A Hybrid Integrated and Low-Cost Multi-Chip Broadband Doherty Power Amplifier Module for 5G Massive MIMO Application

In this paper,a hybrid integrated broadband Doherty power amplifier(DPA)based on a multi-chip module(MCM),whose active devices are fabricated using the gallium nitride(GaN)process and whose passive circuits are fabricated using the gallium arsenide(GaAs)integrated passive device(IPD)process,is proposed for 5G massive multiple-input multiple-output(MIMO)application.An inverted DPA structure with a low-Q output network is proposed to achieve better bandwidth performance,and a single-driver architecture is adopted for a chip with high gain and small area.The proposed DPA has a bandwidth of 4.4-5.0 GHz that can achieve a saturation of more than 45.0 dBm.The gain compression from 37 dBm to saturation power is less than 4 dB,and the average power-added efficiency(PAE)is 36.3%with an 8.5 dB peak-to-average power ratio(PAPR)in 4.5-5.0 GHz.The measured adjacent channel power ratio(ACPR)is better than50 dBc after digital predistortion(DPD),exhibiting satisfactory linearity.

4×112 Gb/s hybrid integrated silicon receiver based on photonic-electronic co-design

A 4×112 Gb/s hybrid-integrated optical receiver is demonstrated based on the silicon-photonic vertical p-i-n photodetector and silicon–germanium transimpedance amplifier.We propose a photonic-electronic co-design technique to optimize both the device-level and system-level performance,based on the end-to-end equivalent circuit model of the receiver.Continuous-time linear equalization and shunt peaking are employed to enhance the frequency response.Experimental results reveal that the optical-to-electrical 3-dB bandwidth of the receiver is 48 GHz.Clear open NRZ eye diagrams at56 Gb/s and PAM-4 eye diagrams at 112 Gb/s are achieved without an equalizer in the oscilloscope.The measured bit error rates for 56 Gb/s in NRZ and 112 Gb/s in PAM-4 reach 1×10^(-12)and 2.4×10^(-4)(KP4-FEC:forward error correction)thresholds under-4 dBm input power,respectively.Furthermore,the proposed receiver boasts a power consumption of approximately2.2 pJ/bit,indicating an energy efficient solution for data center traffic growth.

4 × 20 GHz silica-based AWG hybrid integrated receiver optical sub-assemblies

Both the 4 × 20 GHz coarse wavelength division multiplexing and LAN-WDM receiver optical sub-assemblies（ROSAs） were developed. The ROSA package was hybrid integrated with a planar lightwave circuit arrayed waveguide grating（AWG） with 2% refractive index difference and a four-channel top-illuminated positive-intrinsicnegative photodetector（PD） array. The output waveguides of the AWG were designed in a multimode structure to provide flat-top optical spectra, and their end facet was angle-polished to form a total internal reflection interface to realize vertical coupling with a PD array. The maximum responsivity of ROSA was about 0.4 A/W, and its 3 dB bandwidth of frequency response was up to 20 GHz for each transmission lane. The hybrid integrated ROSA would be a cost-effective and easy-assembling solution for 100 Gb E data center interconnections.

112 Gbit/s transmitter optical subassembly based on hybrid integrated directly modulated lasers

Based on the hybrid integration technology, an ultra-compact and low cost transmitter optical subassembly module is proposed. Four directly modulated lasers are combined with a coarse wavelength division multiplexer operated at the O-band. The bandwidth for all channels is measured to be approximately 3 GHz. The 112 Gb∕s transmission is experimentally demonstrated for a 10 km standard single mode fiber（SSMF）, in which an optical isolator is used for avoiding the back-reflected and scattered light to improve the bit error rate（BER） performance. A low BER and clear eye opening are achieved for 10 km transmission.

Detection of Phaeocystis globosa using sandwich hybridization integrated with nuclease protection assay(NPA-SH)

Phaeocystis globosa Scherffel is one of the common harmful algae species in coastal waters of the southeastern China.In this study,sandwich hybridization integrated with nuclease protection assay(NPA-SH)was used to qualitatively and quantitatively detect P. globosa.Results showed that this method had good applicability and validity in analyzing the samples from laboratory cultures and from fields.The linear regression equation for P.globosa was obtained,and the lowest detection number of cells was 1.8×104 c...

