Libo Yuan

Guilin University of Electronic Technology · School of Opto-electronic Engineering

Optical tweezers have been widely used for optical trapping and manipulating particles at the microscopic scale with a tightly focused laser beam. Over the recent years, optical fiber tweezers have attracted extensive attention due to their simple fabrication process, compact structure, strong anti-interference ability, convenient utilization, comp...

We propose and demonstrate a high sensitivity curvature sensor based on the cascaded structure of single mode fiber-graded index multimode fiber-hollow core fiber-single mode fiber, and study the influence of the incident light angle on the sensitivity of anti-resonance curvature sensor. The angle of light entering the hollow core fiber can be modu...

A high-purity and super-stable vortex beam generator with a large mode field diameter based on chiral fiber gratings is proposed and fabricated. The double-clad fiber (DCF) is twisted with arc-discharge heating, and its core mode is completely converted to the inner cladding OAM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http:...

In this paper, we propose and investigate a refractive index (RI) sensor with sectional sensitivity based on cladding-regenerated long period fiber grating (CR-LPFG). The CR-LPFG is fabricated by using CO2 laser to polish on the composite structure of single-mode fibers(SMFs) spliced with multi-mode fibers(MMFs). The operating mechanism of the CO2...

This paper presents a circular Airy beam generator based on a fiber end integrated surface plasma lens. The surface plasma lens consists of a nano-annular slot and an array of series concentric circular grooves etched on the gold film coated on the fiber end. When the fiber light field illuminates the nano-annular slot, surface plasmon polaritons (...

This article proposes and demonstrates an optical fiber vector magnetic field sensor based on magnetofluid-encapsulated polarization-maintaining fiber (PMF) single-end offset fusion spliced hollow-core fiber (HCF) structure. Thanks to the unique fast and slow axes structure of the PMF, when the two axes are offset fused with HCF, respectively, the...

In this article, we propose and demonstrate a probe-type multi-core fiber (MCF) sensor for the multi-parameter measurement of seawater. The sensor comprises an MCF and two capillary optical fibers (COFs) with distinct inner diameters, in which a 45° symmetric core reflection (SCR) structure and a step-like inner diameter capillary (SIDC) structure...

An all-optical fiber magnetic field and temperature simultaneous measurement sensor based on single mode fiber (SMF)-multimode fiber (MMF)-SMF-hollow core fiber (HCF)-SMF structure is proposed. The sensing structure is sealed with a capillary tube infiltrated with magnetic fluid. By varying the external magnetic field and temperature, the transmiss...

A cascaded side-polish plastic optical fiber (POF) and FONTEX optical fiber based surface plasmon resonance (SPR) sensor is proposed for simultaneous measurement of refractive index (RI) and temperature. The side-polish POF and FONTEX optical fiber are connected by using the UV glue in a Teflon plastic tube. The SPR phenomenon can be excited at bot...

A vectorial distributed vibration sensing approach based on two-beam $\phi$ -OTDR and four-core fiber is investigated. The theoretical derivation shows that the vibration direction angle can be calculated from the arctangent of the ratio of the phase difference between two sets of orthogonal diagonal fiber core pairs in an untwisted homogeneous f...

Compared to single-parameter and dual-parameter sensors, the design of multi-parameter sensors is generally more complex. As a result, finding ways to enhance sensor integration, eliminate cross-sensitivity between channels, and reduce the difficulty of demodulation has always been a challenging issue. In this research, we propose and demonstrate a...

A high sensitivity optical fiber temperature sensor based on a liquid-filled tapered hollow suspended dual-core fiber (HSDCF) is proposed and experimentally demonstrated. The liquid-filled tapered HSDCF constitute a directional coupler. Due to the small distance between cores and the liquid filled in the air hole, resonance coupling occurs between...

In this paper, a frequency-scanned Φ-OTDR based on a frequency shifting loop (FSL) is proposed. The FSL is a fiber optic loop containing an acousto-optic frequency shifter (AOFS) and a fiber optic amplifier that converts a single-frequency pulse into a train of pulses with a fixed time and frequency spacing. By introducing bias light and precise sw...

We report the measurement of the reflection spectrum of a Fabry-Perot interferometer during the diffusion of dopants in optical fiber caused by high-temperature heating, thus indirectly and accurately obtaining the diffusion coefficient of the dopants. The diffusion coefficient of the dopant is measured through the wavelength shift of the interfero...

We proposed a high sensitivity vector accelerometer. The sensor is a cantilever structure composed of long-period fiber grating (LPFG) and fiber Bragg grating (FBG) in cascade. Its unique structure makes the wavelength drift of the LPFG caused by micro-vibration converted into the reflected light intensity of the FBG, and it is not affected by temp...

