Herein,an attention-grabbing and up-to-date review related to major multiplexing techniques is presented which in-cludes wavelength division multiplexing(WDM),polarization division multiplexing(PDM),space division mul...Herein,an attention-grabbing and up-to-date review related to major multiplexing techniques is presented which in-cludes wavelength division multiplexing(WDM),polarization division multiplexing(PDM),space division multiplexing(SDM),mode division multiplexing(MDM)and orbital angular momentum multiplexing(OAMM).Multiplexing is a mech-anism by which multiple signals are combined into a shared channel used to showcase the maximum capacity of the op-tical links.However,it is critical to develop hybrid multiplexing methods to allow enhanced channel numbers.In this re-view,we have also included hybrid multiplexing techniques such as WDM-PDM,WDM-MDM and PDM-MDM.It is prob-able to attain N×M channels by utilizing N wavelengths and M guided-modes by simply utilizing hybrid WDM-MDM(de)multiplexers.To the best of our knowledge,this review paper is one of its kind which has highlighted the most prom-inent and recent signs of progress in multiplexing techniques in one place.展开更多
Dielectric resonators are key components in many microwave and millimetre wave circuits and applications, including high-Q filters and frequency-determining elements for precision frequency synthesis. Multilayered and...Dielectric resonators are key components in many microwave and millimetre wave circuits and applications, including high-Q filters and frequency-determining elements for precision frequency synthesis. Multilayered and bulk low-loss single crystal and polycrystalline dielectric structures have become very important for designing these devices. Proper design requires careful electromagnetic characterisation of low-loss material properties. This includes exact simulation with precision numerical software and precise measurements of resonant modes. For example, we have developed the Whispering Gallery mode technique, which has now become the standard for characterizing low-loss structures. This paper will review some of the common characterisation techniques used in the microwave to millimetre wave frequency regime.展开更多
An integrated optical chip for fiber optical gyroscope(FOG) is designed and fabricated on GaAs.To achieve a high modulation efficiency and a small chip size,a deeply etched waveguide structure is employed,and accordin...An integrated optical chip for fiber optical gyroscope(FOG) is designed and fabricated on GaAs.To achieve a high modulation efficiency and a small chip size,a deeply etched waveguide structure is employed,and accordingly a multimode interference(MMI) coupler is used as the 1 × 2 power splitter.The size of the chip is about 8.5 mm × 0.5 mm,which is much smaller than that of LiNbO3-based chips.The experimental results show that the extinction ratio(ER) of the TE mode to the TM mode is over 26 dB and the value of Vπ·L of the phase modulators is 18 V·cm.The method to further lower Vπ is discussed.展开更多
An LED driving circuit in accurate proportional current sampling mode is designed and fabricated based on CSMC 0.5 μm standard CMOS technology. It realizes accurate sensing of sampling current variation with output d...An LED driving circuit in accurate proportional current sampling mode is designed and fabricated based on CSMC 0.5 μm standard CMOS technology. It realizes accurate sensing of sampling current variation with output driving current. A better constant output current characteristic is achieved by using an amplifier to clamp the drain voltage of both the sampling MOSFET and power MOSFET to the same value with feedback control. Small signal equivalent circuit analysis shows that the small signal output resistance in the accurate proportional current sampling mode circuit is much larger than that in a traditional proportional current sampling mode circuit, and circuit stability could be assured. Circuit simulation and chip testing results show that when the LED driving current is 350 mA and the power supply is 6 V with ± 10% variation, the stability of the output constant current of the accurate proportional current sampling mode LED driving IC will show 41% improvement over that of a traditional proportional current sampling mode LED driving IC.展开更多
