Improving the optoelectronic behavior and stress-deformation stability of conjugated materials is crucial for the realization of their potential applications in flexible optoelectronics.To tune the emission behavior a...Improving the optoelectronic behavior and stress-deformation stability of conjugated materials is crucial for the realization of their potential applications in flexible optoelectronics.To tune the emission behavior and mechanical property of molecular crystals simultaneously via supramolecular salt strategy is rarely reported,which is very important to improve their photophysical behavior and softness for the fabrication of flexible light-emitting device.Herein,supramolecular salt approach has been successfully applied to synthesize two elastic organic fluorescent crystals(CMOH-Py-Cl and CMOH-Py-Br)derived from non-emissive and brittle pyridine-substituted coumarin derivative(CMOH-Py).Their elastic properties can be attributed to the prevalent presence of numerous weak interactions introduced by halogen atoms,which are beneficial to the absorption and release of mechanical energy.Furthermore,density functional theory(DFT)calculations demonstrated a narrowing of the HOMO-LUMO energy gaps from CMOH-Py to CMOH-Py-Cl/CMOH-Py-Br via supramolecular salt approach.Finally,the application of flexible crystal materials in the field of optical waveguides has been investigated.The transformation of crystals in terms of photophysical and mechanical properties,achieved by the supramolecular salt approach,offers novel insights into the design and construction of flexible crystalline materials,providing a new path for the development of next-generation smart materials.展开更多
Integrating the magneto-optical effect into a waveguide-based photonic device becomes more and more interesting.In the work,the planar optical waveguide firstly was prepared in a terbium gallium garnet crystal(TGG)via...Integrating the magneto-optical effect into a waveguide-based photonic device becomes more and more interesting.In the work,the planar optical waveguide firstly was prepared in a terbium gallium garnet crystal(TGG)via the proton implantation with the energy of 4×10^(-1)MeV and the fluence of 6×10^(8)ions/μm^(2).Subsequently,a femtosecond laser with a central wavelength of 800 nm and a power of 3 mW was used to ablate the surface of the planar waveguide,forming the ridge optical waveguide.The dark-mode curve of the planar waveguide was measured by a prism coupling technique.The top-view morphology of the ridge waveguide was observed via a Nikon microscope.The mode field distributions of the planar and ridge waveguides were obtained by an end-face coupling system,and the propagation losses of the two waveguides were measured to be 2.26 dB/cm and 2.58 dB/cm,respectively.The Verdet constants were measured to be-72.7°/T·cm for the TGG substrate and-60.7°/T·cm for the ridge waveguide.The TGG waveguides have a potential in the fabrication of magneto-optical waveguide devices.展开更多
Ferrimagnetic materials exhibiting remanence can be used to achieve unidirectional electromagnetic-field propagation in the form of magnetoplasmons(MPs)in the subwavelength regime.This study investigates the MP proper...Ferrimagnetic materials exhibiting remanence can be used to achieve unidirectional electromagnetic-field propagation in the form of magnetoplasmons(MPs)in the subwavelength regime.This study investigates the MP properties and various guiding modes in a hollow cylindrical waveguide made of materials that exhibit remanence.Pattern analysis and numerical simulations are used to demonstrate that dispersion relationships and electromagnetic-field distribution are strongly affected by the operating frequency and physical dimensions of the structure.In addition,the existence of two different guiding modes is proved,namely regular and surface-wave modes.By adjusting the operating frequency and reducing the diameter of the hollow cylinder,the regular mode can be suppressed so as to only retain the surface-wave mode,which enables unidirectional MP propagation in the cylindrical waveguide.Moreover,the unidirectional surface-wave mode is robust to backscattering due to surface roughness and defects,which makes it very useful for application in field-enhancement devices.展开更多
Optical waveguides in silica-on-silicon are one of the key elements in optical communications.The processes of deep etching silica waveguides using resist and metal masks in RIE plasma are investigated.The etching res...Optical waveguides in silica-on-silicon are one of the key elements in optical communications.The processes of deep etching silica waveguides using resist and metal masks in RIE plasma are investigated.The etching responses,including etching rate and selectivity as functions of variation of parameters,are modeled with a 3D neural network.A novel resist/metal combined mask that can overcome the single-layer masks’ limitations is developed for enhancing the waveguides deep etching and low-loss optical waveguides are fabricated at last.展开更多
We propose and fabricate a vertically integrated thermo-optic waveguide switch. It controls the optical path between two vertically stacked waveguides using the thermo-optic effect of optical polymer. The measured cro...We propose and fabricate a vertically integrated thermo-optic waveguide switch. It controls the optical path between two vertically stacked waveguides using the thermo-optic effect of optical polymer. The measured crosstalk is less than -10 dB.展开更多
