Journals >Electro-Optic Technology Application
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2025
Volume: 40 Issue 1
11 Article(s)
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Influence of Thermal Effects in Passive Q-Switching Cr4+:YAG Crystal on the Properties of Beam Quality and Longitudinal Mode
CHEN Yifu, BAI Zhenxu, ZHANG Yakai, JIN Duo, WANG Yulei, and LYU Zhiwei
Passive Q-switched lasers are widely used in industrial manufacturing, medical treatment, defense and scientific research. However, systematic investigations into the thermal degradation mechanisms of Cr4+:YAG saturable absorbers under high-power pumping conditions remain insufficient. In this work, a side-pumped quasiPassive Q-switched lasers are widely used in industrial manufacturing, medical treatment, defense and scientific research. However, systematic investigations into the thermal degradation mechanisms of Cr4+:YAG saturable absorbers under high-power pumping conditions remain insufficient. In this work, a side-pumped quasi-continuous-wave standing-wave laser oscillator is constructed to elucidate quantitatively the spatiotemporal coupling mechanism between thermally-induced refractive index gradients in Cr4+:YAG crystals and output beam distortion. Experimental results indicate that the direction and intensity of beam distortion are closely correlated with the thermal effect intensity distribution in Cr4+:YAG crystals, causing multi-peak modulation on the trailing edge of the temporal waveform and an increase in the number of resonant longitudinal modes. Moreover, increasing the initial transmittance of the Cr4+: YAG crystals effectively suppresses thermal effects, and using multiple high-transmittance crystals in series can further enhance the repetition rate capacity of passive Q-switched lasers. This research not only refines the thermal dynamic model of saturable absorbers but also establishes a novel thermal management paradigm for high-power passively Q-switched laser design, providing critical guidance for passively Q-switched technology in high-power and superior beam quality laser systems..
Electro-Optic Technology Application
- Publication Date: Apr. 03, 2025
- Vol. 40, Issue 1, 1 (2025)
[in Chinese]
Electro-Optic Technology Application
- Publication Date: Apr. 03, 2025
- Vol. 40, Issue 1, 1 (2025)
Implementation of Optical Fiber Link Detection Based on OFDR
TAN Jingjia, HAN Qiang, DONG Jie, LIU Zhiming, ZHANG Zhihui, and SHENG Liwen
With the rapid development of optical fiber technology, optical fiber networks have been deployed in aerospace, ships, data centers and industrial internet of things. Due to the principle limitations of traditional optical time domain reflectometer (OTDR), it is difficult to achieve high-resolution testing, and its appWith the rapid development of optical fiber technology, optical fiber networks have been deployed in aerospace, ships, data centers and industrial internet of things. Due to the principle limitations of traditional optical time domain reflectometer (OTDR), it is difficult to achieve high-resolution testing, and its application is limited in the above mentioned complex scenarios. Optical frequency domain reflection (OFDR) technology based on Rayleigh scattering can achieve extremely high spatial resolution, high sensing sensitivity and fast testing rate. The products are suitable for testing and troubleshooting of optical devices, optical modules and short-range optical networks, enabling insertion loss, return loss and length measurement across the entire range from the device to the optical link. A set of optical fiber link detection system is designed and implemented based on OFDR principle. The main problems such as polarization fading effect and nonlinear sweep frequency of the laser are studied. And the spatial resolution of 20 μm is achieved on 112 meters of the testing link..
Electro-Optic Technology Application
- Publication Date: Apr. 03, 2025
- Vol. 40, Issue 1, 7 (2025)
Effect of Time Delay Error between Phase and Amplitude on Coherent Pulse Stacking
LIU Bida, HUANG Zhimeng, ZHOU Dandan, XIA Handing, ZHANG Fan, and PENG Zhitao
A three-pulse time-domain coherent combining system based on the Gires-Tournois interferometer (GTI) cavity is constructed, and the effect of time delay error between phase presetting of pulse burst and amplitude waveform on the combination effect is experimentally studied. When the optical cavity phase control system A three-pulse time-domain coherent combining system based on the Gires-Tournois interferometer (GTI) cavity is constructed, and the effect of time delay error between phase presetting of pulse burst and amplitude waveform on the combination effect is experimentally studied. When the optical cavity phase control system is in closed-loop state, within the range of 1 ns, changing the clock of the pulse phase presetting voltage with an accuracy of 0.1 ns, the evolution process and laws of the coherent stacking waveform is observed and analyzed. The results show that the clock precise synchronization of the phase and amplitude waveforms of the pulse burst can significantly improve the peak value of the coherent stacked waveform. After experimental optimization, three pulse time-domain coherent combination is achieved, and the ratio of main and secondary pulses achieves 6.43∶1. In addition, if there is a time delay between the phase presetting signal and the amplitude waveform, the stacked waveform will be distorted, and the peak value of the main pulse will decrease relative to the synchronized time..
