Splicing Point Research Articles

Ultracompact all-fiber self-transceiving ultrasonic probe with an enhanced working distance.

All-optical ultrasonic probes exhibit notable benefits in ultrasonic detection and imaging. Typically, two separate optical fibers are used for excitation and detection, yet limited research has explored the integration of both functionalities within a single fiber. In this Letter, to our knowledge, a new method for fabricating an all-fiber self-transceiving ultrasonic probe is proposed with a lateral dimension of less than 500 µm. Double cladding fiber (DCF) is spliced with a short segment of thin-diameter single-mode fiber (TDSMF), which is then embedded into a fiber bubble to form a Fabry-Perot cavity, and the bubble surface is coated with a composite material layer. The pulsed laser propagates through the inner cladding of DCF and leaks from the splicing point of DCF-TDSMF, inducing the material excitation for efficient ultrasound generation. The core-guided detection laser is directed to the TDSMF end, entering the bubble microcavity and inducing an optical interference for weak echo detection. The emitting functionality produces an ultrasound with a -6 dB bandwidth of 17.5 MHz and a peak frequency of 6.29 MHz, which is well-matched with the fiber microcavity's response frequency of 3.29 MHz. Through self-transceiving experiments, low-noise pulse-echo signals are captured at varying working distances of up to 3.78 cm. The proposed probe exhibits great potential in biomedical and industrial fields due to its all-fiber miniaturization and enhanced-distance detection capability.

Splicing of Helix Framework in Modified Nagata Method Stage I for Auricle Reconstruction in Patients With Insufficient 8th Rib Cartilage.

The 8th rib cartilage was sometimes insufficient to construct a complete external helix in ear reconstruction for microtia. The aim of this study was to investigate the splicing technique of 8th rib cartilage in modified Nagata method stage I. Between September 2022 and May 2023, 231 consecutive patients with microtia underwent auricular reconstruction with modified Nagata method stage I. Thirty-four patients with insufficient 8th rib cartilage were screened out by three-dimensional (3D) computed tomography preoperatively, who were included in the study prospectively. The 8th rib was spliced to create the external helix when fabricating the ear framework in the stage I surgery for the 34 patients. The median duration of follow-up was 12.1 months (8-15 months). There were no perioperative complications in our study. During follow-up, all patients had satisfying outcomes, with no inward collapse, displacement, or absorption of the spliced external helix. The splicing point was not obvious. It was safe and effective to splice the 8th rib cartilage for external helix of the cartilage framework in ear reconstruction for microtia.

Fiber Bragg gratings fabricated in fibers with different geometries by femtosecond laser written through the coating and their applications in strain sensing and fiber laser

Applications of the type-I fiber Bragg gratings (FBGs) written through the coating (TTC) in strain sensing and tunable distributed Bragg reflector (DBR) fiber lasers were demonstrated. We reported the principle of selecting the distance between the fiber and the phase mask when writing type-I TTC FBGs. Type-I TTC FBGs written in commercially available acrylate-coated fibers with various geometries and their strain responses were demonstrated. Results showed that the strain sensitivity of FBGs increases as the core-diameter decreases, probably due to the waveguide effect. In addition, a continuously tunable DBR fiber laser based on TTC FBGs was achieved with a wavelength tuning range of 19.934 nm around 1080 nm, by applying a strain of 0-21265.8 µɛ to the laser resonant cavity. The wavelength tuning range was limited by the splice point between the gain fiber and the passive fiber for transmitting pump and signal lasers. When the pump power was 100 mW, the relative intensity noises were −97.334 dB/Hz at the relaxation oscillation peak of 880 kHz and −128 dB/Hz at frequencies greater than 3 MHz. The results open a potential scheme to design and implement continuously tunable fiber lasers and fiber laser sensors for strain sensing with a higher resolution.

Modified Spatially and Spectrally Resolved Analysis of Mode Coupling Characteristics at the Splicing Point of Few-Mode Fibers

Modified Spatially and Spectrally Resolved Analysis of Mode Coupling Characteristics at the Splicing Point of Few-Mode Fibers

Nonsense mutation suppression is enhanced by targeting different stages of the protein synthesis process.

