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
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
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
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
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
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 simple setup for the measurement of transmission loss in polymer thin film optical waveguides is described. A new electro-optic polymer film has been prepared. The transmission loss of the film is measured before an...A simple setup for the measurement of transmission loss in polymer thin film optical waveguides is described. A new electro-optic polymer film has been prepared. The transmission loss of the film is measured before and after corona poling. And the loss is determined to be 1.84 dB/cm and 2.14 dB/cm, respectively.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
Femtosecond laser inscription or writing has been recognized as a powerful technique to engineer various materials toward a number of applications.By efficient modification of refractive indices of dielectric crystals...Femtosecond laser inscription or writing has been recognized as a powerful technique to engineer various materials toward a number of applications.By efficient modification of refractive indices of dielectric crystals,optical waveguides with diverse configurations have been produced by femtosecond laser writing.The waveguiding properties depend not only on the parameters of the laser writing but also on the nature of the crystals.The mode profile tailoring and polarization engineering are realizable by selecting appropriate fabrication conditions.In addition,regardless of the complexity of crystal refractive index changes induced by ultrafast pulses,several three-dimensional geometries have been designed and implemented that are useful for the fabrication of laser-written photonic chips.Some intriguing devices,e.g.,waveguide lasers,wavelength converters,and quantum memories,have been made,exhibiting potential for applications in various areas.Our work gives a concise review of the femtosecond laser-inscribed waveguides in dielectric crystals and focuses on the recent advances of this research area,including the fundamentals,fabrication,and selected photonic applications.展开更多
Optical wave-guiding structures that are non-uniform in the propagation direction are fundamental building blocks of integrated optical circuits.Numerical simulation of lightwaves propagating in these structures is an...Optical wave-guiding structures that are non-uniform in the propagation direction are fundamental building blocks of integrated optical circuits.Numerical simulation of lightwaves propagating in these structures is an essential tool to engineers designing photonic components.In this paper,we review recent developments in the most widely used simulation methods for frequency domain propagation problems.展开更多
Organic/inorganic material has attracted great attentions because its importance as photonic materials. We report on our recent results on organic/inorganic hybrid sol-gel materials and optical waveguides like splitte...Organic/inorganic material has attracted great attentions because its importance as photonic materials. We report on our recent results on organic/inorganic hybrid sol-gel materials and optical waveguides like splitter, thermo-optic switch and micro-cavity laser.展开更多
SiO_2/TiO_2/methylcellulose composite materials processed by the sol-gel technique were studied for optical waveguide applications. With the help of methylcellulose, an organic binder, SiO2/TiO2/methylcellulose hybrid...SiO_2/TiO_2/methylcellulose composite materials processed by the sol-gel technique were studied for optical waveguide applications. With the help of methylcellulose, an organic binder, SiO2/TiO2/methylcellulose hybrid thick films were prepared by a single spin-coating processes. After annealing at 70 °C for an hour, 2.5-μm crack-free and dense organic-inorganic hybrid optical films with a refractive index of 1.537 were achieved. Optical losses of plane waveguide made up of those films and ordinary slide glass substrate are around 0.3 dB/cm at 650 nm. Scanning electronmicroscopy (SEM) and UV-visible spectroscopy (UV-VIS), have been used to characterize the thick films.展开更多
Ultralong phosphorescent materials have numerous applications across biological imaging, lightemitting devices, X-ray detection and anti-counterfeiting. Triplet-state molecular phosphorescence typically accompanies th...Ultralong phosphorescent materials have numerous applications across biological imaging, lightemitting devices, X-ray detection and anti-counterfeiting. Triplet-state molecular phosphorescence typically accompanies the singlet-state fluorescence during photoluminescence, and it is still difficult to achieve direct triplet photoemission as ultralong room temperature phosphorescence(RTP). Here, we have designed Zn-IMDC(IMDC, 4,5-imidazoledicarboxylic acid) and Cd-IMDC, two-dimensional(2D)hydrogen-bond organized metal–organic crystalline microsheets that exhibit rarely direct ultralong RTP upon UV excitation, benefiting from the appropriate heavy-atom effect and multiple triplet energy levels. The excitation-dependent and thermally stimulated ultralong phosphorescence endow the metal–organic systems great opportunities for information safety application and temperature-gated afterglow emission. The well-defined 2D microsheets present color-tunable and anisotropic optical waveguides under different excitation and temperature conditions, providing an effective way to obtain intelligent RTP-based photonic systems at the micro-and nano-scales.展开更多
