To address the issue of dynamic variations in optimal modulation voltages and resonant wavelength locking targets among microring modulator array units caused by manufacturing process variations, this paper proposes a high-speed signal modulation voltage adaptive wavelength locking technique. By analyzing the impact of high-speed modulation voltages on the microring's average optical power versus wavelength characteristics, we establish the mapping relationship between single/double-peak features and voltage levels. A feedback control system based on STM32 is designed to dynamically determine locking targets（minima for double-peak cases, pre-calibrated reference points for single-peak cases）, employing a step-voltage scanning optimization algorithm for rapid convergence. Simulations and experiments demonstrate that this technique can adapt to modulation voltages ranging from 1~6 Vpp, achieving stable resonant wavelength locking across a 2 nm tuning range with 63 ms locking time and significantly improved eye diagram opening, making it suitable for large-scale array integration.

To meet the urgent demand for high-speed interconnects in data centers driven by the explosive growth of artificial intelligence（AI）computing power, an 800 Gb/s 2×FR4 silicon photonic module technical solution is proposed. This paper introduces the constituent units of the optical module, which employs an integrated multiplexer（MUX）silicon photonic modulator chip, a silicon nitride waveguide cascaded Mach-Zehnder interferometer（MZI）multiplexing structure, and traveling-wave electrode design to achieve efficient modulation and multiplexing of 8×100 Gb/s 4-level pulse amplitude modulation（PAM4）signals. Test results demonstrate that the silicon photonic chip exhibits a 3 dB bandwidth exceeding 30 GHz and an insertion loss ranging from-9 to-12 dB, with all module performance metrics meeting protocol specifications and demonstrating excellent performance.

To address the issue of output wavelength drift in distributed feedback（DFB）semiconductor lasers caused by unstable temperature control circuits, a temperature control system for semiconductor lasers based on sliding mode control is designed. The system employs curve fitting to derive the transfer function of the thermoelectric cooler（TEC）inside the DFB semiconductor laser. A temperature simulation model was constructed in Simulink by incorporating white noise, and the feasibility of proportional-integral-derivative（PID）control, incremental PID control, and sliding mode control is compared. Finally, the temperature control waveforms under different algorithms are compared in the experimental circuit. The experimental results show that by optimizing the design of the sliding mode control system, the response speed and steady-state accuracy of the laser system can be effectively improved. After prolonged testing, the temperature error within a continuous 120-minute period is less than or equal to 0.16%.

To enhance the sensitivity of fiber Fabry-Perot（F-P）cavity acoustic sensors, a novel racket-shaped cantilever fiber F-P cavity acoustic sensor was designed. First, modal analysis and dimensional optimization of the cantilever were performed using COMSOL simulation software. Subsequently, a racket-shaped cantilever fiber F-P cavity acoustic sensor made of 304 stainless steel was fabricated via laser processing technology, with its machining accuracy verified through microscopic measurements. Finally, an acoustic testing system was established to evaluate the sensor's performance across a frequency range of 20~3 000 Hz. Experimental results demonstrate that the sensor exhibits a resonant frequency of 1 750 Hz, with sensitivity exceeding 350 mV/Pa over the 400~3 000 Hz range. At the operational frequency of 1 400 Hz, the sensitivity reaches 3 619.57 mV/Pa under acoustic pressures of 0.01~0.17 Pa, with a linearity of 0.999 8, a signal-to-noise ratio（SNR）of 49.1 dB, and a minimum detectable pres sure（MDP）of 15.03 Pa/Hz1/2.

To optimize the doping process and enhance the performance of 980 nm wavelength GaAs-based semiconductor laser, this paper explores the Zn diffusion technology using solid Zn compound thin films as the diffusion source. The ZnO diffusion source and SiO2 capping layer are fabricated through vacuum coating and plasma-enhanced chemical vapor deposition（PECVD）techniques. Different annealing conditions are combined to regulate the diffusion behavior of Zn in GaAs and InGaAs/GaAs/GaAsP heterostructures. Multiple testing methods are employed to analyze the diffusion rules and their impact on device perfor-mance.The research indicates that the diffusion depth of Zn increases with the rise of annealing temperature and time. The impurity concentration reaches the order of approximately 1020cm-3, and the ratio of the longitudinal diffusion depth to the lateral diffusion depth is 1∶1. Moreover, the diffusion behavior of Zn impurities in the multi-layer heterostructure significantly affects the photoluminescence characteristics of the laser and the integrity of the active region.