The introduction of premature termination codons (PTCs), as a result of splicing defects, insertions, deletions, or point mutations (also termed nonsense mutations), lead to numerous genetic diseases, ranging from rare neuro-metabolic disorders to relatively common inheritable cancer syndromes and muscular dystrophies. Over the years, a large number of studies have demonstrated that certain antibiotics and other synthetic molecules can act as PTC suppressors by inducing readthrough of nonsense mutations, thereby restoring the expression of full-length proteins. Unfortunately, most PTC readthrough-inducing agents are toxic, have limited effects, and cannot be used for therapeutic purposes. Thus, further efforts are required to improve the clinical outcome of nonsense mutation suppressors. Here, by focusing on enhancing readthrough of pathogenic nonsense mutations in the adenomatous polyposis coli (APC) tumor suppressor gene, we show that disturbing the protein translation initiation complex, as well as targeting other stages of the protein translation machinery, enhances both antibiotic and non-antibiotic-mediated readthrough of nonsense mutations. These findings strongly increase our understanding of the mechanisms involved in nonsense mutation readthrough and facilitate the development of novel therapeutic targets for nonsense suppression to restore protein expression from a large variety of disease-causing mutated transcripts.

Optimization design of mode-selective ring core photonic lantern based on coupled local mode theory

In this paper, optical field transmission characteristics of a mode-selective ring core photonic lantern (MSRCPL) are theoretically analyzed and its optimization design is also investigated. This MSRCPL is based on a tapered fiber bundle of coreless fiber and glass capillary with low refractive index. Mode evolution characteristics in the taper region and mode coupling characteristics at the splicing point are analyzed. The coupled local mode theory (CLMT) is used to optimize the structure of a 3-port MSRCPL and a 5-port MSRCPL. The impact of taper length, taper shape, taper waist, and geometric arrangement on mode selectivity are calculated. Calculation results indicate that the mode selectivities of the optimized 3-port and 5-port MSRCPL are higher than 23 dB and 18 dB, respectively.

Fabrication of a Counter-Directional Pump/Signal Combiner with Built-In Mode Field Adapter

This article introduces a novel counter-directional pump/signal combiner with a built-in mode field adapter. This combiner offers additional functionality to address the problem of mode field mismatch between the gain fiber and delivery fiber, which occurs when using a large-core (50 μm) signal fiber to suppress stimulated Raman scattering. The combiner exhibits negligible degradation in beam quality as a result of implementing mode field matching and employing an effective feedback alignment technique. The beam quality of the mode field adapter integrated in the combiner is improved by 10%, compared to the conventional approach, thanks to the reduction in splicing points and the prevention of fusion loss caused by tapering-induced cladding diameter mismatch. The combiner demonstrates an average pump coupling efficiency of 98.5% and a temperature rise coefficient of less than 10 °C/kW without active cooling. Furthermore, an integrated device based on the combiner is fabricated to shorten the length of delivery fiber, therefore mitigating the effects of stimulated Raman scattering. All those techniques mentioned above are utilized in a narrow linewidth laser system, resulting in an output of approximately 5840 W with a nearly single-mode characteristic.

Signal processing integrated with fiber-optic Vernier effect for the simultaneous measurement of relative humidity and temperature.

A novel inline Fabry-Perot interferometer (FPI) for simultaneous relative humidity (RH) and temperature monitoring is proposed. The sensing probe consists of a section of hollow core Bragg fiber (HCBF) spliced with a single-mode fiber pigtail. The end-face of the HCBF is coated with Chitosan and ultraviolet optical adhesive (UVOA), forming two polymer layers using a well-designed fabrication process. The surfaces of the layers and splicing point will generate multiple-beam interference and form Vernier-effect (VE) related envelopes in the reflection spectrum. A signal processing (SP) method is proposed to demodulate the VE envelopes from a complicated superimposed raw spectrum. The principle of the SP algorithm is analyzed theoretically and verified experimentally. The sensor's RH and temperature response are studied, exhibiting a high sensitivity of about 0.437 nm/%RH and 0.29 nm/ ∘C, respectively. Using a matrix obtained from experiment results, the simultaneous RH and temperature measurement is achieved. Meanwhile, the simple fabrication process, compact size and potential for higher sensitivity makes our proposed structure integrated with the SP algorithm a promising sensor for practical RH and temperature monitoring.