Based on attenuated total reflection （ATR） and thermo-optic effect, the polymeric thin film planar optical waveguide is used as the temperature sensor, and the factors influencing the sensitivity of the temperature ...Based on attenuated total reflection （ATR） and thermo-optic effect, the polymeric thin film planar optical waveguide is used as the temperature sensor, and the factors influencing the sensitivity of the temperature sensor are comprehensively analyzed. Combined with theoretical analysis and experimental investigation, the sensitivity of the temperature sensor is related to the thicknesses of the upper cladding layer, the waveguide layer, the optical loss of the polymer material and the guided wave modes. The results show that the slope value about reflectivity and temperature, which stands for the sensitivity of the polymer thin film temperature sensor, is associated with the waveguide film thickness and the guided wave modes, and the slope value is the highest in the zero reflectance of a certain transverse electric （TE） mode. To improve the sensitivity of the temperature sensor, the sensor＇s working incident light exterior angle α should be chosen under a certain TE mode with the reflectivity to be zero. This temperature sensor is characterized by high sensitivity and simple structure and it is easily fabricated.展开更多
Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established base...Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established based on crystalline materials,particularly,are opening exciting possibilities and opportunities in photonic chips by facilitating their on-chip integration with different functionalities and highly compact photonic circuits.Femtosecond-laser-direct writing(FsLDW),as a true three-dimensional(3D)micromachining and microfabrication technology,allows rapid prototyping of on-demand waveguide geometries inside transparent materials via localized material modification.The success of FsLDW lies not only in its unsurpassed aptitude for realizing 3D devices but also in its remarkable material-independence that enables cross-platform solutions.This review emphasizes FsLDW fabrication of waveguide structures with 3D layouts in dielectric crystals.Their functionalities as passive and active photonic devices are also demonstrated and discussed.展开更多
This paper presents the development of a bioinspired multifunctional flexible optical sensor(BioMFOS)as an ultrasensitive tool for force(intensity and location)and orientation sensing.The sensor structure is bioinspir...This paper presents the development of a bioinspired multifunctional flexible optical sensor(BioMFOS)as an ultrasensitive tool for force(intensity and location)and orientation sensing.The sensor structure is bioinspired in orb webs,which are multifunctional devices for prey capturing and vibration transmission.The multifunctional feature of the structure is achieved by using transparent resins that present both mechanical and optical properties for structural integrity and strain/deflection transmission as well as the optical signal transmission properties with core/cladding configuration of a waveguide.In this case,photocurable and polydimethylsiloxane(PDMS)resins are used for the core and cladding,respectively.The optical transmission,tensile tests,and dynamic mechanical analysis are performed in the resins and show the possibility of light transmission at the visible wavelength range in conjunction with high flexibility and a dynamic range up to 150 Hz,suitable for wearable applications.The BioMFOS has small dimensions(around 2 cm)and lightweight(0.8 g),making it suitable for wearable application and clothing integration.Characterization tests are performed in the structure by means of applying forces at different locations of the structure.The results show an ultra-high sensitivity and resolution,where forces in theμN range can be detected and the location of the applied force can also be detected with a sub-millimeter spatial resolution.Then,the BioMFOS is tested on the orientation detection in 3D plane,where a correlation coefficient higher than 0.9 is obtained when compared with a gold-standard inertial measurement unit(IMU).Furthermore,the device also shows its capabilities on the movement analysis and classification in two protocols:finger position detection(with the BioMFOS positioned on the top of the hand)and trunk orientation assessment(with the sensor integrated on the clothing).In both cases,the sensor is able of classifying the movement,especially when analyzed in conjunction with preprocessing and clustering techniques.As another wearable application,the respiratory rate is successfully estimated with the BioMFOS integrated into the clothing.Thus,the proposed multifunctional device opens new avenues for novel bioinspired photonic devices and can be used in many applications of biomedical,biomechanics,and micro/nanotechnology.展开更多
A sensitive optical waveguide（OWG） sensor which can be used to detect volatile organic compounds（VOCs） was presented.The sensing device（element） was fabricated by means of the immobilization of polyvinyl pyrroli...A sensitive optical waveguide（OWG） sensor which can be used to detect volatile organic compounds（VOCs） was presented.The sensing device（element） was fabricated by means of the immobilization of polyvinyl pyrrolidone（PVP）-cyclodextrin（CD） composite film over a single-mode potassium ion exchanged glass OWG via spin-coating method.The sensor shows higher response to styrene gas than to other VOCs and displays a linear response to styrene gas in a range of 1―1000 μL/L.展开更多