Electro-Optic Technology Application
- Publication Date: Apr. 03, 2025
- Vol. 40, Issue 1, 12 (2025)
Design and Implementation of Integrated System of Spot Positioning and Communication Based on QD
FAN Xinkun, TONG Junyu, and ZHANG Lei
In order to simplify the laser communication system, reduce the system volume and the transmission power consumption, a set of spot positioning and data communication integrated system is designed by avalanche photo diode (APD) type four-quadrant detector. The basic principles are introduced, and the hardware design anIn order to simplify the laser communication system, reduce the system volume and the transmission power consumption, a set of spot positioning and data communication integrated system is designed by avalanche photo diode (APD) type four-quadrant detector. The basic principles are introduced, and the hardware design analysis of the key technologies is carried out. The testing platform is built in the laboratory, and the spot positioning accuracy and communication performance are tested respectively. Testing results show that the spot positioning accuracy can reach 1.2 μm and the communication rate is 20 Mbps, which verifies the feasibility of the designed communication system..
Electro-Optic Technology Application
- Publication Date: Apr. 03, 2025
- Vol. 40, Issue 1, 17 (2025)
Research on Highly Sensitive Pressure Sensing Technology Based on Optical Fiber F-P Cavity
ZHAO Heping, and PENG Peng
A highly sensitive micro-pressure sensor based on Fabry-Prot interferometer (FPI) is proposed. A miniaturized, highly sensitive and accurate optical fiber micro-pressure sensor is developed by establishing a structural model of Fabry-Prot (F-P) cavity end-face coating, and its response characteristics are experimentallA highly sensitive micro-pressure sensor based on Fabry-Pérot interferometer (FPI) is proposed. A miniaturized, highly sensitive and accurate optical fiber micro-pressure sensor is developed by establishing a structural model of Fabry-Pérot (F-P) cavity end-face coating, and its response characteristics are experimentally studied. Experimental results show that the sensor has a sensitivity of -3 854.25 nm/MPa, a measurement range of 0.008 MPa, a linearity of 0.997, a free spectral range of 33.03 nm and an F-P cavity length of 36.32 nm. The proposed sensor is compact, simple and low cost, which has a high sensitivity and a good pressure response characteristic..
Electro-Optic Technology Application
- Publication Date: Apr. 03, 2025
- Vol. 40, Issue 1, 21 (2025)
Preparation of Cerium-rare Earth Polishing Solution for SJ5-2 Optical Lens Polishing
LU Hongyan, ZHANG Mingxuan, HUA Xianli, DU Yujie, and ZHOU Pengyang
SJ5-2 is a new class F optical material developed for developing bifocal lenses. This material is soft, chemically unstable, difficult to solve surface defects during polishing, and the surface profile accuracy is unstable. By analyzing the influence factors of polishing solution on polishing performances, a unique cerSJ5-2 is a new class F optical material developed for developing bifocal lenses. This material is soft, chemically unstable, difficult to solve surface defects during polishing, and the surface profile accuracy is unstable. By analyzing the influence factors of polishing solution on polishing performances, a unique cerium-rare earth polishing solution suitable for SJ5-2 optical lens polishing is determined after a long time of material proportioning testing. For soft material polishing, both polishing efficiency and surface quality should be considered. The particle size of polishing abrasive is larger than 0.34 μm and smaller than 4 μm. In order to maintain a good polishing efficiency, polishing solution should be prepared into a weak acid, and with the production, to be adjusted at any time. The problem of surface defects and unstable surface profile precision can be solved by adding additives suitable for materials with low hardness and poor chemical stability. Compared with the traditional polishing solution, this method can achieve higher material removal amount and improve the quality of the polished surface. This scheme can be extended to other F-class optical glass processing..
Electro-Optic Technology Application
- Publication Date: Apr. 03, 2025
- Vol. 40, Issue 1, 27 (2025)
Research on Accurate Measurement of Surface Displacement in Shield Tunneling Based on Binocular Vision
LI Chunyan, HUANG Zhe, ZHANG Lanqing, and LIU Chengshuo
Aiming at the problems of time, manpower, high cost and low precision of the existing surface displacement monitoring equipment in shield construction, an accurate measurement method of surface displacement based on binocular vision is proposed. The binocular vision measurement technology is used to calculate the threeAiming at the problems of time, manpower, high cost and low precision of the existing surface displacement monitoring equipment in shield construction, an accurate measurement method of surface displacement based on binocular vision is proposed. The binocular vision measurement technology is used to calculate the three-dimensional coordinates of space points, the displacement measurement algorithm is used to calculate the displacement of coordinate points, which realizes the accurate measurement of surface displacement in the process of shield construction. Experimental results show that the repeatability accuracy of x coordinate is better than 0.3 mm, y coordinate is better than 0.1 mm, z coordinate is better than 3 mm, and the absolute measurement accuracy is better than 1.4 mm. The displacement measurement error of this method is less than 1 mm in the field experiment, which meets the requirement of subway tunnel shield construction..