A method for optimizing the precision of weighted fourier integral transformation algorithm

RCS refers to the radar cross section, which is an important index to reflect the electromagnetic scattering characteristics of the object. RCS measurement is the only method to obtain the real RCS of objects. Since test range often cannot reach the far-field condition for large size object, the near-field-to-far-field transformation(NFFFT) technology is significant in the RCS measurement. The core of NFFFT are different algorithms. Among them, the weighted fourier integral transformation is a universal algorithm, but the data in the aspect angle is segmented in the process, which leads to the discontinuity of the transformation results at the splicing point. This paper introduces a method to optimize the precision of weighted fourier integral transformation algorithm, which can fully suppress the discontinuity of transform results and improve the precision of weighted fourier integral transformation algorithm under the paraxial constraint conditions. Finally, the result of simulation demonstrates the precision and efficiency of this method.

Research on fusion splicing technology of 7-core fiber

The actual trunk multi-core fiber (MCF) splicing is studied by a 7-core fiber for long-distance transmission. The results show that the quality of MCF splicing affects both transmission loss and crosstalk. The splicing quality is influenced by end-face treatment, discharge intensity, discharge time, electrode spacing and other parameters. By aligning the fibers controlled by the axis algorithm and optimization of the fusion splicing parameter, the typical value of splicing point loss can be less than 0.3 dB, which can better meet the requirements of application for engineering wiring.

Efficient 2075-nm laser emission from Ho3+-doped fluorotellurite glass in a compact all-fiber structure.

In this Letter, we report an Ho3+-doped fluorotellurite glass all-fiber laser at 2075 nm. The gain fiber is pumped in-band with a 1976-nm fiber laser and connected by fusion splicing. A high-quality fusion splicing point with a loss of < 0.1 dB was obtained by finely adjusting the splicing power and offset. In addition, by optimizing the writing parameters, a third-order fiber Bragg grating (FBG) with a reflectivity of 98% was achieved at 2075 nm using the femtosecond laser direct-writing method. Using the FBG as the laser cavity mirror and a relatively short 28-cm-long home-made Ho3+-doped fluorotellurite fiber as the laser medium, a laser with a maximum unsaturated output power of 7.33 W was obtained, and the corresponding slope efficiency was as high as 93.4%. The first, to the best of our knowledge, demonstration of the fluorotellurite glass all-fiber ∼2.1-µm laser presented in this work may pave the way for a high-power 2.1-µm fiber laser with a compact structure.

OPGW positioning and early warning method based on a Brillouin distributed optical fiber sensor and machine learning.

A method of optical fiber composite overhead ground wire (OPGW) positioning based on a Brillouin distributed optical fiber sensor and machine learning is proposed. A distributed Brillouin optical time-domain reflectometry (BOTDR) and Brillouin optical time-domain analyzer (BOTDA) are designed, where the ranges of BOTDR and the BOTDA are 110km and 125km, respectively. An unsupervised machine learning method density-based spatial clustering of applications with noise (DBSCAN) is proposed to automatically identify the splicing point based on the Brillouin frequency shift (BFS) difference of adjacent sections. An adaptive parameter selection method based on k-distance is adapted to overcome the parameter sensitivity. The validity of the proposed DBSCAN algorithm is greater than 96%, which is evaluated by three commonly external validation indices with five typical BFS curves. According to the clustering results of different fiber cores and the tower schedule of the OPGW, the connecting towers are distinguished, which is proved as a 100% recognition rate. According to the identification results of different fiber cores of both the OPGW cables and tower schedule, the connecting towers can be distinguished, and the distributed strain information is extracted directly from the BFS to strain. The abnormal region is positioned and warned according to the distributed strain measurements. The method proposed herein significantly improves the efficiency of fault positioning and early warning, which means a higher operational reliability of the OPGW cables.