Luminescent properties of Y2O3 and LaAlO3 nanopowders doped with Pr^3＋ ions and PMMA-based composite materials doped with these powders were reported. The set of active nanopowders differing in praseodymium ions conc...Luminescent properties of Y2O3 and LaAlO3 nanopowders doped with Pr^3＋ ions and PMMA-based composite materials doped with these powders were reported. The set of active nanopowders differing in praseodymium ions concentration was prepared using sol-gel method and carefully characterized with respect to emission properties in the visible spectral range. In particular, the excitation and emission spectra were measured together with fluorescence decay profiles and the differences between optical properties of these materials were discussed and compared with data available for bulk materials. Finally, the PMMA-based composite materials doped with Pr^3＋：Y2O3 and Pr^3＋：LaAlO3 nanopowders were manufactured and characterized. The obtained results showed that polymer composites doped with active nanopowders in general tended to keep the luminescent properties of the original nanopowders.展开更多
Fiber optofluidic laser(FOFL)integrates optical fiber microcavity and microfluidic channel and provides many unique advantages for sensing applications.FOFLs not only inherit the advantages of lasers such as high sens...Fiber optofluidic laser(FOFL)integrates optical fiber microcavity and microfluidic channel and provides many unique advantages for sensing applications.FOFLs not only inherit the advantages of lasers such as high sensitivity,high signal-to-noise ratio,and narrow linewidth,but also hold the unique features of optical fiber,including ease of integration,high repeatability,and low cost.With the development of new fiber structures and fabrication technologies,FOFLs become an important branch of optical fiber sensors,especially for application in biochemical detection.In this paper,the recent progress on FOFL is reviewed.We focuse mainly on the optical fiber resonators,gain medium,and the emerging sen sing applicatio ns.The prospects for FOFL are also discussed.We believe that the FOFL sensor provides a promising technology for biomedical analysis and environmental monitoring.展开更多
In this Letter,a method for shape visualization of small objects(microscopic)in the form of a hologram is presented.It consists of a standard optical set-up for small object registration(i.e.,stereoscopic or biologica...In this Letter,a method for shape visualization of small objects(microscopic)in the form of a hologram is presented.It consists of a standard optical set-up for small object registration(i.e.,stereoscopic or biological microscope).The focus stacking technique is used to obtain a series of images with increased depth of field and on them a shape reconstruction procedure(structure from motion,SfM)is made.With use of a dense cloud of points,a sequence of parallax-related images suitable for Geola’s digital holographic printing is generated.The holographic printer produces single-parallax holographic(full three-dimensional)images of real or virtual objects.展开更多
A CMOS compatible P＋/Nwell/Psub double junction photodiode pixel was proposed, which can effi- ciently detect fluorescence from CsI（T1） scintillation in an X-ray sensor. Photoelectric and spectral responses of P＋/...A CMOS compatible P＋/Nwell/Psub double junction photodiode pixel was proposed, which can effi- ciently detect fluorescence from CsI（T1） scintillation in an X-ray sensor. Photoelectric and spectral responses of P＋/Nwell, NweE1/Psub and P＋/Nwell/Psub photodiodes were analyzed and modeled. Simulation results show P＋/Nweu/Psub photodiode has larger photocurrent than P＋/Nwetl photodiode and Nweu/Psub photodiode, and its spectral response is more in accordance with CsI（T1） fluorescence spectrum. Improved P＋/Nweu/Psub photodiode detecting CsI（T1） fluorescence was designed in CSMC 0.5 #m CMOS process, CTIA （capacitive transimpedance amplifier） architecture was used to readout photocurrent signal. CMOS X-ray sensor IC prototype contains 8 × 8 pixel array and pixel pitch is 100 × 100 μm2. Testing results show the dark current of the improved P＋/Nwell/Psub photodiode （6.5 pA） is less than that of P＋/Nwell and P＋/Nwell/Psub photodiodes （13 pA and 11 pA respectively）. The sen- sitivity of P＋/Nwell/Psub photodiode is about 20 pA/lux under white LED. The spectrum response of P＋/Nwell/Psub photodiode ranges from 400 nm to 800 nm with a peak at 532 nm, which is in accordance with the fluorescence spectrum of Csl（T1） in an indirect X-ray sensor. Preliminary testing results show the sensitivity of X-ray sensor IC under Cu target X-ray is about 0.21 V.m^2/W or 5097e-/pixel @ 8.05 keV considering the pixel size, integration time and average energy of X-ray photons.展开更多