In this study,we design and numerically investigate a novel all optical D flip-flop(AODFF)based on linear photonic crystal(LPhC)structure that is composed of optical waveguides using the finite difference time domain(...In this study,we design and numerically investigate a novel all optical D flip-flop(AODFF)based on linear photonic crystal(LPhC)structure that is composed of optical waveguides using the finite difference time domain(FDTD)method.The proposed structure has the hexagonal close packed of 16×20 circular rods that are suspended in the air substrate with a lattice constant of 606 nm.The plane wave expansion(PWE)method is used to obtain the band diagram for AODFF at an operating wavelength of 1550 nm.The proposed optical flip-flop achieves a low delay time of 0.2 ps and a high contrast ratio(CR)of 10.33 dB.The main advantage of this design is that the input power as low as 1 mW/μm^(2) is sufficient for its operation,since no nonlinear rods are included.In addition,the footprint of the proposed AODFF is 100μm^(2),which is smaller compared to the structures reported in the literature,and it has a fast switching frequency of 5 Tbit/s.展开更多
Optical waveguide of organic micro/nanocrystals is one of crucial elements in miniaturized integrated photonics.One-dimensional(1D)organic crystals with various optical features have attracted increasing interests tow...Optical waveguide of organic micro/nanocrystals is one of crucial elements in miniaturized integrated photonics.One-dimensional(1D)organic crystals with various optical features have attracted increasing interests towards promising photonic devices,such as multichannel signal converter,organic field-effect optical waveguide,sensitive detector,and optical logic gate.Therefore,a summary about the 1D organic micro/nanocrystals based optical waveguide is important for the rational design and fabrication of novel optical devices towards optoelectronics applications.Herein,recent advances of optical waveguide based on 1D organic micro/nanocrystals with solid,flexible,hollow,uniformly doped,core-shell,multiblock and branched structures are summarized from the aspects of the waveguide properties and applications in photonic devices.Furthermore,we presented our personal view about the expectation of future development in 1D organic optical waveguide for the photonic applications.展开更多
Active organic optical waveguide materials(OOWMs)incorporating room temperature phosphorescence(RTP)hold significant promise for diverse applications in photonic and optoelectronic devices.Despite this potential,reali...Active organic optical waveguide materials(OOWMs)incorporating room temperature phosphorescence(RTP)hold significant promise for diverse applications in photonic and optoelectronic devices.Despite this potential,realizing active RTP optical waveguides with large-sized ordered structures and minimal light loss remains a formidable challenge.To address this issue,we present a groundbreaking thermoplastic active OOWM with low light loss,leveraging room temperature phosphorescent liquid crystalline polymer(LCP).This innovative material can be easily synthesized through the copolymerization of phosphorescent and liquid crystalline monomers.The resulting RTP copolymer exhibits a nematic liquid crystal phase with a phosphorescence lifetime of approximately 0.15 ms and an afterglow duration of around 1 second.Leveraging the excellent processability of LCP,we successfully produce meter-scale fibers via melt spinning.These RTP LCP fibers,characterized by a high orientation of mesogens along the fiber axis,demonstrate superior light confinement and efficient light conduction compared to unoriented samples,resulting in a low optical loss coefficient of 0.13 dB/mm.Furthermore,the thermal responsiveness of the RTP LCP optical waveguide enables its use as a photo switch.This pioneering work paves the way for the design of new OOWMs tailored for advanced photonics and optoelectronics devices.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
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
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
With the rapid development of optical elements with large capacity and high speed, the network architecture is of great importance in determing the performance of wavelength division multiplexing passive optical netwo...With the rapid development of optical elements with large capacity and high speed, the network architecture is of great importance in determing the performance of wavelength division multiplexing passive optical network （WDM-PON）. This paper proposes a switching struc^re based on the tunable wavelength converter （TWC） and the ar- rayed-waveguide grating （AWG） for WDM-PON, in order to provide the function of opitcal virtual private network （OVPN）. Using the tunable wavelength converter technology, this switch structure is designed and works between the optical line terminal （OLT） and optical network units （ONUs） in the WDM-PON system. Moreover, the wavelength assignment of upstream/downstream can be realized and direct communication between ONUs is also allowed by privite wavelength channel. Simulation results show that the proposed TWC and AWG based switching structure is able to achieve OVPN function and to gain better performances in terms of bite error rate （BER） and time delay.展开更多
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).