Field-controlled micro-manipulation represents a pivotal technique in handling microparticles, yet conventional methods often risk physical damage to the targets. Here, we have discovered a completely new mechanism for truly non-contact manipulation through photothermal effect, called thermal-optical tweezers. we employing a laser-engraved photothe...

In the context of optical fiber humidity sensing, the long-term stability of sensors in high humidity and dew environments such as bathrooms or marine climates remains a challenge, especially since many humidity sensitive materials are water soluble. In this study, we use methyldiethanolamine, pentaerythritol triacrylate and Eosin Y to form a liqui...

In this paper, a surface plasmon resonance (SPR) sensor based on a stepped side-polished plastic optical fiber (POF) is proposed and demonstrated for simultaneous measurement of refractive index (RI) and temperature. A differentiated Au-film thickness was deposited on the stepped polished region, which can enlarge the wavelength space for the SPR p...

A challenge in all-fiber-integrated metasurface devices is to efficiently control dispersion in the limited fiber end area to build metasurfaces, therefore, the design of metasurfaces with a special structure becomes crucial to meet the demands of dispersion control. A unique phase response of circularly polarized light in catenary metasurfaces can...

A temperature sensor based on a side-polished two-core fiber (SPTCF) Michelson interferometer (MI) was demonstrated. The temperature sensor is composed of a standard single-mode fiber (SmF), a segment of tapered TCF, and SPTCF coated with polydimethylsiloxane (PDMS). When the temperature changes, the effective refractive index (RI) of the polished...

This paper presents a novel fiber liquid pressure sensor that uses photopolymer glue to generate Fabry-Perot (F-P) interference, resulting in high sensitivity (5.70 nm/kPa) and wide measurement range (0−500 kPa).

A hole-assisted three-core fiber (HATCF) has been proposed as a sensor for simultaneous measurement of refractive index (RI) and temperature. An 8 mm long HATCF is fused between two single mode fibers (SMFs). One air hole of the HATCF is opened by femtosecond laser ablation technique to expose a suspended core to the external environment. Due to th...

An optical fiber sensor for the simultaneous measurement of microdisplacement and temperature based on balloon-shaped single-mode fibers cascaded with a fiber Bragg grating with two core-offset joints is proposed. The interference between the core mode and cladding mode is caused by the stimulation of the cladding mode by the core-offset joints’ st...

In this paper, a torsion sensor with tunable sensitivity based on long period fiber grating (LPFG) written in polarization maintaining fiber (pMf) is proposed. The LPFG is fabricated by polishing periodic complementary grooves on the principal axis of stress of PMf. By modulating with the CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns...

High-precision axial strain sensors are extensively needed in various fields of strain measurement. In this article, a novel optical fiber strain sensor with high sensitivity is designed and experimentally testified. By introducing arched core into the single-mode fiber (SMF) with multimode–single-mode–multimode (MSM) structure, higher order claddi...

In this Letter, we present a high-strain resolution fiber laser-based sensor (FLS) by a novel optical phase-locked loop (OPLL) interrogation technique based on a root mean square detector (RMSD). The sensor consists of a distributed feedback (DFB) fiber laser as a master laser for strain sensing and a fiber Fabry–Perot interferometer (FFPI) as a re...

The deep application of chiral metasurfaces requires higher flexibility. Herein, we propose a multidimensional tunable chiral graphene metasurface, which uses coherent control to obtain more than 0.8 circular conversion dichroism (CCD) at 2.4 THz as a transmission structure. Its operating frequency can be changed in the 1.3–2.4 THz range, while the...

We propose and experimentally demonstrate a balloon-like optical fiber sensor with an anti-resonance mechanism for the simultaneous measurement of displacement and temperature. The sensor consists of a hollow-core fiber spliced between two single-mode fibers and bent into a balloon-like shape. The balloon-like structure not only increases the contr...

Electro-optic modulators are essential devices on silicon photonic chips in modern optical communication networks. This paper presents a compact, low-loss electro-optic modulator. The modulation efficiency is greatly improved by embedding the lower half of the slot waveguide into the buried oxide layer and inserting graphene at the junction. The in...

We demonstrate a method to fabricate an in-fiber integrated multi-waveguide fiber coupler based on thermal diffusion technology to achieve stable and efficient coupling of a single-mode fiber to a multi-waveguide fiber. Simulation results show that the efficient coupling of a single-mode fiber and a multi-waveguide fiber can be realized by introduc...