We propose a polarization-insensitive design of a hybrid plasmonic waveguide(HPWG)optimized at the 3.392µm wavelength which corresponds to the absorption line of methane gas.The waveguide design is capable of pro...We propose a polarization-insensitive design of a hybrid plasmonic waveguide(HPWG)optimized at the 3.392µm wavelength which corresponds to the absorption line of methane gas.The waveguide design is capable of providing high mode sensitivity(Smode)and evanescent field ratio(EFR)for both transverse electric(TE)and transverse magnetic(TM)hybrid modes.The modal analysis of the waveguide is performed via 2-dimension(2D)and 3-dimension(3D)finite element methods(FEMs).At optimized waveguide parameters,Smode and EFR of 0.94 and 0.704,can be obtained for the TE hybrid mode,respectively,whereas the TM hybrid mode can offer Smode and EFR of 0.86 and 0.67,respectively.The TE and TM hybrid modes power dissipation of~3 dB can be obtained for a 20-µm-long hybrid plasmonic waveguide at the 60%gas concentration.We believe that the highly sensitive waveguide scheme proposed in this work overcomes the limitation of the polarization controlled light and can be utilized in gas sensing applications.展开更多
Surface stabilized （anti） ferroelectric liquid crystal cells can be used as an optically addressed media for optical data processing. The structure of the cell has to contain a photo sensible agent, i.e, an absorbin...Surface stabilized （anti） ferroelectric liquid crystal cells can be used as an optically addressed media for optical data processing. The structure of the cell has to contain a photo sensible agent, i.e, an absorbing dye-doped orienting layer. The all-optical generation of the diffractive grating can be done due to the switching parameters of the smectic slab within cells with a sensitive layer. This Letter considers a study of the optically induced charge generation into the dye-doped layer, and the explanation of the phenomena of the selective molecular director reorientation, while cell driving what leads to the induction of phase grating.展开更多
基金financially supported by the Russian Foundation for Basic Research(grant No.18-29-20045)for WDM,MDM and hybrid WDM-MDM,WDM-PDM sectionsthe Russian Science Foundation(grant No.21-79-20075)for PDM,OAMM and hybrid PDM-MDM sectionsthe Ministry of Science and Higher Education of the Russian Federation under the FSRC"Crystallography and Photonics"of the Russian Academy of Sciences(the state task No.007-GZ/Ch3363/26)for comparative analysis.
文摘Herein,an attention-grabbing and up-to-date review related to major multiplexing techniques is presented which in-cludes wavelength division multiplexing(WDM),polarization division multiplexing(PDM),space division multiplexing(SDM),mode division multiplexing(MDM)and orbital angular momentum multiplexing(OAMM).Multiplexing is a mech-anism by which multiple signals are combined into a shared channel used to showcase the maximum capacity of the op-tical links.However,it is critical to develop hybrid multiplexing methods to allow enhanced channel numbers.In this re-view,we have also included hybrid multiplexing techniques such as WDM-PDM,WDM-MDM and PDM-MDM.It is prob-able to attain N×M channels by utilizing N wavelengths and M guided-modes by simply utilizing hybrid WDM-MDM(de)multiplexers.To the best of our knowledge,this review paper is one of its kind which has highlighted the most prom-inent and recent signs of progress in multiplexing techniques in one place.
文摘Dielectric resonators are key components in many microwave and millimetre wave circuits and applications, including high-Q filters and frequency-determining elements for precision frequency synthesis. Multilayered and bulk low-loss single crystal and polycrystalline dielectric structures have become very important for designing these devices. Proper design requires careful electromagnetic characterisation of low-loss material properties. This includes exact simulation with precision numerical software and precise measurements of resonant modes. For example, we have developed the Whispering Gallery mode technique, which has now become the standard for characterizing low-loss structures. This paper will review some of the common characterisation techniques used in the microwave to millimetre wave frequency regime.