Micro-nano-level photonic waveguide regulation is essential for future on-chip photonic integrated systems and is still of great challenges.We report a molecular design strategy,changing the position of the methyl sub...Micro-nano-level photonic waveguide regulation is essential for future on-chip photonic integrated systems and is still of great challenges.We report a molecular design strategy,changing the position of the methyl substituent makes the arrangement of the three isomer molecules different in their respective crystals.Based on this strategy,three sheet-like crystals with different polygonal morphologies were prepared via solution self-assembly approach.The in-depth optical measurements demonstrated that these three microsheet crystals have different 2D optical waveguide performances related to the shapes.Our work provides a feasible design strategy and material preparation method for realizing precise 2D optical waveguide modulation,which lays the foundation for complex photonic integrated systems in the future.展开更多
The alignment coupling between optical waveguide chips and optical fiber arrays is the basis of the alignment coupling of planar optical waveguide devices, and the precise position detection with angle and spacing adj...The alignment coupling between optical waveguide chips and optical fiber arrays is the basis of the alignment coupling of planar optical waveguide devices, and the precise position detection with angle and spacing adjustments is one of the key steps of alignment coupling. A methodology for position detection, and angle and spacing adjustment was proposed for optical waveguide chips and optical fiber arrays based on machine vision. The experimental results show angle detection precision levels higher than 0.05°, line detection precision levels higher than 0.1 μm, and detection time less than 2 s. Therefore, the system developed herein meets the precise requirements necessary for position detection, and angle and spacing adjustments for optical waveguide chips and optical fiber arrays.展开更多
In order to reduce transmission loss of the optical waveguide in Mach-Zehnder (M-Z) electro-optical (EO) polymer modulator,the basic iterative formula of semi-vector finite-difference beam propagation method (FD-BPM) ...In order to reduce transmission loss of the optical waveguide in Mach-Zehnder (M-Z) electro-optical (EO) polymer modulator,the basic iterative formula of semi-vector finite-difference beam propagation method (FD-BPM) is obtained from the scalar wave equation. The transition waveguide is combined with S-type bend branch waveguide for the M-Z EO modulator in the branch waveguide. The effects of structure parameters such as ridge width,length of the branch waveguide and interferometer spacing on the transmission loss are systematically studied by using the semi-vector FD-BPM method. The structure is optimized as an S-sine bend branch waveguide,with rib width w=7μm,length of branch waveguide L=1200μm and interferometer spacing G=22 μm. The results show that the optimized structure can reduce transmission loss to 0.083 dB,which have a certain reference value to the design of optical waveguide in M-Z polymer modulator.展开更多
Calculation shown that the refraction index of Ge_0.6Si_0.4/Sistrained-layer superlattice n≈3.64, when L_w=9 nm and L_b=24 nm. Analgorithm of numerical iteration for effective refraction index isemployed to obtain di...Calculation shown that the refraction index of Ge_0.6Si_0.4/Sistrained-layer superlattice n≈3.64, when L_w=9 nm and L_b=24 nm. Analgorithm of numerical iteration for effective refraction index isemployed to obtain different effective refraction indexes atdifferent thickness (L). As a result, the thickness ofGe_0.6Si_0.4/Si strained-layer superlattice optical waveguide, L≤363nm, can be determined, which is very important for designingwaveguide devices. An optical waveguide can be made into a nanometerdevice by using Ge_0.6 Si_0.4/Si strained-layer superlattice.展开更多
This paper analyzes the characteristic of matching efficiency between the fundamental mode of two kinds of optical waveguides and its Gaussian approximate field.Then, it presents a new method where the mode-field half...This paper analyzes the characteristic of matching efficiency between the fundamental mode of two kinds of optical waveguides and its Gaussian approximate field.Then, it presents a new method where the mode-field half-width of Caussian approximation for the fundamental mode should be defined according to the maximal matching efficiency method. The relationship between the mode-field half-width of the Gaussian approximate field obtained from the maximal matching efficiency and normalized frequency is studied; furthermore, two formulas of mode-field half-widths as a function of normalized frequency are proposed.展开更多
Electron beam lithography(EBL) is a key technology in the fabrication of nanoscale silicon optical waveguide. The influence of exposure dose, the main process parameter of EBL, on the structure profile of poly-methyl ...Electron beam lithography(EBL) is a key technology in the fabrication of nanoscale silicon optical waveguide. The influence of exposure dose, the main process parameter of EBL, on the structure profile of poly-methyl methacrylate(PMMA) after development was studied using a silicon on insulator(SOI) wafer with 220 nm top silicon as the substrate. The relationship between exposure dose and structure pattern width after development was analyzed according to the measurement results. The optimum exposure dose of 220 μC/cm^(2) was found to obtain a final structure consistent with the designed mask value through subsequent processes. At the same time, according to the image segmentation curve tracking technology, the contour extraction process of the dose test results was carried out, and the relationship among mask design value, exposure dose and two-dimensional roughness of boundary contour was analyzed, which can provide reference for the subsequent electron beam lithography of the same substrate material.展开更多
