multimode section, which supports two separate fiber modes (LP0,1 and LP1,1), each split into two degenerate polarization modes. The resulting structure breaks the cylindrical symmetry of the fiber, introducing birefringence (≈10?4) resulting in a polarization dependent Bragg wavelength for each mode. Based on the modal and birefringence behavior, three off-axis FBGs were fabricated with 3.0, 4.5 and 6.0 μm offsets from the core center, and then characterized in strain, temperature, and curvature. The tested off-axis FBGs exhibited a similar strain sensitivity of ~1.14 pm/μ? and a temperature sensitivity of ~12 pm/C. The curvature and orientation angle were simultaneously monitored by analyzing the intensity fluctuation and the wavelength shift of the LP1,1 Bragg resonance. A maximum curvature sensitivity of 0.53 dB/m?1 was obtained for the off-axis FBG with a 3.0 μm offset.
关键词： optical fiber sensors,femtosecond laser direct writing,single mode fiber,off-axis fiber Bragg gratings,Birefringence
更新于2025-09-23 15:19:57
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Optical Fiber Refractometer Based Metal Ion Sensors
摘要： Research into optical fiber refractometers yielded remarkable results over the past decade. Numerous sensing schemes were proposed and demonstrated, which possessed different advantages while facing unique limitations. On top of their obvious applications in measuring refractive index changes of the ambient environment, several studies reported advanced applications of such sensors in heavy metal ion detection by means of surface coating of the refractometers with heavy metal ion sensitive materials. This paper surveys the effort these optical fiber metal ion sensors based on surface coated optical fiber refractometer, discusses different technologies and methods involved, and highlights recent notable advancements.
关键词： optical fiber technology,heavy metal detection,optical fiber sensors,chemical sensing
更新于2025-09-23 15:19:57