基金supported by the National Natural Science Foundation of China (No.60676028)the Major State Basic Research Development Program of China (No. 2007CB307003)
文摘An integrated optical chip for fiber optical gyroscope(FOG) is designed and fabricated on GaAs.To achieve a high modulation efficiency and a small chip size,a deeply etched waveguide structure is employed,and accordingly a multimode interference(MMI) coupler is used as the 1 × 2 power splitter.The size of the chip is about 8.5 mm × 0.5 mm,which is much smaller than that of LiNbO3-based chips.The experimental results show that the extinction ratio(ER) of the TE mode to the TM mode is over 26 dB and the value of Vπ·L of the phase modulators is 18 V·cm.The method to further lower Vπ is discussed.
基金supported by the High Efficacy Energy-Saving Project of Zhejiang Province China(No.2006C11007).
文摘An LED driving circuit in accurate proportional current sampling mode is designed and fabricated based on CSMC 0.5 μm standard CMOS technology. It realizes accurate sensing of sampling current variation with output driving current. A better constant output current characteristic is achieved by using an amplifier to clamp the drain voltage of both the sampling MOSFET and power MOSFET to the same value with feedback control. Small signal equivalent circuit analysis shows that the small signal output resistance in the accurate proportional current sampling mode circuit is much larger than that in a traditional proportional current sampling mode circuit, and circuit stability could be assured. Circuit simulation and chip testing results show that when the LED driving current is 350 mA and the power supply is 6 V with ± 10% variation, the stability of the output constant current of the accurate proportional current sampling mode LED driving IC will show 41% improvement over that of a traditional proportional current sampling mode LED driving IC.
基金Project supported by Ministry of Science and Higher Education (N N515 518538)
文摘Luminescent properties of Y2O3 and LaAlO3 nanopowders doped with Pr^3＋ ions and PMMA-based composite materials doped with these powders were reported. The set of active nanopowders differing in praseodymium ions concentration was prepared using sol-gel method and carefully characterized with respect to emission properties in the visible spectral range. In particular, the excitation and emission spectra were measured together with fluorescence decay profiles and the differences between optical properties of these materials were discussed and compared with data available for bulk materials. Finally, the PMMA-based composite materials doped with Pr^3＋：Y2O3 and Pr^3＋：LaAlO3 nanopowders were manufactured and characterized. The obtained results showed that polymer composites doped with active nanopowders in general tended to keep the luminescent properties of the original nanopowders.
基金the financial support from the National Natural Science Foundation of China(Grant No.61875034)the 111 Project(Grant No.B14039)Seeding Project of Scientific and Technical Innovation of Sichuan Province(Grant No.2020107).
文摘Fiber optofluidic laser(FOFL)integrates optical fiber microcavity and microfluidic channel and provides many unique advantages for sensing applications.FOFLs not only inherit the advantages of lasers such as high sensitivity,high signal-to-noise ratio,and narrow linewidth,but also hold the unique features of optical fiber,including ease of integration,high repeatability,and low cost.With the development of new fiber structures and fabrication technologies,FOFLs become an important branch of optical fiber sensors,especially for application in biochemical detection.In this paper,the recent progress on FOFL is reviewed.We focuse mainly on the optical fiber resonators,gain medium,and the emerging sen sing applicatio ns.The prospects for FOFL are also discussed.We believe that the FOFL sensor provides a promising technology for biomedical analysis and environmental monitoring.