Based on the polynomial interpolation, a new finite difference （FD） method in solving the full-vectorial guidedmodes for step-index optical waveguides is proposed. The discontinuities of the normal components of the...Based on the polynomial interpolation, a new finite difference （FD） method in solving the full-vectorial guidedmodes for step-index optical waveguides is proposed. The discontinuities of the normal components of the electric field across abrupt dielectric interfaces are considered in the absence of the limitations of scalar and semivectorial approximation, and the present PD scheme can be applied to both uniform and non-uniform mesh grids. The modal propagation constants and field distributions for buried rectangular waveguides and optical rib waveguides are presented. The hybrid nature of the vectorial modes is demonstrated and the singular behaviours of the minor field components in the corners are observed. Moreover, solutions are in good agreement with those published early, which tests the validity of the present approach.展开更多
Terbium gallium garnet(Tb_(3)Ga_(5)O_(12),TGG)crystal can be used to fabricate various magneto-optical devices due to its optimal Faraday effect.In this work,400-keV He^(+)ions with a fluence of 6.0×10^(16)ions/c...Terbium gallium garnet(Tb_(3)Ga_(5)O_(12),TGG)crystal can be used to fabricate various magneto-optical devices due to its optimal Faraday effect.In this work,400-keV He^(+)ions with a fluence of 6.0×10^(16)ions/cm^(2)are irradiated into the TGG crystal for the planar waveguide formation.The precise diamond blade dicing with a rotation speed of 2×10^(4)rpm and a cutting velocity of 0.1 mm/s is performed on the He^(+)-implanted TGG planar waveguide for the ridge structure.The darkmode spectrum of the He^(+)-implanted TGG planar waveguide is measured by the prism-coupling method,thereby obtaining the relationship between the reflected light intensity and the effective refractive index.The refractive index profile of the planar waveguide is reconstructed by the reflectivity calculation method.The near-field light intensity distribution of the planar waveguide and the ridge waveguide are recorded by the end-face coupling method.The He^(+)-implanted and diamond blade-diced TGG crystal planar and ridge waveguides are promising candidates for integrated magneto-optical devices.展开更多
We proposed a new saccharides sensor developed by symmetrical optical waveguide(SOW)-based surface plasmon resonance(SPR).This unique MgF_(2)/Au/MgF_(2)/Analyte film structure results in longer suface plasmon wave(SPW...We proposed a new saccharides sensor developed by symmetrical optical waveguide(SOW)-based surface plasmon resonance(SPR).This unique MgF_(2)/Au/MgF_(2)/Analyte film structure results in longer suface plasmon wave(SPW)propagation lengths and depths,leading to an increment of resolution.In this paper,we managed to decorate the dielectric interface(MgF_(2) layer)by depositing a thin polydopamine film as surface adherent that provides a platform for secondary reactions with the probe molecule.3-Aminophenylboronic acid(3-PBA)is chosen to be the saccharides sense probe molecule in the present work.The aqueous huumnor of Diabetes and Cataract patient whose blood glucose level is normal are analyzed and the results dermonstrated that this sensor shows great potential in monitoring the blood siugar and can be adapted in the field of biological monitoring in the future.展开更多
This paper derives the dispersion relation of microring coupled-resonator optical waveguides （CROWs） without any approximation by using the transfer matrix method. Based on the established dispersion relation of CRO...This paper derives the dispersion relation of microring coupled-resonator optical waveguides （CROWs） without any approximation by using the transfer matrix method. Based on the established dispersion relation of CROWs it obtains the slow group velocity and dispersion coefficient. It finds that the effect Of dispersion on optical pulses can be adjusted to balance the effect of nonlinearity by changing coupling coefficient or loss, so optical soliton with group delay can be obtained in microring CROWs. The optical soliton with group delay is of great significance for applications of microring CROWs in delay lines and optical buffers of future all-optical communication systems.展开更多
A series of fluorinated copolyimides containing phthalazinone moieties were prepared from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride(6FDA),3,3'4,4'-benzophenone-tetracarboxylic dianhydride(BPDA)...A series of fluorinated copolyimides containing phthalazinone moieties were prepared from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride(6FDA),3,3'4,4'-benzophenone-tetracarboxylic dianhydride(BPDA)and2-(4-aminophenyl)-4-[4-(4-aminophenoxyl)phenyl]-2,3-phthalazin-1-one(DHPZ-2NH_2)for making polymeric opticalwaveguides.The resulting copolymers containing 0-50 mo1% BPDA/DHPZ-2NH_2 show good solubility and are soluble insome organic polar aprotic solvents.The copolyimides also present excellent thermal stability.These polymers possess highglass transition temperature higher than 603 K and high decomposition temperature above 742 K determined by differentialscanning calorimetry and thennogravimetric analysis,respectively,under a nitrogen atmosphere.Their refractive indicescould be controlled by varying the ratio of 6FDA and BPDA in the copolymer from 0.5 to 1.0,and the in-plane refractiveindices(n_(TE))range from 1.6366 to 1.6668 and the out-of-plane refractive indices(n_(TM))from 1.6024 to 1.6280 at 632.8 nm.The polymers birefringence(0.0342-0.0388)is almost independent of the 6FDA content of copolymer,which indicated thatthe phthalazinone-containing copolyimides could be suitable to fabricate optical waveguides possessing a low polarizationdependent loss(PDL).展开更多
基金supported by the National Natural Science Foundation of China(Nos.22205105,61874053,22075136)National Key Basic Research Program of China(No.2020YFA0709900)Jiangsu Provincial Postgraduate Scientific Research Innovation Program(No.KYCX24_1649).
