In this paper, a hole-triggered Si avalanche detector (APD) was prepared based on CMOS process. And the breakdown effect model of the hole-triggered avalanche device was established based on the breakdown characteristics of the device at different operating temperatures. Based on the avalanche breakdown model and the breakdown voltage test results, the parameter of breakdown electric field versus temperature (dE/dT) was obtained by fitting the curve. The breakdown voltage and temperature are positive temperature coefficients at 250~320 K. And the device undergoes avalanche breakdown dominated by dV/dT=23.3 mV/K. The value is determined by the width of the multiplication region as well as the carrier collision ionization coefficient. At 50~140 K operating temperature, the breakdown voltage is a negative temperature coefficient and the device undergoes tunnel breakdown with dV/dT=-58.2 mV/K. The value is mainly influenced by both the spatial extension of the electric field in the avalanche region and the peak electric field.

Junction temperature and carrier temperature are widely concerned as significant parameters affecting LED luminous efficiency. The variation rules of electroluminescence (EL) spectrum and carrier temperature with junction temperature of GaN-based blue micro-LED were investigated in this paper. The accurate real-time measurement of junction temperature and EL spectrum of GaN-based blue micro-LED at current densities of 0.04~53.4 A/cm2 were conducted by using the chip design with a built-in integrated sensor unit, and the range of the low-temperature end of the junction temperature measurement was extended to 123 K using the forward voltage method. The results show that the linear slope of junction temperature and forward voltage change due to carrier leakage and series resistance at low temperature. The high-energy slope method was used for EL spectrum to calculate the carrier temperature at different current densities. It is found that the carrier temperature and junction temperature can be approximately fitted by a quadratic equation within the range of junction temperature and current density under study. And the law of the variation of the carrier temperature with junction temperature and current density was analyzed and explained.

Space astronomical detection commonly uses CCD as the main detector. However, the extreme radiation environment can affect CCD performance and, in turn, impact data acquisition. To gain a deeper understanding of the mechanisms impact on data acquisition, in this paper, based on the SRH theory, the defects effects on charge capture and release during transfer was discussed. A transfer model based on the CCD electrode level was established, and the operation principle of defects under different conditions was simulated. The model was used to simulate STP timing, and to discuss the impact of timing on data acquisition in actual use and the method of extracting relevant parameters from STP timing data, as well as the relationship between the parameters. The model assists in understanding the impact of radiation defects on CCD data transfer, simulating STP timing, and utilizing STP timing to acquire CCD defect parameters in actual applications.

In this paper, an infrared thermal detector based on a metamaterials structure is proposed. It achieved the detection of radiation by utilizing the local field enhancement effect of optical metamaterials and the temperature-sensitive properties of pyroelectric materials. A finite element analysis method was utilized to analyze the infrared absorption characteristics and electromagnetic field properties of the metamaterial absorber, as well as to analyze the thermal properties of the coupled structure of the metamaterial absorber with a pyroelectric material (LiTaO3). The results show that the designed metamaterial absorber can modulate the peak wavelength in the range of 3 to 15 μm (mainly covering the atmospheric window (8~14 μm)), with an absorbance rate of 99.9% and a bandwidth of 0.2 to 1 μm. When the detector size is 23 μm×23 μm, the steady-state temperature increase of the detector is 0.311 K, which is about 21 times higher compared to similar studies. Improved infrared heat detector has significant temperature response, and it is applicable to thermal imaging and sensing in uncooled mid-infrared and far-infrared wavelengths at the large-scale image element level.

A 90° optical hybrid based on an InP 4×4 multimode interference waveguide (MMI) was designed and fabricated. The optical hybrid was fabricated with InGaAsP waveguide layer, InP cladding layer and InP substrate. The width of the single mode waveguide was set to be 2.6 μm, and the length and width of MMI were set to be 844 and 20 μm, respectively. Three dimensional beam propagation method (3D BPM) was used to simulate and analyze the process error tolerance of refractive index, thickness, width and length of wavwguide materials. It is found that optical hybrid’s insertion loss is less than 1 dB and phase deviation is less than 5° in the wavelength range of 1 535~1 565 nm, which is consistent with the simulation result.