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 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.
文摘A simple setup for the measurement of transmission loss in polymer thin film optical waveguides is described. A new electro-optic polymer film has been prepared. The transmission loss of the film is measured before and after corona poling. And the loss is determined to be 1.84 dB/cm and 2.14 dB/cm, respectively.
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.
基金financially supported by the National Natural Science Foundation of China (Nos. 12174222 and 61775120)the Natural Science Foundation of Shandong Province (ZR2021ZD02)Taishan Scholars Program of Shandong Province
文摘Femtosecond laser inscription or writing has been recognized as a powerful technique to engineer various materials toward a number of applications.By efficient modification of refractive indices of dielectric crystals,optical waveguides with diverse configurations have been produced by femtosecond laser writing.The waveguiding properties depend not only on the parameters of the laser writing but also on the nature of the crystals.The mode profile tailoring and polarization engineering are realizable by selecting appropriate fabrication conditions.In addition,regardless of the complexity of crystal refractive index changes induced by ultrafast pulses,several three-dimensional geometries have been designed and implemented that are useful for the fabrication of laser-written photonic chips.Some intriguing devices,e.g.,waveguide lasers,wavelength converters,and quantum memories,have been made,exhibiting potential for applications in various areas.Our work gives a concise review of the femtosecond laser-inscribed waveguides in dielectric crystals and focuses on the recent advances of this research area,including the fundamentals,fabrication,and selected photonic applications.
基金the Research Grants Council of Hong Kong Special Administrative Region,China(Project No.CityU 101804).
文摘Optical wave-guiding structures that are non-uniform in the propagation direction are fundamental building blocks of integrated optical circuits.Numerical simulation of lightwaves propagating in these structures is an essential tool to engineers designing photonic components.In this paper,we review recent developments in the most widely used simulation methods for frequency domain propagation problems.
文摘Organic/inorganic material has attracted great attentions because its importance as photonic materials. We report on our recent results on organic/inorganic hybrid sol-gel materials and optical waveguides like splitter, thermo-optic switch and micro-cavity laser.
基金This work was supported by the National Natu- ral Science Foundation of China (No. 90206002 and 90201013)the National "863" Project of China (No. 2002AA313030).
文摘SiO_2/TiO_2/methylcellulose composite materials processed by the sol-gel technique were studied for optical waveguide applications. With the help of methylcellulose, an organic binder, SiO2/TiO2/methylcellulose hybrid thick films were prepared by a single spin-coating processes. After annealing at 70 °C for an hour, 2.5-μm crack-free and dense organic-inorganic hybrid optical films with a refractive index of 1.537 were achieved. Optical losses of plane waveguide made up of those films and ordinary slide glass substrate are around 0.3 dB/cm at 650 nm. Scanning electronmicroscopy (SEM) and UV-visible spectroscopy (UV-VIS), have been used to characterize the thick films.
基金supported by the Beijing Municipal Natural Science Foundation(JQ20003)the National Natural Science Foundation of China(21771021,21822501,and 22061130206)+3 种基金the Fok Ying-Tong Education Foundation(171008)the Measurements Fund of Beijing Normal Universitythe State Key Laboratory of Heavy Oil Processing。
文摘Ultralong phosphorescent materials have numerous applications across biological imaging, lightemitting devices, X-ray detection and anti-counterfeiting. Triplet-state molecular phosphorescence typically accompanies the singlet-state fluorescence during photoluminescence, and it is still difficult to achieve direct triplet photoemission as ultralong room temperature phosphorescence(RTP). Here, we have designed Zn-IMDC(IMDC, 4,5-imidazoledicarboxylic acid) and Cd-IMDC, two-dimensional(2D)hydrogen-bond organized metal–organic crystalline microsheets that exhibit rarely direct ultralong RTP upon UV excitation, benefiting from the appropriate heavy-atom effect and multiple triplet energy levels. The excitation-dependent and thermally stimulated ultralong phosphorescence endow the metal–organic systems great opportunities for information safety application and temperature-gated afterglow emission. The well-defined 2D microsheets present color-tunable and anisotropic optical waveguides under different excitation and temperature conditions, providing an effective way to obtain intelligent RTP-based photonic systems at the micro-and nano-scales.