Hybrid material integration in silicon photonic integrated circuits

Hybrid integration ofⅢ-Ⅴand ferroelectric materials is being broadly adopted to enhance functionalities in silicon photonic integrated circuits(PICs).Bonding and transfer printing have been the popular approaches for integration of III–V gain media with silicon PICs.Similar approaches are also being considered for ferroelectrics to enable larger RF modulation bandwidths,higher linearity,lower optical loss integrated optical modulators on chip.In this paper,we review existing integration strategies ofⅢ-Ⅴmaterials and present a route towards hybrid integration of bothⅢ-Ⅴand ferroelectrics on the same chip.We show that adiabatic transformation of the optical mode between hybrid ferroelectric and silicon sections enables efficient transfer of optical modal energies for maximum overlap of the optical mode with the ferroelectric media,similar to approaches adopted to maximize optical overlap with the gain section,thereby reducing lasing thresholds for hybridⅢ-Ⅴintegration with silicon PICs.Preliminary designs are presented to enable a foundry compatible hybrid integration route of diverse functionalities on silicon PICs.

Detection of Prorocentrum donghaiense using sandwich hybridization integrated with nuclease protection assay

Prorocentrum donghaiense is an important harmful algae bloom （HAB） causing creature in China＇s seas, and the conventional visual detection can not cope with long-term monitoring and highthroughput sampling projects. An assay for P. donghaiense with sandwich hybridization integrated with nuclease protection assay （NPA-SH） was established. Tests with mixed samples and spiked field ones confirmed its good specificity and sensitivity. The cell number of P. donghaiense correlated well with the optical density, and the regression equation is y=4× 10^- 6x＋ 0.694 9, in which x is the cell number, and y is the optical density, with r2=0.953 5. These results show that the NPA-SH method has good feasibility in the detection of P. donghaiense. Results of NPA-SH and microscopy are excellent for each sample. The NPA-SH method was a simple way in quantitative detection of P. donghaiense, and the whole process could be finished in about six hours, which provided a new approach in high-throughput sampling and long-term monitoring of P. donghaiense.

Integrated model optocouplers

Utilizing hybrid integration model.the integrated model optocouplers have successfully developed.The design,fabrication and characteristic parameters of the devices are presented.

Hybrid-integrated 200 Gb/s REC-DML array transmitter based on photonic wire bonding technology

An 8-channel hybrid-integrated chip for 200 Gb/s(8×25 Gb/s)signal transmission has been demonstrated.The channels are all within the O-band,and with a spacing of 800 GHz.The core of this chip is a monolithic integrated multi-wavelength laser array of 8 directly-modulated distributed feedback(DFB)lasers.By using the reconstruction equivalent chirp technique,multi-wavelength integration and asymmetric phase shift structures are achieved in the laser array.The output laser beams of the array are combined by a planar light-wave circuit,which is hybrid-integrated with the laser array by photonic wire bonding.Experiment results of this transmitter chip show good single-mode working of each unit laser,with a sidemode suppression ratio above 50 dB,and the modulation bandwidth is above 20 GHz.Clear eye diagrams are obtained in the lasers for 25 Gb/s non-return-to-zero modulation,which implies a total 200 Gb/s transmission rate for the whole chip.

Quantifying Contribution of Recycled Moisture to Precipitation in Temperate Glacier Region,Southeastern Tibetan Plateau,China

Recycled moisture is an important indicator of the renewal capacity of regional water resources.Due to the existence of Yulong Snow Mountain,Lijiang in Yunnan Province,southeast of the Qinghai-Tibet Plateau,China,is the closest ocean glacier area to the equator in Eurasia.Daily precipitation samples were collected from 2017 to 2018 in Lijiang to quantify the effect of sub-cloud evaporation and recycled moisture on precipitation combined with the d-excess model during monsoon and non-monsoon periods.The results indicated that the d-excess values of precipitation fluctuated between–35.6‰and 16.0‰,with an arithmetic mean of 3.5‰.The local meteoric water line(LMWL)wasδD=7.91δ^(18)O+2.50,with a slope slightly lower than the global meteoric water line(GMWL).Subcloud evaporation was higher during the non-monsoon season than during the monsoon season.It tended to peak in March and was primarily influenced by the relative humidity.The source of the water vapour affected the proportion of recycled moisture.According to the results of the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model,the main sources of water vapour in Lijiang area during the monsoon period were the southwest and southeast monsoons.During the non-monsoon period,water vapour was transported by a southwesterly flow.The recycled moisture in Lijiang area between March and October 2017 was 10.62%.Large variations were observed between the monsoon and non-monsoon seasons,with values of 5.48%and 25.65%,respectively.These differences were primarily attributed to variations in the advection of water vapour.The recycled moisture has played a supplementary role in the precipitation of Lijiang area.