In order to improve the output accuracy of fiber optic gyroscope, the BP neural network model optimized by the beetle antennae search algorithm (BAS) was used as the base learner, and the Bagging parallel integrated learning algorithm was used to establish a BAS-BP-Bagging temperature compensation model, and a temperature compensation experiment was conducted for a certain model of fiber optic gyroscope. The experimental results show that under the temperature change environment from -40 ℃ to +60 ℃, the temperature drift of the fiber optic gyroscope after compensation is reduced by nearly 80% compared with that before compensation, 55% compared with the polynomial compensation algorithm, and about 30% compared with the BP neural network compensation algorithm. And the model shows superior generalization performance in the compensation of fresh samples.

A CMOS readout IC for five-spectrum-band TDICCD detector was developed to address the digitization and high-speed readout requirements of 3D integrated multispectral TDI-CMOS image sensors and to solve the matching and consistency problems of the overall layout, physical size and I/O interface with the TDICCD detector. A new column single-slope ADC architecture was designed for this readout IC, which used multi-phase ADC clock and supported correlated multiple sampling (CMS), realizing the digitization and high-speed output of TDICCD output signals and effectively improving the dynamic range and noise performance of the TDICCD detector. The tests after tapeout show that the readout IC functions normally, the imaging results of the integrated TDICCD detector is good and the new column ADC works fine. The readout IC outputs 14 bit data with a minimum line readout period of 9.5 μs, and the CMS reduces output noise effectively, realizing the high-precision digital processing and high-speed output of the TDICCD output signal, and meeting the requirements of 3D integrated TDI-CMOS image sensor development.

A passive Q-switched erbium-doped fiber laser based on a saturable absorber of single-walled carbon nanotubes coupled with a Sagnac loop is proposed. The output laser properties of the laser was experimentally investigated. Single-walled carbon nanotube saturable absorbers were created by light deposition with a 75% transmittance. A Q-switched laser was built to modify the resonators Q value based on the single-walled carbon nanotubes saturable absorption properties. When the Sagnac loop filter was placed inside the optical fiber ring cavity, the Q-switched pulses could achieve fine filtering thanks to the filtering effect produced by the Sagnac loop structure. The Q-switched lasers operating threshold is 800 mW. When the pump power is 830 mW, the laser can produce a stable 1 530.4 nm laser output with an output power of 12.3 mW. The repetition frequency is 210.7 kHz, the corresponding pulse period is 4.76 μs, the pulse width is 2.19 μs, and the maximum pulse energy is 58.37 nJ .

Based on Python language, a semiconductor laser diode simulation EDA program with UI interface was written. The program could set the material composition of the active area of the semiconductor laser diode chip, analyze the material parameters and calculate the waveguide refractive index, draw the refractive index distribution curve and the light intensity distribution curve, calculate the energy band structure and gain characteristics of the active area of the chip, and draw the optical gain spectrum curve under different carrier concentrations. Using the EDA program, the semiconductor laser diode chip with 791 nm wavelength was simulated. The chip with light-emitting region width of 190 μm and cavity length of 4 mm was fabricated and it has a peak power of 16.25 W at 15 A current.

A Ge-based phototransistor with programmable characteristics based on the memristor structure was designed and prepared, which consisted of two back-to-back memristors structured with Ni/Ge/GeOx/Al2O3∶HfO2/Pd, sharing the same resistance switch layer GeOx/Al2O3∶HfO2, substrate Ge and bottom electrode Ni. The design of the resistance switch layer was the key to realize the function of phototransistor. The two top electrodes Pd were used as the source-drain electrodes of the phototransistor, and the area between the two memristors was used as the gate of the phototransistor to receive regulation from external illuminant. The electrical and optical response characteristics of a single Ge-based memristor were explored. The output and transfer characteristics of the phototransistor based on gate-control from illuminant were realized. Furthermore, the scientificity and feasibility of this design was verified through exploring the device physics and mechanism. The phototransistor has advantages of non-volatility and compatibility with standard CMOS process, which can effectively simplify the process and reduce fabrication cost. This phototransistor can provide reference for the next-generation of optoelectronic chip to some extent.

A highly efficient exciplex with significant thermally activated delayed fluorescence characteristics was realized by combining the electron donor of mTPA-PPI and the electron acceptor of PO-T2T. The exciton dynamics processes, such as the reverse intersystem crossing (RISC), prompt fluorescence, and delayed fluorescence of mTPA-PPI∶PO-T2T were explored through the time-resolved spectra technology. A high-performance phosphorescent OLED based on the mTPA-PPI∶PO-T2T co-host was developed. Due to an efficient reverse intersystem crossing process, the triplet exciton utilization was improved, effectively boosting device efficiency and alleviating efficiency roll-off at high current densities. The maximum current efficiency, power efficiency, and external quantum efficiency of the red phosphorescent device based on the co-host are 20.3 cd/A, 18.6 lm/W, and 11.54%, respectively, which were 1.4, 1.2, and 1.5 times that of single-host device. In addition, the maximum luminescence of the co-host device reaches 25 410 cd/m2, which is 3.9 times that of the maximum luminescence of a single-host device.