Deep quantile and deep composite triplet regression

A main difficulty in actuarial claim size modeling is that covariates may have different effects on the body of the conditional distribution and on its tail. To cope with this problem, we introduce a deep composite regression model whose splicing point is given in terms of a quantile of the conditional claim size distribution (rather than a constant). This allows us to simultaneously fit different regression models in the two different parts of the conditional distribution function. To facilitate M-estimation for such models, we introduce and characterize the class of strictly consistent scoring functions for the triplet consisting of a quantile, as well as the lower and upper expected shortfall beyond that quantile. In a second step, this elicitability result is applied to fit deep neural network regression models. We demonstrate the applicability of our approach and its superiority over classical approaches on a real data set from accident insurance.

Technological design of carbon fiber parts with a complex geometric shape for unmanned aerial vehicles

In this paper, the process of technological design of small-sized carbon fiber parts with complex geometry used in the design of unmanned aerial vehicles is considered. Approaches to the placement of splicing points in preform layers are presented. Regularities have been established that relate the number and location of splicing points in the reinforcing layers of carbon fiber reinforced composite and its mechanical characteristics.

Geostationary Full-Spectrum Wide-Swath High-Fidelity Imaging Spectrometer: Optical Design and Prototype Development

The optical system of an imaging spectrometer working on a geostationary earth orbit (GEO) covering a full optical spectrum of 0.3–12.5 μm is analyzed and designed. It enables a ground coverage of 400 × 400 km by internal scanning and achieves a high spatial resolution of 25 m. The full spectrum is divided into five sub-bands, and each band adopts four spectrometers to splice in the field of view to achieve the ultra-long slit required by the wide swath. The total length of the slit is up to 241.3 mm. This paper focuses on compact spectrometers with long slits that can meet the splicing requirements and points out that low spectral distortions, low stray light, high signal-to-noise ratio, and uniform spectral response are necessary for high-fidelity performance. The Offner and Wynne–Offner high-fidelity spectrometers based on convex blazed gratings are designed, and prototypes of each band are developed as well. The properties of long slits and convex blazed gratings are presented. The maximum length of a single slit is 61.44 mm. The groove density of gratings for five bands ranges from 8.8 lp/mm to 312.1 lp/mm, and the peak efficiency is up to 86.4%. The alignment and test of the spectrometers are introduced. Results show that the developed spectrometers have high fidelity and fulfill all requirements.

Ultrahigh Fiber Count and High-Density Cables, Deployments, and Systems

Since the 1980s, the single-core optical fiber cable has been the essential data transmission wiring media, with ongoing increases in deployments. Its use case has broadened, with transmission distances ranging from meters to 10000s km, including intrabuilding, fiber-to-the-home (FTTH), terrestrial, and even submarine trunk lines. Currently, optical fiber cable deployment is strongly driven by cloud-based storage, X as a Service (XaaS), and worldwide data center (DC) functionality with the optical interconnection of massive servers on DC campuses. Hence, it is quite natural that the optical fiber cable industry has developed ultrahigh fiber count, high density, and small diameter optical fiber cable, e.g., 6912-fiber-count cable. With high-density cables, massive data capacity can be installed at one time while saving limited space in an underground duct. High-density cable designs have been developed not just by cable structure optimization but through the process of bundling fibers and the use of high-grade optical fibers. Moreover, many enabling technologies have been developed to support the deployment of ultrahigh fiber count cables, such as fiber identification, connectors, mass fusion splicing, and storage systems for fusion splicing points. In this article, state-of-the-art technologies and prospects for ultrahigh-count and ultrahigh-density optical fiber cables and enabling technologies are explained.

Fabry-Perot interferometers for highly-sensitive multi-point relative humidity sensing based on Vernier effect and digital signal processing.

A highly sensitive relative humidity (RH) sensor based on Fabry-Perot interferometers (FPI) is proposed and experimentally demonstrated. The sensor is fabricated by splicing a segment of hollow core Bragg fiber (HCBF) with single mode fiber (SMF) and functionalized with chitosan and ultraviolet optical adhesive (UVOA) composite at the end of HCBF to form a hygroscopic polymer film. The reflection beams from the splicing point and the two surfaces of the polymer film generate the Vernier effect in the reflection spectrum, which significantly improves the humidity sensitivity of the sensor. To demodulate the envelope based on the Vernier effect and realize multi-point sensing, a digital signal processing (DSP) algorithm is proposed to process the reflection spectrum. The performance of the DSP algorithm is theoretically analyzed and experimentally verified. The proposed sensor demonstrates a high sensitivity of 1.45 nm/% RH for RH ranging from 45% RH to 90% RH. The compact size, high sensitivity and multiplexing capability make this sensor a promising candidate for RH monitoring. Furthermore, the proposed DSP can potentially be applied to other sensors based on the Vernier effect to analyze and extract valuable information from the interference spectrum.