文摘In this Letter,a method for shape visualization of small objects(microscopic)in the form of a hologram is presented.It consists of a standard optical set-up for small object registration(i.e.,stereoscopic or biological microscope).The focus stacking technique is used to obtain a series of images with increased depth of field and on them a shape reconstruction procedure(structure from motion,SfM)is made.With use of a dense cloud of points,a sequence of parallax-related images suitable for Geola’s digital holographic printing is generated.The holographic printer produces single-parallax holographic(full three-dimensional)images of real or virtual objects.
基金supported by the National Natural Science Foundation of China(No.61076075)the Natural Science Foundation of Zhejiang Province(No.Y1100287)
文摘A CMOS compatible P＋/Nwell/Psub double junction photodiode pixel was proposed, which can effi- ciently detect fluorescence from CsI（T1） scintillation in an X-ray sensor. Photoelectric and spectral responses of P＋/Nwell, NweE1/Psub and P＋/Nwell/Psub photodiodes were analyzed and modeled. Simulation results show P＋/Nweu/Psub photodiode has larger photocurrent than P＋/Nwetl photodiode and Nweu/Psub photodiode, and its spectral response is more in accordance with CsI（T1） fluorescence spectrum. Improved P＋/Nweu/Psub photodiode detecting CsI（T1） fluorescence was designed in CSMC 0.5 #m CMOS process, CTIA （capacitive transimpedance amplifier） architecture was used to readout photocurrent signal. CMOS X-ray sensor IC prototype contains 8 × 8 pixel array and pixel pitch is 100 × 100 μm2. Testing results show the dark current of the improved P＋/Nwell/Psub photodiode （6.5 pA） is less than that of P＋/Nwell and P＋/Nwell/Psub photodiodes （13 pA and 11 pA respectively）. The sen- sitivity of P＋/Nwell/Psub photodiode is about 20 pA/lux under white LED. The spectrum response of P＋/Nwell/Psub photodiode ranges from 400 nm to 800 nm with a peak at 532 nm, which is in accordance with the fluorescence spectrum of Csl（T1） in an indirect X-ray sensor. Preliminary testing results show the sensitivity of X-ray sensor IC under Cu target X-ray is about 0.21 V.m^2/W or 5097e-/pixel @ 8.05 keV considering the pixel size, integration time and average energy of X-ray photons.
基金This work was financially supported by the Russian Foundation for Basic Research(Grant No.16-29-09528_ofi_m)for numerical calculationsby the Ministry of Science and Higher Education within the State assignment FSRC《Crystallography and Photonics》RAS(Grant No.007-GZ/Ch3363/26)for theoretical results.
文摘We propose a polarization-insensitive design of a hybrid plasmonic waveguide(HPWG)optimized at the 3.392µm wavelength which corresponds to the absorption line of methane gas.The waveguide design is capable of providing high mode sensitivity(Smode)and evanescent field ratio(EFR)for both transverse electric(TE)and transverse magnetic(TM)hybrid modes.The modal analysis of the waveguide is performed via 2-dimension(2D)and 3-dimension(3D)finite element methods(FEMs).At optimized waveguide parameters,Smode and EFR of 0.94 and 0.704,can be obtained for the TE hybrid mode,respectively,whereas the TM hybrid mode can offer Smode and EFR of 0.86 and 0.67,respectively.The TE and TM hybrid modes power dissipation of~3 dB can be obtained for a 20-µm-long hybrid plasmonic waveguide at the 60%gas concentration.We believe that the highly sensitive waveguide scheme proposed in this work overcomes the limitation of the polarization controlled light and can be utilized in gas sensing applications.
文摘Surface stabilized （anti） ferroelectric liquid crystal cells can be used as an optically addressed media for optical data processing. The structure of the cell has to contain a photo sensible agent, i.e, an absorbing dye-doped orienting layer. The all-optical generation of the diffractive grating can be done due to the switching parameters of the smectic slab within cells with a sensitive layer. This Letter considers a study of the optically induced charge generation into the dye-doped layer, and the explanation of the phenomena of the selective molecular director reorientation, while cell driving what leads to the induction of phase grating.