Electron-only devices with different structures were prepared by doping Liq (8-hydroxyquinolinato-lithium) into the electron transport layer Alq (tris(8-hydroxyquinolinato) aluminum). The experimental results show that the electrical properties of doped devices are inferior to those of non-doped devices with Liq/Al composite cathodes and superior to those of non-doped devices with Al only cathodes. This indicates that Liq’s doped with Alq does not show any significant “n-doping” effect. The effect exhibits dual roles: Liq molecules dispersed at the Alq/Al cathode interfaces after doping display as electron injection layers, which enhances the device currents by enhancing electron injection; those in the bulk of Alq after doping have a detrimental effect on electron transport due to their own poor conductivity, consequently decrease the device currents. In the tests of electroluminescent devices, the doping of Liq shows a similar behavior. The performance of Liq-doped device is between the non-doped devices with Liq/Al cathode and Al cathode structures, with maximum current efficiencies of 3.96, 4.27 and 2.27 cd/A for the three devices, respectively, and no additional changes caused by charge transfer are observed in the absorption and photoluminescent spectra.

Three-parameter Weibull distribution has obvious advantages in fitting the life of LED lamps, but it is not easy to obtain more accurate point estimations of three-parameter Weibull distribution. At present, the commonly used parameter estimation methods, such as maximum likelihood method, moment estimation method, Bayes estimation method, etc., have complex equations, which makes the software programming very troublesome and difficult to master, and the parameter estimations may not be obtained. In view of this, a simple method to estimate the parameters of three-parameter Weibull distribution is proposed for the constant stress accelerated test in this paper. This method did not involve the solution of transcendental equation so that the software programming was quite simple, and the statistical idea was clear. The application of the method was illustrated by several case data of LED lamps under constant stress accelerated test, and the comparative analysis was made with the existing methods.

As has a small diffusion coefficient in HgCdTe material and can form a relatively stable structure, which is widely used in p-type doping of HgCdTe. As doping is an important method in the preparation of p-on-n type HgCdTe infrared detector. In view of the problem that the As activation rate cannot be accurately measured, a low temperature weak p-type annealing assisted hall test method is proposed to obtain the carrier concentration distribution. By comparing with the SIMS test results, the As activation rates in the long and medium wave liquid phase epitaxy HgCdTe material were obtained, and the influence of annealing and other processes on the activation rate after As doping was analyzed.

Polycrystalline gallium nitride (GaN) thin films were deposited at low temperatures on GaAs (001) substrates via plasma-enhanced atomic layer deposition (PEALD). The growth process, surface mechanism and interface characteristics were investigated. The results show that the PEALD temperature window is 215~270 ℃, and the average growth rate of GaN thin films is 0.082 nm/cycle. The GPC analysis was performed in terms of kinetic energy barriers and thermodynamics. It is found that the GaN thin films are polycrystalline with hexagonal wurtzite structure and have a tendency to form (103) crystal. An amorphous layer of about 1 nm is observed at the GaN/GaAs interface, which may be related to limited active sites on the substrate surface before growth and the steric hindrance effect of the precursor. Most interestingly, in the deposited GaN films, all N elements combine with Ga elements to form GaN by Ga-N bonds, but a small part of Ga forms Ga-Ga bonds and Ga-O bonds. This bonding method during deposition may be related to the defects and impurities in the GaN thin films.

The Ag-based films have highest reflectivity from VIS to IR. However, the environmental stability of Ag thin films is poor and susceptible to corrosion with reflectivity reduction. Different thickness ratio of Ta2O5-SiO2 nanolaminate films were prepared by ion beam assisted electron beam evaporation (IAD). The effective refractive index and residual stress of the films were calculated. Furthermore, the nanoaminate film with Ta2O5 thickness percentage of 75% was selected, and the nano-amine structured protective layer Ag-based film system and the conventional two-layer structured protective layer Ag-based film system were further designed and prepared. Multi-band high reflectivity targets were achieved and the residual stress of the two Ag-based films were similar. After 24 hours of humidity test, the reflectance redshift of nanolaminate protection Ag-based films is less than conventional two-layers type protection Ag-based films. After 144 hours of humidity test, the degree of corrosion of the surface defects of nanolaminate protection Ag-based films is less than that of the conventional two-layers type protection Ag-based films. Combined with TEM observation results after combining FIB sample preparation, it is shown that the nanolaminate protection layers possess higher density and can provide better environmental stability for Ag-based films systems.