Fault detection sensitivity analysis and optimization of the few-mode fiber link under a dynamic spatial mode crosstalk cumulative effect.

Due to the cumulative effect of dynamic spatial mode crosstalk, it is difficult to obtain the amplitude distribution of backscattering with high purity. Hence, the fault detection sensitivity (FDS) of the few-mode fiber (FMF) link is deteriorated, and the fault location accuracy is limited. This work investigates the characteristics and optimization method of FDS for the FMF link under the dynamic spatial mode crosstalk cumulative effect. We establish a mathematical model and analyze the influence of dynamic spatial mode crosstalk on the FDS of LP01, LP11a, and LP11b modes. The crosstalk mentioned above is caused by different splice misalignments and rotation angles during FMF fusion splicing. The results show that the dynamic spatial mode crosstalk has a great influence on the detection sensitivity of the high-order spatial mode. To solve this problem, the FDS optimization method is proposed based on high-order mode waveform reconstruction. The coupling efficiency matrix at the fusion splice point is estimated by the Rayleigh backscattering waveform of each mode, and the Rayleigh backscattering waveform of high-order spatial modes is reconstructed. The simulation experiment is carried out based on the above theoretical model. The results show that the proposed method can effectively eliminate the influence of the cascading dynamic crosstalk accumulation on the fault loss of the high-order spatial mode, and then optimize the FDS of the FMF link. This study offers new opportunities to develop FMF fault detection devices with high detection sensitivity performance.

Fractal analysis of pore structures in transitional shale gas reservoirs in the Linxing area, Ordos Basin

Studying complex pore structures and fractal characteristics of gas shale provides significant guidance for clarifying the mechanism of shale gas accumulation and realizing its efficient development. In this paper, 12 samples of Taiyuan Formation shale are used as the research object, and the fractal theory is combined with mercury intrusion porosimetry and N2 adsorption technology to innovatively solve the problem of splicing point selection, which can reveal the full-scale pore size distribution of shale. The results demonstrate that the most common types of pores in the chosen samples are pores between or within clay minerals, micropores and mesopores inside organic matter, and microfractures, based on scanning electron microscopy imagery analyses. The pores of shale samples have fractal geometries. The fractal dimension DM1 values in the mercury intrusion porosimetry experiments range from 2.3060 to 2.6528. Two fractal dimensions, DN1 and DN2, may be obtained using the Frenkel-Halsey-Hill fractal method. DN1 values vary from 2.4780 to 2.6387, whereas DN2 values range from 2.5239 to 2.7388. Most macropores in shale samples have a size range of about 0.2 mm, with a wide pore size distribution, and the largest peak of the micro-mesopore volume is generally about 50 nm. The fractal dimension correlates positively with the corresponding pore volume, although the correlation between volume and composition is weak. The relatively strong correlation between fractals and the basic compositions of shale proves the fractal theory’s relevance in defining pore inhomogeneity. This study would contribute to the development of a fractal perspective-based method for pore splicing while also expanding our understanding of pore morphology and structure in transitional shale.

Modeling and analysis of the fusion strength of single-mode optical fiber in the high altitude environment

Up to date, there has been no complete theoretical research and no field experimental reports on the fiber fusion strength in high altitude environments. Therefore, we have conducted an exploratory study on the fiber fusion strength at high altitudes, and firstly analyzed the crack growth characteristics of splicing points, and then considered the influence of fusion variables and parameters on fusion strength. A mathematical model to improve the fiber fusion strength in high altitude environment is established by pondering over the joint effect of temperature, humidity, oxygen content, atmospheric pressure, high wind and gravity. Furthermore, we have implemented multiple field fusion experiments in different altitude areas (53, 2980, 4000, 4200, 4300, 5020 and 5200m). The simulation results are basically consistent with the theoretical analysis. Ultimately, the method proposed has been directly used in the splicing projects at high altitudes, achieving good results.