A composite interferometric all-fiber sensor based on an asymmetric misaligned tapered multimode (ASTM) fiber configuration has been designed and investigated. This optical fiber sensor combines the asymmetric staggered taper (AST) structure, single-mode multimode single-mode (SMS) optical fiber and optical fiber bitaper (OFB) structure during prep...

In this article, we propose a Mach–Zehnder interferometer (MZI) based on cascaded double-assembled long-period fiber gratings (LPFGs) and a waist fiber structure. The refractive index (RI) sensing characteristics of the sensor are investigated both theoretically and experimentally. First, two separate LPFGs are fabricated using a precision fiber cu...

An optical fiber sensor based on a hole-assisted dual-core fiber (HADCF) has been proposed and experimentally demonstrated for dual-parameter measurements. The dual-mode interferometer created uses the LP01 mode and LP11 mode in the suspended core of a specialist optical fiber, combined with a directional coupler formed by using the suspended core...

A hot trend in the development of optoelectronic devices is how to use the principle of surface plasmon resonance to enhance the performance of integrated photonics devices and achieve miniaturization. This paper proposes an accompanying waveguide coupling structure of micro/nano fibers, which consists of two parallel-placed micro/nano fibers (MNFs...

This paper introduces a surface plasmon resonance (SPR) sensor using tapered silica fiber and photopolymer coating for enhanced refractive index (RI) detection. Tapering the silica fiber to a diameter of 10 µm ensures the evanescent wave leaks into a 1.8-µm thick photopolymer film, which increases the average waveguide RI and broadens the RI detect...

This Letter proposes a method that balances miniaturization and high performance of fiber optic speckle spectrometers. The periodically tapered coreless fiber is used as the scattering element to excite more higher-order modes in the coreless fiber. As a result, a remarkable spectral resolution of 0.03 nm in the near-infrared spectrum can be achiev...

This paper presents a novel fabrication method for single-fiber optical tweezers (OTs) with a lens-like tip using a single-mode fiber and dual-photopolymerization that eliminates the need for unique curing light fields and involves no fiber micromachining process. Quantitative analysis of axial and transverse trapping forces applied to transparent...

In this paper, a nested micro-ring refractive index sensor based on a subwavelength grating waveguide and the Vernier effect is proposed. In this scheme, the nested micro-ring structure is combined with a subwavelength grating structure to enhance the contact area between the optical field and the analyte, and the wavelength offset is doubled throu...

PCTF (pear-shaped conjoined-tube fiber) is presented as a new ultraviolet (UV) guiding fiber with low loss. Results indicate that two PCTFs have better properties than that of previous studies in the UV band. The total loss of two PCTFs is less than 1 dB/km, and its bandwidth exceeds 150 nm between 0.2 and 0.4 μm. Furthermore, PCTF's single-mode pe...

In this paper, a reflective surface plasmon resonance (SPR) sensor based on multimode fiber (MMF)-hollow core fiber (HCF) structure is proposed for simultaneous measurement of temperature and humidity. Along the HCF, two different films, i.e., polyvinyl alcohol (PVA) film and polydimethylsiloxane (PDMS) film are coated on the outer surface to gener...

A vector bending sensor based on hole-assisted three-core fiber (HATCF) Mach-Zehnder interferometer (MZI) is demonstrated. The sensor is composed of multi-mode fiber (MMF) - HATCF - MMF structure embedded between two single-mode fibers (SMFs). The bending curvature and direction can be identified by interrogating the wavelength of the interference...

This paper presents a novel fiber liquid-pressure sensor that uses photopolymer glue to generate Fabry–Perot (F-P) interference, resulting in high sensitivity and a wide measurement range. The sensor comprises a single-mode fiber and photopolymer glue; the latter adheres to the fiber’s end face and is decomposed by a 405-nm laser to create an air c...

A dual-parameter optical fiber sensor based on a hole-assisted dual-core fiber (HADCF) has been proposed and experimentally demonstrated. The dual-mode interferometer generated by the LP01 mode and LP11 mode in the suspended core is combined with the directional coupler formed by the suspended core and the center core in a 16 mm long HADCF. Simulta...

A dual-parameter optical fiber sensor based on a hole-assisted dual-core fiber (HADCF) has been proposed and experimentally demonstrated. The dual-mode interferometer generated by the LP01 mode and LP11 mode in the suspended core is combined with the directional coupler formed by the suspended core and the center core in a 16 mm long HADCF. Simulta...

Aiming at the problems of narrow working bandwidth, low efficiency, and complex structure of existing terahertz chiral absorption, we propose a chiral metamirror composed of C-shaped metal split ring and L-shaped vanadium dioxide (VO2). This chiral metamirror is composed of three layers of structure, a gold substrate at the bottom, the first polyet...