Using forward and backward finite difference algorithm, the electronic states of InAs/GaSb/AlSb active region structure of antimonide cascade laser were calculated and analyzed theoretically in this paper. The effects of Hamiltonian operator order, effective mass parameter modification, internal interface state on the energy state and wave function were studied. The analyses show that the positive value of the effective mass parameter of the conduction band can effectively inhibit the generation of spurious solutions under two operator orders, and the transition energy under Burt-Foreman operator order is more reasonable. For the internal interface with the slow-change assumption, the calculated value of the transition energy is slightly higher than that of the steep interface, and the wave function profiles of the two are similar near the interface.

WO3 nanorods array films coated with SnO2 nanoparticles were prepared by hydrothermal method and electrochemical deposition method, and WO3/SnO2 heterojunction composite films were formed after annealing. The optimum preparation conditions were obtained by changing the deposition time of SnO2. The phase and morphology of WO3/SnO2 composite film were analyzed by XRD and FESEM. The photoelectric properties of WO3/SnO2 composite film were studied by electrochemical workstation. The results show that WO3/SnO2 composite film has the minimum impedance when the deposition time is 120 s. And its photocurrent density is 0.46 mA/cm2 at a bias voltage of 0.6 V, showing better photochemical properties than a single WO3 nanorod film.

When measuring the transient response of MWIR HgCdTe photovoltaic devices, the device presented a special bimodal pulse response phenomenon when the surface position of the device irradiated by the laser spot was far away from the photosensitive surface. It is analyzed that the abnormal double pulse phenomenon was due to the time difference between the drift of minority carriers in the photosensitive region and the diffusion of minority carriers collected laterally outside the photosensitive region. By applying reverse bias to the device, the impulse response changed from bimodal to unimodal with the increase of reverse bias, which verified that the lateral collection of minority carriers was the main reason for the bimodal formation of the device. The minority carrier lifetime of p-region materials was obtained by fitting the second peak. Comparing the minority carrier lifetime obtained from the transient response with that obtained by the theoretical calculation and the photoconductivity decay method of the p-type MWIR HgCdTe material, it is found that the trends of the minority carrier lifetime obtained from the three methods with temperature are basically the same, which indicates that the minority carrier lifetime of MWIR HgCdTe material can be obtained from the transient photoresponse.

Soliton optical combs in microresonators have broad application prospects in coherent optical communication, optical frequency synthesis, lidar, microwave photonics and quantum optics. Efficient prism coupling provides an inevitable technical approach for integrated application and system packaging of soliton frequency combs in crystal microresonators. In this paper, a MgF2 microresonator-prism coupling system with the coupling efficiency of 71.56% and loaded Q value of 1.8×109 was developed. Based on this efficient prism coupling system, the generation of MgF2 microresonator soliton frequency comb and the low-phase noise microwave signal of 15.99 GHz were realized. And the phase noise level of beat frequency signal is about -117 dB/Hz@10 kHz. It will promote the practical application and development of low-phase noise micro-photoelectric oscillator.

Shape sensing technology is a new research direction in recent years and has a wide range of application prospects. In this paper, a shape reconstruction method based on strain mode mode and error compensation is proposed. By measuring the strain data of some position points of the object, the modal theory was used to realize the strain-displacement transformation, and then the shape of the object was reconstructed. In this paper, titanium alloy plates with length, width and height of 1 000, 1 000 and 0.5 mm were taken as the research object. The displacement mode and strain mode modes were obtained by ANSYS workbench 18 finite element simulation software. According to the modal similarity of position points in the finite element simulation, the K-means++ clustering algorithm was used to optimize the position of strain measuring points, and the strain deformation was generated by applying 400 N force on the upper surface of the alloy plate. The shape reconstruction error of the proposed algorithm is smaller than that of the conventional uniform distribution algorithm. A Radial Basis Function Neural Network (RBFNN) was used to train the error and reconstructed displacement data set. According to reconstructed displacement prediction error, the fitting error was less than 3.5%.