To achieve high-precision measurements of salinity, temperature, and pressure, a Mach-Zehnder interferometer（TMZI）based fiber-optic conductivity-temperature-depth（CTD）sensor enhanced by the virtual vernier effect is proposed. By optimizing the fiber structure, the sensor overcomes the mechanical fragility issues associated with traditional single-mode fibers and micro/nano fiber couplers. The spectral data is processed using fast Fourier transform（FFT）and inverse fast Fourier transform（IFFT）, and combined with the virtual vernier effect, significantly improving measurement sensitivity. The experimental results indicate that the sensitivity reaches 37.310 nm/‰ and 16.361 nm/‰ within the salinity ranges of 0~5.85‰ and 5.85‰~19.55‰, respectively, the sensitivity of temperature measurement is-27.667 nm/°C within the range of 30.86~41.95℃, and the sensitivity of pressure sensing is 51.087 nm/MPa within the range of 0~4.5 MPa.

To enhance the transmission capacity of fiber-to-the-home（FTTH）systems and address the limitations of traditional triplexers in polarization dependency and multiplexing capability, a silicon nitride（SiN）multimode interference-based triplexer supporting multi-dimensional multiplexing integration was designed. This device employs a Bragg grating-assisted tilted multimode interference coupler structure. By optimizing the width and position of the input/output waveguides, the tilt angle, and the parameters of the segmented gratings, multiplexing and demultiplexing of eighteen channels are achieved, corresponds to three wavelengths（1 310 nm, 1 490 nm, 1 550 nm）, dual polarization states, and third-order modes. The simulation results show that the insertion loss of each channel is below 1.05 dB, the crosstalk is better than -12.5 dB, and excellent temperature stability and process tolerance are achieved. The temperature drift rates for the transverse electric（TE）and transverse magnetic（TM）modes are as low as 17 pm/°C and 27 pm/°C, respectively.

To meet the high-speed data transmission requirements of the high-definition multimedia interface（HDMI）2.1 protocol and address the latency issues caused by running disparity（RD）dependency in traditional 16b/18b encoders, a high-speed dual-channel parallel 16b/18b encoder design is proposed. By introducing a fast RD generation module and a dual-channel parallel r edundant architecture, the encoding process is optimized, enabling true parallel encoding. Experimental validation is conducted on the Xilinx Zynq UltraScale+MPSoC field-programmable gate array（FPGA）platform. The results demonstrate that at a 400 MHz clock frequency, the encoder achieves a data transmission rate of 14.4 Gb/s with low resource utilization（Block RAM usage of 62.5%）and a power consumption of only 2.636 W. This design significantly reduces encoding latency while maintaining stable linear delay characteristics.

To mitigate the effects of atmospheric turbulence on optical wave propagation and improve indoor simulation accuracy, this study systematically reviews the theoretical and technological advancements in atmospheric turbulence simulation based on spatial light modulators（SLMs）. First, the phase modulation principle of liquid crystal spatial light modulators（LC-SLMs）is analyzed. Subsequently, turbulence phase screens are generated using Zernike polynomial methods, Fourier transform spectral inversion, and subharmonic compensation techniques to achieve high-precision turbulence simulation. The analysis demonstrates that SLM technology offers significant advantages, including real-time tunability, high modulation accuracy, and compatibility with multi-wavelength environments, making it effective for applications such as optical communication performance evaluation, adaptive optics correction, and imaging quality optimization. Future improvements in liquid crystal device performance, refresh rates, and multi-physics coupling technology are expected to further enhance the realism and practicality of turbulence simulation.