Oxygen and hydrogen isotope characteristics of different water bodies in the Burqin River Basin of the Altay Mountains,China

Characterization of the spatial and temporal variability of stable isotopes in surface water is essential for interpreting hydrological processes.In this study,we collected the water samples of river water,groundwater,and reservoir water in the Burqin River Basin of the Altay Mountains,China in 2021,and characterized the oxygen and hydrogen isotope variations in different water bodies via instrumental analytics and modeling.Results showed significant seasonal variations in stable isotope ratios of oxygen and hydrogen(δ18O andδ2H,respectively)and significant differences inδ18O andδ2H among different water bodies.Higherδ18O andδ2H values were mainly found in river water,while groundwater and reservoir water had lower isotope ratios.River water and groundwater showed differentδ18O-δ2H relationships with the local meteoric water line,implying that river water and groundwater are controlled by evaporative enrichment and multi-source recharge processes.The evaporative enrichment experienced by reservoir water was less significant and largely influenced by topography,recharge sources,local moisture cycling,and anthropogenic factors.Higher deuterium excess(d-excess)value of 14.34‰for river water probably represented the isotopic signature of combined contributions from direct precipitation,snow and glacial meltwater,and groundwater recharge.The average annual d-excess values of groundwater(10.60‰)and reservoir water(11.49‰)were similar to the value of global precipitation(10.00‰).The findings contribute to understanding the hydroclimatic information reflected in the month-by-month variations in stable isotopes in different water bodies and provide a reference for the study of hydrological processes and climate change in the Altay Mountains,China.

AN IMPROVED HYBRID BOUNDARY NODE METHOD IN TWO-DIMENSIONAL SOLIDS

The hybrid boundary node method （HBNM） is a promising method for solving boundary value problems with the hybrid displacement variational formulation and shape functions from the moving least squares（MLS） approximation. The main idea is to reduce the dimensionality of the former and keep the meshless advantage of the latter. Following its application in solving potential problems, it is further developed and numerically implemented for 2D solids in this paper. The rigid movement method is employed to solve the hyper-singular integrations. Numerical examples for some 2D solids have been given to show the characteristics. The computation results obtained by the present method are in excellent agreement with the analytical solution. The parameters that influence the performance of this method are studied through numerical examples.

The 8×10 GHz Receiver Optical Subassembly Based on Silica Hybrid Integration Technology for Data Center Interconnection

An 8×10 GHz receiver optical sub-assembly （ROSA） consisting of an 8-channel arrayed waveguide grating （AWG） and an 8-channel PIN photodetector （PD） array is designed and fabricated based on silica hybrid integration technology. Multimode output waveguides in the silica AWG with 2% refractive index difference are used to obtain fiat-top spectra. The output waveguide facet is polished to 45° bevel to change the light propagation direction into the mesa-type PIN PD, which simplifies the packaging process. The experimentM results show that the single channel I dB bandwidth of AWG ranges from 2.12nm to 3.06nm, the ROSA responsivity ranges from 0.097 A/W to 0.158A/W, and the 3dB bandwidth is up to 11 GHz. It is promising to be applied in the eight-lane WDM transmission system in data center interconnection.

Efficiency analysis of numerical integrations for finite element substructure in real-time hybrid simulation

Finite element（FE） is a powerful tool and has been applied by investigators to real-time hybrid simulations（RTHSs）. This study focuses on the computational efficiency, including the computational time and accuracy, of numerical integrations in solving FE numerical substructure in RTHSs. First, sparse matrix storage schemes are adopted to decrease the computational time of FE numerical substructure. In this way, the task execution time（TET） decreases such that the scale of the numerical substructure model increases. Subsequently, several commonly used explicit numerical integration algorithms, including the central difference method（CDM）, the Newmark explicit method, the Chang method and the Gui-λ method, are comprehensively compared to evaluate their computational time in solving FE numerical substructure. CDM is better than the other explicit integration algorithms when the damping matrix is diagonal, while the Gui-λ（λ = 4） method is advantageous when the damping matrix is non-diagonal. Finally, the effect of time delay on the computational accuracy of RTHSs is investigated by simulating structure-foundation systems. Simulation results show that the influences of time delay on the displacement response become obvious with the mass ratio increasing, and delay compensation methods may reduce the relative error of the displacement peak value to less than 5% even under the large time-step and large time delay.

Optical transmitter module with hybrid integration of DFB laser diode and proton-exchanged LiNbO_(3)modulator chip

In this work,a hybrid integrated optical transmitter module was designed and fabricated.A proton-exchanged Mach–Zehnder lithium niobate(LiNbO_(3))modulator chip was chosen to enhance the output extinction ratio.A fiber was used to adjust the rotation of the polarization direction caused by the optical isolator.The whole optical path structure,including the laser chip,lens,fiber,and modulator chip,was simulated to achieve high optical output efficiency.After a series of process improvements,a module with an output extinction ratio of 34 dB and a bandwidth of 20.5 GHz(from 2 GHz)was obtained.The optical output efficiency of the whole module reached approximately 21%.The link performance of the module was also measured.