In order to meet the requirements of performance indexes of φ-OTDR in complex engineering field environment, a high-performance φ-OTDR based on adaptive Kalman filter (AKF) and frequency division multiplexing (FDM) is proposed. On the basis of improving frequency response bandwidth of FDM, AKF is used to estimate and correct the statistical characteristics of phase noise linearly responding to external vibration in real time, effectively suppressing the phase distortion caused by fading and crosstalk noise. The experimental results show that sensor linearity of the system is improved, the background noise of the system is reduced to -83.7 dB2/Hz, and the strain resolution is reduced to 0.28 pε/Hz1/2.

In order to meet the requirements of vehicle photoelectric theodolite on the control precision, stability, weight and volume of the servo control system, relevant research was firstly carried out on the main power supply of the servo control system. As the energy supply unit of the servo control system, the stability of the main power supply determined the stability of the servo control system. Then the tracking precision and tracking frequency of the servo control system were affected. In this paper, the design requirements of the power supply, the main circuit, the maximum pulse width limiting circuit, PWM control circuit, voltage and current detection circuit and voltage feedback control circuit were described. At the same time, the power supply was designed according to this method, and the test results were obtained: the power output is 48 V DC; the output power is 2 400 W; the peak-to-peak value is 310 mV; the weight is 13.8 kg; the volume is 350 mm×200 mm×110 mm.

Spacecraft remainders online detection is affected by insufficient marker data. In this paper, the physical characteristics of remainders generation were studied, a remainders model in spacecraft digital twin systems was established, and a cross-domain adaptive spacecraft remainders detection method with digital twin enhancement was proposed. This method was augmented by digital twins to acquire real-time spacecraft data. It then combined similar structural historical marker data and applied a cross-domain adaptive approach to assist current online reasoning. In addition, a new type of cross-domain adaptive approach model was proposed to better mine prior knowledge from complex tasks through a shared network structure and gating mechanism. The model realizes a combination of cross-domain adaptive techniques and digital twins for more efficient, accurate and real-time prediction. This method can comprehensively detect the remainders states of different components of spacecraft.

When the star sensor is operating in space, it is easy to be interfered by stray light such as sunlight, moonlight and earth-air light. As a result, the overall gray level of the star map taken is increased, the background uniformity is poor, and it is difficult to accurately extract the star coordinates. Aiming at the above problems and combining the existing algorithms, a composite background estimation star map processing algorithm under stray light interference is proposed. First of all, star points had the characteristics of dimensions ranging from 3×3 to 7×7 in diameter after point diffusion imaging, so the corresponding background estimation template was designed. Then, in order to improve the robustness of the algorithm and the utilization rate of local information, a pixel estimation template was designed. The two estimation templates calculate the post-processing data at the same time to achieve threshold segmentation, and then the centroid of star points was calculated. This method can better resist stray light interference and improve the accuracy of star extraction under stray light background.

As for the transmission channel in airborne laser communication, research onto combined transmission effects, including channel attenuation, intensity scintillation, beam-wandering and aero-optics effects in the atmospheric channel, were analyzed. Furthermore, transmission performances onto received beamwidth, link outage probability and bit-error rate were derived. The simulation results show that the received beamwidth is boosted by beam-wandering and aero-optics effects, and the beam size at low altitude condition is larger than the high altitude case due to severe atmospheric turbulence. On the other hand, long-range transmission links need to take into account the beam-wandering effect, which can be suppressed by optimizing transmitted laser beamwidth.

To address the problems of low accuracy and complex computation of AKAZE (accelerated-KAZE) algorithm in image matching, an image matching algorithm based on the combination of Gaussian filtering and AKAZE-LATCH (AKAZE-Learned Arrangements of Three Patch Codes) algorithm is proposed. Firstly, the input image was preprocessed by Gaussian filtering to remove continuous noise such as Gaussian noise, and retain the edge information of the image. Then, efficient binary descriptors were constructed for AKAZE using LATCH algorithm, and corresponding matching pairs were obtained using KNN (K Nearest Neighbors) algorithm. Finally, the method was screened again with USAC (Universal RANSAC) to remove false matches, and the final matching result was obtained. Experimental comparison shows that compared with AKAZE algorithm, the proposed algorithm has higher matching accuracy, good robustness and reliability, and can be used for image matching in most complex scenes.