文摘Improving the optoelectronic behavior and stress-deformation stability of conjugated materials is crucial for the realization of their potential applications in flexible optoelectronics.To tune the emission behavior and mechanical property of molecular crystals simultaneously via supramolecular salt strategy is rarely reported,which is very important to improve their photophysical behavior and softness for the fabrication of flexible light-emitting device.Herein,supramolecular salt approach has been successfully applied to synthesize two elastic organic fluorescent crystals(CMOH-Py-Cl and CMOH-Py-Br)derived from non-emissive and brittle pyridine-substituted coumarin derivative(CMOH-Py).Their elastic properties can be attributed to the prevalent presence of numerous weak interactions introduced by halogen atoms,which are beneficial to the absorption and release of mechanical energy.Furthermore,density functional theory(DFT)calculations demonstrated a narrowing of the HOMO-LUMO energy gaps from CMOH-Py to CMOH-Py-Cl/CMOH-Py-Br via supramolecular salt approach.Finally,the application of flexible crystal materials in the field of optical waveguides has been investigated.The transformation of crystals in terms of photophysical and mechanical properties,achieved by the supramolecular salt approach,offers novel insights into the design and construction of flexible crystalline materials,providing a new path for the development of next-generation smart materials.
基金supported by the Postgraduate Research and Innovation Program of Jiangsu Province,China(Grant No.KYCX241133)the National Natural Science Foundation of China(Grant No.11405041)+1 种基金the Key Research and Development Program of Jiangxi Province,China(Grant No.20223BBE51020)the Opening Fund of Key Laboratory of Rare Earths(Chinese Academy of Sciences).
文摘Integrating the magneto-optical effect into a waveguide-based photonic device becomes more and more interesting.In the work,the planar optical waveguide firstly was prepared in a terbium gallium garnet crystal(TGG)via the proton implantation with the energy of 4×10^(-1)MeV and the fluence of 6×10^(8)ions/μm^(2).Subsequently,a femtosecond laser with a central wavelength of 800 nm and a power of 3 mW was used to ablate the surface of the planar waveguide,forming the ridge optical waveguide.The dark-mode curve of the planar waveguide was measured by a prism coupling technique.The top-view morphology of the ridge waveguide was observed via a Nikon microscope.The mode field distributions of the planar and ridge waveguides were obtained by an end-face coupling system,and the propagation losses of the two waveguides were measured to be 2.26 dB/cm and 2.58 dB/cm,respectively.The Verdet constants were measured to be-72.7°/T·cm for the TGG substrate and-60.7°/T·cm for the ridge waveguide.The TGG waveguides have a potential in the fabrication of magneto-optical waveguide devices.
文摘Ferrimagnetic materials exhibiting remanence can be used to achieve unidirectional electromagnetic-field propagation in the form of magnetoplasmons(MPs)in the subwavelength regime.This study investigates the MP properties and various guiding modes in a hollow cylindrical waveguide made of materials that exhibit remanence.Pattern analysis and numerical simulations are used to demonstrate that dispersion relationships and electromagnetic-field distribution are strongly affected by the operating frequency and physical dimensions of the structure.In addition,the existence of two different guiding modes is proved,namely regular and surface-wave modes.By adjusting the operating frequency and reducing the diameter of the hollow cylinder,the regular mode can be suppressed so as to only retain the surface-wave mode,which enables unidirectional MP propagation in the cylindrical waveguide.Moreover,the unidirectional surface-wave mode is robust to backscattering due to surface roughness and defects,which makes it very useful for application in field-enhancement devices.
文摘Optical waveguides in silica-on-silicon are one of the key elements in optical communications.The processes of deep etching silica waveguides using resist and metal masks in RIE plasma are investigated.The etching responses,including etching rate and selectivity as functions of variation of parameters,are modeled with a 3D neural network.A novel resist/metal combined mask that can overcome the single-layer masks’ limitations is developed for enhancing the waveguides deep etching and low-loss optical waveguides are fabricated at last.
文摘We propose and fabricate a vertically integrated thermo-optic waveguide switch. It controls the optical path between two vertically stacked waveguides using the thermo-optic effect of optical polymer. The measured crosstalk is less than -10 dB.