文摘In this study,we design and numerically investigate a novel all optical D flip-flop(AODFF)based on linear photonic crystal(LPhC)structure that is composed of optical waveguides using the finite difference time domain(FDTD)method.The proposed structure has the hexagonal close packed of 16×20 circular rods that are suspended in the air substrate with a lattice constant of 606 nm.The plane wave expansion(PWE)method is used to obtain the band diagram for AODFF at an operating wavelength of 1550 nm.The proposed optical flip-flop achieves a low delay time of 0.2 ps and a high contrast ratio(CR)of 10.33 dB.The main advantage of this design is that the input power as low as 1 mW/μm^(2) is sufficient for its operation,since no nonlinear rods are included.In addition,the footprint of the proposed AODFF is 100μm^(2),which is smaller compared to the structures reported in the literature,and it has a fast switching frequency of 5 Tbit/s.
基金The National Natural Science Foundation of China(Nos.21703148 and 21971185)the Natural Science Foundation of Jiangsu Province(BK20170330).
文摘Optical waveguide of organic micro/nanocrystals is one of crucial elements in miniaturized integrated photonics.One-dimensional(1D)organic crystals with various optical features have attracted increasing interests towards promising photonic devices,such as multichannel signal converter,organic field-effect optical waveguide,sensitive detector,and optical logic gate.Therefore,a summary about the 1D organic micro/nanocrystals based optical waveguide is important for the rational design and fabrication of novel optical devices towards optoelectronics applications.Herein,recent advances of optical waveguide based on 1D organic micro/nanocrystals with solid,flexible,hollow,uniformly doped,core-shell,multiblock and branched structures are summarized from the aspects of the waveguide properties and applications in photonic devices.Furthermore,we presented our personal view about the expectation of future development in 1D organic optical waveguide for the photonic applications.
基金financially supported by the National Natural Science Foundation of China(22275158,21975215 and 51921002)the Key Research and Development Program of Hunan Province of China(2023GK2031)+2 种基金the Funding Project of Furong Scholars Award ProgramXiangtan University-Zhuzhou Feilu High-tech Material Technology Co.,Ltd.the Joint Training Base of Industry-Education Integration of Graduate Students。
文摘Active organic optical waveguide materials(OOWMs)incorporating room temperature phosphorescence(RTP)hold significant promise for diverse applications in photonic and optoelectronic devices.Despite this potential,realizing active RTP optical waveguides with large-sized ordered structures and minimal light loss remains a formidable challenge.To address this issue,we present a groundbreaking thermoplastic active OOWM with low light loss,leveraging room temperature phosphorescent liquid crystalline polymer(LCP).This innovative material can be easily synthesized through the copolymerization of phosphorescent and liquid crystalline monomers.The resulting RTP copolymer exhibits a nematic liquid crystal phase with a phosphorescence lifetime of approximately 0.15 ms and an afterglow duration of around 1 second.Leveraging the excellent processability of LCP,we successfully produce meter-scale fibers via melt spinning.These RTP LCP fibers,characterized by a high orientation of mesogens along the fiber axis,demonstrate superior light confinement and efficient light conduction compared to unoriented samples,resulting in a low optical loss coefficient of 0.13 dB/mm.Furthermore,the thermal responsiveness of the RTP LCP optical waveguide enables its use as a photo switch.This pioneering work paves the way for the design of new OOWMs tailored for advanced photonics and optoelectronics devices.
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.
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 High Technical Research and Development Program of China(No.2012AA050804)
文摘With the rapid development of optical elements with large capacity and high speed, the network architecture is of great importance in determing the performance of wavelength division multiplexing passive optical network （WDM-PON）. This paper proposes a switching struc^re based on the tunable wavelength converter （TWC） and the ar- rayed-waveguide grating （AWG） for WDM-PON, in order to provide the function of opitcal virtual private network （OVPN）. Using the tunable wavelength converter technology, this switch structure is designed and works between the optical line terminal （OLT） and optical network units （ONUs） in the WDM-PON system. Moreover, the wavelength assignment of upstream/downstream can be realized and direct communication between ONUs is also allowed by privite wavelength channel. Simulation results show that the proposed TWC and AWG based switching structure is able to achieve OVPN function and to gain better performances in terms of bite error rate （BER） and time delay.