To address the challenge of non-contact signal transmission for high-speed rotating components in aero-engines, a wireless laser communication system for rotating environments was designed. The system employs a vertical-cavity surface-emitting laser（VCSEL）and a PIN photodiode to establish an optical communication link. A field-programmable gate array（FPGA）master control module coordinates the MAX3656 driver chip and MAX3760/MAX3762 amplifier circuits to achieve efficient electrical/optical/electrical signal conversion and processing. Combined with self-developed host computer software, real-time data parsing and display are accomplished. Experimental results demonstrate that the system achieves stable data transmission at 100 Mb/s over a 20 cm distance, with a power consumption of only 3.45 W. No waveform distortion occurs when the input signal frequency is ≤100 MHz, and zero bit errors are observed in host computer data parsing.

To address the issue of reduced measurement accuracy for vortex beam displacement in ocean turbulence, this paper proposes a vortex beam displacement measurement method based on the Gerchberg-Saxton（GS）algorithm. By reconstructing the original phase distribution of the vortex beam from distorted intensity profiles using the GS algorithm and performing cross-correlation matching with a pre-established turbulence channel template library, high-precision displacement localization is achieved. Simulation results show that the performance of this algorithm is inferior to traditional algorithms under no or weak turbulence conditions, but outperforms traditional algorithms under strong turbulence conditions; moreover, the larger the mode value of the Laguerre-Gaussian（LG）beam, the greater the mean square error in measurement.

To address the high-reliability communication requirements between commercial spacecraft modules under extreme vibration conditions, this paper proposes a close-range laser communication system resistant to multi-degree-of-freedom coupled vibrations. By employing a composite optical path compensation structure, a large divergence angle optical system, and a deep learning-based adaptive control algorithm, the system effectively resolves technical challenges such as optical component defor-mation and optical path instability caused by multi-degree-of-freedom vibrations. The experimental results indicate that, even under extreme operating conditions involving a 20° rotation, a communication distance of 200 mm, and a 10 mm offset, the system maintains stable communication performance with a received power fluctuation of less than 2 dBm. Furthermore, under the most severe conditions, where both a 10 mm offset and a 20° rotation coexist at a communication distance of 200 mm, the received power remains stable above -10.84 dBm.

To improve the tracking accuracy of free-space satellite quantum laser communication ground terminals and achieve a lightweight design, a lightweight quantum laser communication tracking system based on dual-detector compound-axis tracking technology is designed. The system adopts a T-shaped aluminum alloy tracking frame and a silicon carbide primary mirror structure, combined with a coarse-fine tracking hierarchical control strategy. Residual errors are compensated by a piezoelectric fast steering mirror, and an intelligent parameter-tuning proportional-integral-derivative（PID）control algorithm is introduced to optimize parameters. Experimental results show that during the satellite-to-ground field test, the standard deviation of coarse tracking accuracy is 4 arcsec（azimuth axis）and 6.3 arcsec（elevation axis）. After fine tracking closed-loop correction, the composite error standard deviation is reduced to 1.4 arcsec（azimuth axis）and 1.2 arcsec（elevation axis）. Meanwhile, the system weight is reduced by 50% compared with traditional designs.

To improve the communication quality and reduce the bit error rate（BER）of tilted multiple-input single-output underwater wireless optical communication（T-MISO-UWOC）systems, a spherical T-MISO-UWOC（ST-MISO-UWOC）system model was proposed. Through theoretical analysis and numerical simulations, the differences between the ST-MISO-UWOC system and the conventional T-MISO-UWOC system in key performance metrics such as BER, received optical power, and Q-factor were investigated. Simulation results show that under a signal-to-noise ratio（SNR）of 20 dB, a transmission distance of 1.5 m, and a data rate of 12 Gb/s, the BER of the ST-MISO-UWOC system is as low as 3.09×10-12, which is five orders of magnitude lower than that of the conventional system（8.08×10-7）. Additionally, the ST-MISO-UWOC system exhibits significantly improved stability in optimal decision timing, higher received optical power, and stronger adaptability in high-speed and long-distance transmissions.