基金The National Natural Science Foundation of China(No.60977038)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20110092110016)+1 种基金the National Basic Research Program of China(973Program)(No.2011CB302004)the Foundation of Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology of Ministry of Education of China(No.201204)
文摘Based on attenuated total reflection （ATR） and thermo-optic effect, the polymeric thin film planar optical waveguide is used as the temperature sensor, and the factors influencing the sensitivity of the temperature sensor are comprehensively analyzed. Combined with theoretical analysis and experimental investigation, the sensitivity of the temperature sensor is related to the thicknesses of the upper cladding layer, the waveguide layer, the optical loss of the polymer material and the guided wave modes. The results show that the slope value about reflectivity and temperature, which stands for the sensitivity of the polymer thin film temperature sensor, is associated with the waveguide film thickness and the guided wave modes, and the slope value is the highest in the zero reflectance of a certain transverse electric （TE） mode. To improve the sensitivity of the temperature sensor, the sensor＇s working incident light exterior angle α should be chosen under a certain TE mode with the reflectivity to be zero. This temperature sensor is characterized by high sensitivity and simple structure and it is easily fabricated.
基金financial support from National Natural Science Foundation of China(No.61775120).
文摘Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established based on crystalline materials,particularly,are opening exciting possibilities and opportunities in photonic chips by facilitating their on-chip integration with different functionalities and highly compact photonic circuits.Femtosecond-laser-direct writing(FsLDW),as a true three-dimensional(3D)micromachining and microfabrication technology,allows rapid prototyping of on-demand waveguide geometries inside transparent materials via localized material modification.The success of FsLDW lies not only in its unsurpassed aptitude for realizing 3D devices but also in its remarkable material-independence that enables cross-platform solutions.This review emphasizes FsLDW fabrication of waveguide structures with 3D layouts in dielectric crystals.Their functionalities as passive and active photonic devices are also demonstrated and discussed.
基金FAPES(320/2020 and 84336650)CNPq(304049/2019-0 and 427054/2018-4)+2 种基金Fundação para a Ciência e a Tecnologia(FCT)through the DigiAqua project-PTDC/EEIEEE/0415/2021.C.FCT through the CEECIND/00034/2018(iFish project)developed within the scope of the project i3N,UIDB/50025/2020&UIDP/50025/2020financed by national funds through the FCT/MEC.
文摘This paper presents the development of a bioinspired multifunctional flexible optical sensor(BioMFOS)as an ultrasensitive tool for force(intensity and location)and orientation sensing.The sensor structure is bioinspired in orb webs,which are multifunctional devices for prey capturing and vibration transmission.The multifunctional feature of the structure is achieved by using transparent resins that present both mechanical and optical properties for structural integrity and strain/deflection transmission as well as the optical signal transmission properties with core/cladding configuration of a waveguide.In this case,photocurable and polydimethylsiloxane(PDMS)resins are used for the core and cladding,respectively.The optical transmission,tensile tests,and dynamic mechanical analysis are performed in the resins and show the possibility of light transmission at the visible wavelength range in conjunction with high flexibility and a dynamic range up to 150 Hz,suitable for wearable applications.The BioMFOS has small dimensions(around 2 cm)and lightweight(0.8 g),making it suitable for wearable application and clothing integration.Characterization tests are performed in the structure by means of applying forces at different locations of the structure.The results show an ultra-high sensitivity and resolution,where forces in theμN range can be detected and the location of the applied force can also be detected with a sub-millimeter spatial resolution.Then,the BioMFOS is tested on the orientation detection in 3D plane,where a correlation coefficient higher than 0.9 is obtained when compared with a gold-standard inertial measurement unit(IMU).Furthermore,the device also shows its capabilities on the movement analysis and classification in two protocols:finger position detection(with the BioMFOS positioned on the top of the hand)and trunk orientation assessment(with the sensor integrated on the clothing).In both cases,the sensor is able of classifying the movement,especially when analyzed in conjunction with preprocessing and clustering techniques.As another wearable application,the respiratory rate is successfully estimated with the BioMFOS integrated into the clothing.Thus,the proposed multifunctional device opens new avenues for novel bioinspired photonic devices and can be used in many applications of biomedical,biomechanics,and micro/nanotechnology.
基金Supported by the National Natural Science Foundation of China(No.20965008)
文摘A sensitive optical waveguide（OWG） sensor which can be used to detect volatile organic compounds（VOCs） was presented.The sensing device（element） was fabricated by means of the immobilization of polyvinyl pyrrolidone（PVP）-cyclodextrin（CD） composite film over a single-mode potassium ion exchanged glass OWG via spin-coating method.The sensor shows higher response to styrene gas than to other VOCs and displays a linear response to styrene gas in a range of 1―1000 μL/L.
基金the National Natural Science Foundation of China(Nos.21971185,52173177)this project is also funded by the Collaborative Innovation center of Suzhou Nano Science and Technology(CIC-Nano)by the"111"Project of the State Administration of Foreign Experts Affairs of China。
文摘Micro-nano-level photonic waveguide regulation is essential for future on-chip photonic integrated systems and is still of great challenges.We report a molecular design strategy,changing the position of the methyl substituent makes the arrangement of the three isomer molecules different in their respective crystals.Based on this strategy,three sheet-like crystals with different polygonal morphologies were prepared via solution self-assembly approach.The in-depth optical measurements demonstrated that these three microsheet crystals have different 2D optical waveguide performances related to the shapes.Our work provides a feasible design strategy and material preparation method for realizing precise 2D optical waveguide modulation,which lays the foundation for complex photonic integrated systems in the future.