The control of information is a defining feature of the information age, and the optical modulator likewise has a crucial role in optical networks. The transmission, processing, and storage of data have demanded low energy consumption and high speed for photonic systems, promoting the development of electro-optic modulators to all-optical modulator...

The realization of a miniaturized spectrometer with high resolution is highly desired but is still a big challenge. Although all-fiber spectrometers based on speckle detection show their great potential for high resolution ones, their long fiber lengths set the greatest obstacle for the miniaturized design. Here, we demonstrate a compact all-fiber...

Micromotors based on fiber optical tweezers (OTs) hold exciting prospects for studying rotary motor proteins, observing the microscopic properties of fluids, and diagnosing diseases. In this paper, we report an all-fiber, OTs-based, rate-controllable, rotary micromotor using laser-induced thermal convection. The optical trapping force can stably tr...

With the development of photonic integration technology, meta-waveguides have become a new research hotspot. They have broken through the theoretical diffraction limit by virtue of the strong electromagnetic manipulation ability of the metasurface and the strong electromagnetic field limitation and guidance ability of the waveguide. However, the re...

In this paper, a temperature sensor based on a point-coated long-period fiber grating (PC-LPFG) is proposed and investigated. This structure is fabricated using a thermal filling method. The point-coating approach effectively increases the coupling efficiency between the sensing unit and the surrounding medium. The polymethyl methacrylate (PMMA), w...

With the development of optical engineering technologies, traditional experimental courses that merely demonstrate theoretical phenomena can no longer meet the demands of optical engineers’ education. In this paper, we propose an experimental course “Fiber-Michelson white light interference experiment” towards the cultivation of optical engineering...

A compact Omega shaped long-period fiber grating (OS-LPFG) for vector bending measurement is proposed and investigated in this paper. This sensor is fabricated by periodically splicing single-mode fiber (SMF) and multi-mode fiber (MMF) into Omega shape to get the purpose of sensitivity enhancing. The proposed OS-LPFG can distinguish the bending dir...

A bending sensor is proposed to demodulate the multi-channel bending signals of multi-core fiber (MCF) to single-channel signals by using the phase mask method combined with the thermal diffusion technology (TDT). A four-core fiber (FCF) bending sensor was fabricated. Each fiber core of the FCF had different resonant wavelengths through the method...

A vector bending fiber sensor based on core-by-core inscribed fiber Bragg gratings in a twin-core fiber has been proposed and experimentally demonstrated. An in-fiber integrated vector bending sensor is realized by using the thermal diffusion technique to fabricate the coupler. The characteristics of the coupler fabricated by thermal diffusion are...

Circular dichroism has promising applications in biology, molecular chemistry, and other fields. The key to obtaining strong circular dichroism is to introduce symmetry breaking into the structure, which leads to a great difference in the response to different circularly polarized waves. Here, we propose a metasurface structure based on three circu...

Based on our current research on long-period fiber gratings (LPFGs), we propose a novel fiber-based sensor for simultaneous measurement of torsion and temperature. The proposed sensor cleverly combines CO2 laser polishing with pre-twist that can introduce elliptical birefringence in the fiber to improve sensing performance. Through comparative meas...

Investigating the thermal decomposition characteristics and mechanisms of nano- and submicron-aluminized 1,3,5-trinitro-1,3,5-triazine (RDX) is essential to optimize the formulations and improve combustion/detonation efficiencies. However, no research has focused on the microscopic scale of a single aluminized RDX particle. We demonstrate an all-fi...

A simple plastic optical fiber (POF) based surface plasmon resonance (SPR) sensor is proposed and demonstrated for simultaneous measurement of refractive index (RI) and temperature. The sensor consists of a series of V-grooves along the POF and a side-polish structure at the other side of the fiber. The V-groove structure can alter the SPR excitati...

A gas pressure sensor composed of cascaded Fabry-Perot interferometers (FPIs) based on Vernier effect was demonstrated. Two hollow silica tubes (HSTs) with different inner diameters were used to construct the FP cavities, and spliced with single-mode fiber (SMF) to make a gas pressure sensor with a closed cavity FPI and an open cavity FPI in series...

Nowadays, optical fiber sensors are extensively being explored for the detection of magnetic fields. Against this backdrop, a highly sensitive magnetic field sensor based on the combination of magnetostrictive material and Vernier effect is proposed and experimentally demonstrated. The proposed sensor consists of two Fabry-Perot interferometers (FP...