Stability-constrained Two-stage Robust Optimization for Integrated Hydrogen Hybrid Energy System

In order to cope with the challenges brought by multiple uncertainties to integrated hydrogen hybrid energy systems,a stability-constrained two-stage robust optimization method considering small disturbance stability and characteristics of dynamic response is proposed in this paper.In the first operating stage,the charging/discharging state of the battery and the startstop state of the electrolyzer and fuel cell are determined.Then,power constraints for stabilizing ESSs power output is considered between the first and second stage optimization to improve the small disturbance stability of the robust operation plan.Then,the goal of minimizing the operation cost and determine a robust operation operating plan under the worst case is conducting in the second stage optimization.Through the small-signal model with time-delay effect,the eigenvalue analysis method is used to find the ESSs power range,and the small-signal stability of obtained robust operation plan can be enhanced.Finally,the effectiveness and superiority of the proposed method are proved by comparing with the traditional static robust optimization method.Impacts of uncertain parameters on economy and stability are also investigated in a typical example.

Dynamic response of axially moving Timoshenko beams: integral transform solution

The generalized integral transform technique （GITT） is used to find a semianalytical numerical solution for dynamic response of an axially moving Timoshenko beam with clamped-clamped and simply-supported boundary conditions, respectively. The implementation of GITT approach for analyzing the forced vibration equation eliminates the space variable and leads to systems of second-order ordinary differential equations （ODEs） in time. The MATHEMATICA built-in function, NDSolve, is used to numerically solve the resulting transformed ODE system. The good convergence behavior of the suggested eigenfunction expansions is demonstrated for calculating the transverse deflection and the angle of rotation of the beam cross-section. Moreover, parametric studies are performed to analyze the effects of the axially moving speed, the axial tension, and the amplitude of external distributed force on the vibration amplitude of axially moving Timoshenko beams.

Identifying water vapor sources of precipitation in forest and grassland in the north slope of the Tianshan Mountains,Central Asia

Identifying water vapor sources in the natural vegetation of the Tianshan Mountains is of significant importance for obtaining greater knowledge about the water cycle,forecasting water resource changes,and dealing with the adverse effects of climate change.In this study,we identified water vapor sources of precipitation and evaluated their effects on precipitation stable isotopes in the north slope of the Tianshan Mountains,China.By utilizing the temporal and spatial distributions of precipitation stable isotopes in the forest and grassland regions,Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model,and isotope mass balance model,we obtained the following results.(1)The Eurasia,Black Sea,and Caspian Sea are the major sources of water vapor.(2)The contribution of surface evaporation to precipitation in forests is lower than that in the grasslands(except in spring),while the contribution of plant transpiration to precipitation in forests(5.35%)is higher than that in grasslands(3.79%)in summer.(3)The underlying surface and temperature are the main factors that affect the contribution of recycled water vapor to precipitation;meanwhile,the effects of water vapor sources of precipitation on precipitation stable isotopes are counteracted by other environmental factors.Overall,this work will prove beneficial in quantifying the effect of climate change on local water cycles.

Phosphor-free white light-emitting diodes

The multiple color-matching schemes that could improve the color rendering index for phosphor-free white LEDs are discussed. Then we review a few of the recent research directions for phosphor-free white LEDs, which include the development of monolithic GaN-based white LEDs and hybrid integrated GaN-based and A1GalnP-based white LEDs. These development paths will pave the way toward commercial application of phosphor-free white LEDs in the coming years.

Relationship Between Land Use Changes and the Production of Dust Sources in Kermanshah Province,Iran

Recognizing land use changes(LUC)and evaluating their relationship with producing dust sources are considered effective to manage the environment.Taking Kermanshah Province,Iran as study area,dusty days from 2008 to 2015 were selected and dust sources were identified applying thermal-infrared dust index(TDI),hybrid single-particle lagrangian integrated trajectory(HYSPLIT),false color composite(FCC)and true color composite(TCC)of MODerate resolution Imaging Spectroradiometer(MODIS)images.Afterwards,the land use change map was produced using Landsat images in 2000 and 2015.Then,the distribution and frequency of the sources in each land-use change class and important dust production areas were specified.Eventually,two non-parametric tests including Chisquare and Kruskal-Wallis were applied to examine the relationship between LUC and dust sources.Results indicated that the distribution of dust sources was not identical in the study area,and the sources were mainly generated in the areas where land-use change had occurred.In fact,different classes of LUC have different contributions to dust production,and the highest contribution refers to the deflation in gentle slope areas and lowlands where the rangeland has been converted into agriculture land.The findings from this study are useful to manage and control dust in the identified sources.