基金Projects(51475479,51075402)supported by the National Natural Science Foundation of ChinaProject(2012AA040406)supported by the National High Technology Research and Development Program of China+2 种基金Project(20110162130004)supported by the Research Fund for the Doctoral Program of Higher Education of ChinaProject(14JJ2010)supported by the Natural Science Foundation of Hunan Province,ChinaProject(GZKF-201401)supported by the Open Project of Stage Key Laboratory of Fluid Power Transmission and Control(Zhejiang University),China
文摘The alignment coupling between optical waveguide chips and optical fiber arrays is the basis of the alignment coupling of planar optical waveguide devices, and the precise position detection with angle and spacing adjustments is one of the key steps of alignment coupling. A methodology for position detection, and angle and spacing adjustment was proposed for optical waveguide chips and optical fiber arrays based on machine vision. The experimental results show angle detection precision levels higher than 0.05°, line detection precision levels higher than 0.1 μm, and detection time less than 2 s. Therefore, the system developed herein meets the precise requirements necessary for position detection, and angle and spacing adjustments for optical waveguide chips and optical fiber arrays.
基金supported by the National High Technology Research and Development Program of China (No.2009AA03Z413)
文摘In order to reduce transmission loss of the optical waveguide in Mach-Zehnder (M-Z) electro-optical (EO) polymer modulator,the basic iterative formula of semi-vector finite-difference beam propagation method (FD-BPM) is obtained from the scalar wave equation. The transition waveguide is combined with S-type bend branch waveguide for the M-Z EO modulator in the branch waveguide. The effects of structure parameters such as ridge width,length of the branch waveguide and interferometer spacing on the transmission loss are systematically studied by using the semi-vector FD-BPM method. The structure is optimized as an S-sine bend branch waveguide,with rib width w=7μm,length of branch waveguide L=1200μm and interferometer spacing G=22 μm. The results show that the optimized structure can reduce transmission loss to 0.083 dB,which have a certain reference value to the design of optical waveguide in M-Z polymer modulator.
文摘Calculation shown that the refraction index of Ge_0.6Si_0.4/Sistrained-layer superlattice n≈3.64, when L_w=9 nm and L_b=24 nm. Analgorithm of numerical iteration for effective refraction index isemployed to obtain different effective refraction indexes atdifferent thickness (L). As a result, the thickness ofGe_0.6Si_0.4/Si strained-layer superlattice optical waveguide, L≤363nm, can be determined, which is very important for designingwaveguide devices. An optical waveguide can be made into a nanometerdevice by using Ge_0.6 Si_0.4/Si strained-layer superlattice.
基金Project supported by Natural Science Foundation of the Department of Science & Technology of Fujian Province of China (GrantNo 2007F5040)
文摘This paper analyzes the characteristic of matching efficiency between the fundamental mode of two kinds of optical waveguides and its Gaussian approximate field.Then, it presents a new method where the mode-field half-width of Caussian approximation for the fundamental mode should be defined according to the maximal matching efficiency method. The relationship between the mode-field half-width of the Gaussian approximate field obtained from the maximal matching efficiency and normalized frequency is studied; furthermore, two formulas of mode-field half-widths as a function of normalized frequency are proposed.
基金Project(52175445) supported by the National Natural Science Foundation of ChinaProject(ZZYJKT2020-09) supported by the State Key Laboratory of High Performance Complex Manufacturing (Central South University),China+1 种基金Projects(2020JJ4247, 2022JJ30743) supported by the Natural Foundation of Hunan Province,ChinaProject(1053320190337) supported by the Fundamental Research Funds for the Central University,China。
文摘Electron beam lithography(EBL) is a key technology in the fabrication of nanoscale silicon optical waveguide. The influence of exposure dose, the main process parameter of EBL, on the structure profile of poly-methyl methacrylate(PMMA) after development was studied using a silicon on insulator(SOI) wafer with 220 nm top silicon as the substrate. The relationship between exposure dose and structure pattern width after development was analyzed according to the measurement results. The optimum exposure dose of 220 μC/cm^(2) was found to obtain a final structure consistent with the designed mask value through subsequent processes. At the same time, according to the image segmentation curve tracking technology, the contour extraction process of the dose test results was carried out, and the relationship among mask design value, exposure dose and two-dimensional roughness of boundary contour was analyzed, which can provide reference for the subsequent electron beam lithography of the same substrate material.
文摘Based on the polynomial interpolation, a new finite difference （FD） method in solving the full-vectorial guidedmodes for step-index optical waveguides is proposed. The discontinuities of the normal components of the electric field across abrupt dielectric interfaces are considered in the absence of the limitations of scalar and semivectorial approximation, and the present PD scheme can be applied to both uniform and non-uniform mesh grids. The modal propagation constants and field distributions for buried rectangular waveguides and optical rib waveguides are presented. The hybrid nature of the vectorial modes is demonstrated and the singular behaviours of the minor field components in the corners are observed. Moreover, solutions are in good agreement with those published early, which tests the validity of the present approach.