To ensure the stable operation of spaceborne coherent laser communication systems based on polarization optical path under extreme space thermal environments, a thermal control design scheme is proposed. This scheme combines passive and active thermal control technologies. The external heat flux distribution under typical orbital conditions is analyzed through NX/TMG software simulation, leading to the determination of a passive thermal control strategy involving multilayer insulation material wrapping and heat dissipation surface optimization. Additionally, a zoned temperature control active heating system is designed, utilizing a proportional-integral-derivative（PID）algorithm to achieve a temperature control accuracy of ±3℃. Thermal balance test results show that the optimized system maintains polarization purity stably above 95%, with beam divergence angle controlled within 65±5 rad under 22 ±3℃ conditions, significantly enhancing the thermal stability of the optical system and communication reliability.

To enhance the pulse stability and shaping accuracy of fiber laser systems in inertial confinement fusion（ICF）experiments, a precision laser pulse drive system based on a low-noise electrical pulse drive power supply is designed. By integrating ripple suppression circuits and low-dropout linear regulators（LDO）, the system optimizes the noise suppression performance of the electrical pulse drive power supply. Combined with a Mach-Zehnder modulator（MZM）, it achieves highly stable optical pulse output. Experimental results demonstrate that the optimized drive system reduces the electrical pulse ripple amplitude from±20 mV to ±0.5 mV, significantly decreasing optical pulse jitter. When applied to a high-power fiber laser system, the root mean square（RMS）of the output pulse energy decreases from 2.24% to 0.72%, improving stability by 67.8%.

To improve the reception performance of weak quadrature phase-shift keying（QPSK）modulated signals and surpass the standard quantum limit（SQL）, this paper proposes a photon-number-resolving（PNR）quantum-enhanced receiver scheme based on a fiber storage ring. By integrating single-photon detectors（SPDs）with a fiber storage ring structure, the scheme achieves efficient photon-number-resolving capability. Adaptive feedback control and Bayesian probability updates dynamically optimize the displacement operator, significantly reducing system complexity and implementation costs. Simulation results demonstrate that when the average photon number ||2≥1.5, the symbol error rate of this scheme breaks the SQL, showing approximately a 10% reduction compared to traditional SPD schemes. Particularly under weak coherent states（||2<2）, the storage ring structure exhibits higher measurement accuracy and lower error rate.

To improve the measurement accuracy and efficiency of time delay parameters in time-division multiplexed fiber optic detector arrays, a time delay parameter measurement method based on a time-division multiplexed fiber optic detector array is proposed. This method constructs a data matrix to extract variance vectors, performs correlation operations using a pulse template function, identifies the positions of interference pulses, and thereby calculates the time delay parameters. Experiments were conducted on an 8-channel time-division multiplexed array to verify the method's reliability under different signal-to-noise ratio（SNR）conditions. The results show that when the SNR is above 12 dB, the measurement accuracy reaches 100%. When the SNR drops to 7 dB, the success rate remains over 98%. Even at an extremely low SNR of -3 dB, the method maintains a correct rate above 65%.

In response to issues such as high transmission loss, poor amplitude-phase consistency, and weak anti-interference capability in traditional millimeter-wave direction-finding technologies, a high-precision millimeter-wave direction-finding technique based on microwave photonics is proposed. This technology integrates parallel Mach-Zehnder modulator（MZM）coherent photonic frequency conversion with multi-baseline interferometric direction finding algorithms, achieving low-loss transmission and high-fidelity frequency conversion of millimeter-wave signals through optical-domain signal processing. A multi-channel array antenna pattern calibration method is employed to compensate for system amplitude-phase errors, while an approximate interacting multiple model（IMM）direction finding filtering algorithm is utilized to eliminate abnormal direction finding values. Simulations and experimental results demonstrate that this technology reduces the direction finding fluctuation range from 27.2°~32.5° to 29.7°~30.2°, with a maximum mean square error of 0.31°, significantly outperforming conventional microwave direction finding methods.