Electro-Optic Technology Application
- Publication Date: Apr. 03, 2025
- Vol. 40, Issue 1, 39 (2025)
Implementation of Fine-tracking Control System Based on Optical Inertial Reference Unit
DING Yutong, and CHE Hongpeng
In order to solve the problems of unstable target acquisition, low tracking accuracy, etc., caused by line-of-sight jitter in the electro-optical precise tracking and pointing system on the moving platform, based on the thought of reference-light-based line-of-sight stabilization technology and optical inertial referenIn order to solve the problems of unstable target acquisition, low tracking accuracy, etc., caused by line-of-sight jitter in the electro-optical precise tracking and pointing system on the moving platform, based on the thought of reference-light-based line-of-sight stabilization technology and optical inertial reference unit (OIRU), an improved fine-tracking control loop suitable for the compound-axis control is designed. And the series control of OIRU and the fine-tracking fast-steering mirror is realized. At first, in order to guarantee the realization of excellent fine-tracking control performances at the same time of the line-of-sight jitter compensation, a low-frequency error boost-frequency prediction function is established to satisfy the high frequency control sampling of the fine-tracking loop. And then, the fine-tracking control is realized by applying nonlinear proportional differential (PD) control algorithm based on extended state observer (ESO). At last, simulations are conducted to verify that the nonlinear PD controller can effectively improve the control performances of the fine-tracking system. In addition, the simulations show that the proposed improved fine-tracking control system can track different threat target trajectories accurately and has good anti-disturbance performance..
Electro-Optic Technology Application
- Publication Date: Apr. 03, 2025
- Vol. 40, Issue 1, 47 (2025)
Curvature Temperature Sensor Based on Hollow-core Fiber Splicing Structure
XU Xinyi, ZHOU Rui, LI Rui, LI Fei, and LIU Yinggang
A curvature and temperature sensor based on the fusion of an optical fiber Mach-Zehnder interferometer (MZI) and a Fabry-Prot interferometer (FPI) is designed and fabricated. The structure of the sensor consists of a section of hollow-core fiber (HCF) cascaded at both ends with no-core fiber (NCF), which is fused singlA curvature and temperature sensor based on the fusion of an optical fiber Mach-Zehnder interferometer (MZI) and a Fabry-Pérot interferometer (FPI) is designed and fabricated. The structure of the sensor consists of a section of hollow-core fiber (HCF) cascaded at both ends with no-core fiber (NCF), which is fused single-mode fiber (SMF) at both ends as the optical input and output, respectively. The spectral response characteristics of the sensor to curvature and temperature are investigated experimentally, and the sensitivity of curvature and temperature response can be obtained by detecting the power change and wavelength drift of the interference spectrum. The maximum temperature sensitivity of 64.7 pm/℃ is obtained in the temperature range of 40 ℃~100 ℃. The maximum curvature sensitivity of 27.044 dBm/m-1 is obtained in the curvature range of 0.39~0.68 m-1. This sensor structure has the advantages of high sensitivity, good reproducibility, good stability, simple fabrication and low cost, which has the potential to be applied in the field of sensing..
Electro-Optic Technology Application
- Publication Date: Apr. 03, 2025
- Vol. 40, Issue 1, 58 (2025)
Development and Optimization of Pressure Fitting Device for O-ring Seals and Thin-walled Shells
MENG Fandong, LIU Dongjie, LIU Lu, LI Wozhao, LIU Jiuzhen, and XUE Mei
To solve the problem of compression deformation and gap bite during the assembly of O-ring seals and thin-walled cylindrical shells, a pressure fitting device is designed. This device is used for assembling sealing caps, sealing rings and shells. According to the assembly form of the parts, the mechanical structure desTo solve the problem of compression deformation and gap bite during the assembly of O-ring seals and thin-walled cylindrical shells, a pressure fitting device is designed. This device is used for assembling sealing caps, sealing rings and shells. According to the assembly form of the parts, the mechanical structure design of the pneumatic device is completed and the electrical circuit is built at the same time. And cylinder selection and pressing force calculation are completed through numerical analysis software. A guide groove is designed according to the installing form of the sealing ring to achieve the closure of the rubber ring. Based on waveform springs, the elastic structure design is completed to achieve zero contact between the upper edge of the shell and the end face of the guide groove, and to avoide deformation and damage to the sealing ring during assembly. By calibrating the waveform spring objective function, the pre-installation force is set to improve the qualification rate and achieve device optimization..
Electro-Optic Technology Application
- Publication Date: Apr. 03, 2025
- Vol. 40, Issue 1, 69 (2025)
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