基金Project supported by the Postgraduate Research and Practice Innovation Program of Jiangsu Province,China(Grant No.SJCX210274)the National Natural Science Foundation of China(Grant Nos.11405041 and 61905119)+1 种基金the Scientific Research Foundation for Youths Supported by Jiangxi Province Science Foundation,China(Grant No.20192BAB217015)the University Natural Science Research Project of Jiangsu Province,China(Grant No.19KJB140013)。
文摘Terbium gallium garnet(Tb_(3)Ga_(5)O_(12),TGG)crystal can be used to fabricate various magneto-optical devices due to its optimal Faraday effect.In this work,400-keV He^(+)ions with a fluence of 6.0×10^(16)ions/cm^(2)are irradiated into the TGG crystal for the planar waveguide formation.The precise diamond blade dicing with a rotation speed of 2×10^(4)rpm and a cutting velocity of 0.1 mm/s is performed on the He^(+)-implanted TGG planar waveguide for the ridge structure.The darkmode spectrum of the He^(+)-implanted TGG planar waveguide is measured by the prism-coupling method,thereby obtaining the relationship between the reflected light intensity and the effective refractive index.The refractive index profile of the planar waveguide is reconstructed by the reflectivity calculation method.The near-field light intensity distribution of the planar waveguide and the ridge waveguide are recorded by the end-face coupling method.The He^(+)-implanted and diamond blade-diced TGG crystal planar and ridge waveguides are promising candidates for integrated magneto-optical devices.
基金support from NSFC China (grants 61275188,61378089 and 81171375)the key project of Guangdong province (2012A080203008)+1 种基金the Basic Research Program of Shenzhen City (JC201105201121A)State Key Laboratory Open Foundation Issue,China (grant 12K05ESPCT).
文摘We proposed a new saccharides sensor developed by symmetrical optical waveguide(SOW)-based surface plasmon resonance(SPR).This unique MgF_(2)/Au/MgF_(2)/Analyte film structure results in longer suface plasmon wave(SPW)propagation lengths and depths,leading to an increment of resolution.In this paper,we managed to decorate the dielectric interface(MgF_(2) layer)by depositing a thin polydopamine film as surface adherent that provides a platform for secondary reactions with the probe molecule.3-Aminophenylboronic acid(3-PBA)is chosen to be the saccharides sense probe molecule in the present work.The aqueous huumnor of Diabetes and Cataract patient whose blood glucose level is normal are analyzed and the results dermonstrated that this sensor shows great potential in monitoring the blood siugar and can be adapted in the field of biological monitoring in the future.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 60272075 and 60478014)the National High Technology Research and Development Program of China (Grant No 2007AA12Z112)partially supported by the program of excellent team in Harbin Institute of Technology,China
文摘This paper derives the dispersion relation of microring coupled-resonator optical waveguides （CROWs） without any approximation by using the transfer matrix method. Based on the established dispersion relation of CROWs it obtains the slow group velocity and dispersion coefficient. It finds that the effect Of dispersion on optical pulses can be adjusted to balance the effect of nonlinearity by changing coupling coefficient or loss, so optical soliton with group delay can be obtained in microring CROWs. The optical soliton with group delay is of great significance for applications of microring CROWs in delay lines and optical buffers of future all-optical communication systems.
基金This work was supported by the National Natural Science Foundation of China(No.50143013).
文摘A series of fluorinated copolyimides containing phthalazinone moieties were prepared from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride(6FDA),3,3'4,4'-benzophenone-tetracarboxylic dianhydride(BPDA)and2-(4-aminophenyl)-4-[4-(4-aminophenoxyl)phenyl]-2,3-phthalazin-1-one(DHPZ-2NH_2)for making polymeric opticalwaveguides.The resulting copolymers containing 0-50 mo1% BPDA/DHPZ-2NH_2 show good solubility and are soluble insome organic polar aprotic solvents.The copolyimides also present excellent thermal stability.These polymers possess highglass transition temperature higher than 603 K and high decomposition temperature above 742 K determined by differentialscanning calorimetry and thennogravimetric analysis,respectively,under a nitrogen atmosphere.Their refractive indicescould be controlled by varying the ratio of 6FDA and BPDA in the copolymer from 0.5 to 1.0,and the in-plane refractiveindices(n_(TE))range from 1.6366 to 1.6668 and the out-of-plane refractive indices(n_(TM))from 1.6024 to 1.6280 at 632.8 nm.The polymers birefringence(0.0342-0.0388)is almost independent of the 6FDA content of copolymer,which indicated thatthe phthalazinone-containing copolyimides could be suitable to fabricate optical waveguides possessing a low polarizationdependent loss(PDL).
