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Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

【Objective】In this paper, an ultra-low power consumption optical transmitter is developed to broaden the application of optical communication in short-reach interconnection such as board level and backplane level. The basic principle of the scheme is that the Vertical-Cavity Surface-Emitting Laser (VCSEL) laser generates an optical pulse signal after loading a bias current and a modulation signal through a Bias-T circuit.【Methods】In this work, the feasibility of the scheme is verified by means of simulation. It is also found that the main factors affecting the increase of the transmission rate are the parasitic parameters of the laser device and the impedance matching of the drive circuit. The two electrical transmission distances of 200 and 10 mm are studied by experiments. And the law of eye diagram quality and bit error rate as a function of driving voltage and bias current is studied through experiments under two electrical transmission distances.【Results】The results show that a larger effective extinction ratio ranging from 0.84 to 6.69 dB can be obtained by shortening the electrical transmission distance to 10 mm with the minimum differential driving voltage of 200 mV, the minimum bias current of 15 mA, and the power consumption of 1.2 mW/Gbit/s. Compared with traditional optical modules, the power consumption of optical transmission is reduced by about 80%.【Conclusion】This optical transmitter solution can be applied to intra-data center. Combined with low-power optical receivers, the overall power consumption of the data center can be significantly reduced.

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Study on Optical Communications / Guangtongxin Yanjiu is the property of Study on Optical Communications Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Micronanoelectronic Technology is the property of Micronanoelectronic Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To meet the growing demand for communication capacity, new multi-carrier fiber optical communication technology has become the focus of scientific researchers' attention. The paper reviews the development of traditional Orthogonal Frequency Division Multiplexing (OFDM) in the field of fiber optical communication over the past 20 years and summarizes relevant research on Filter Bank Multi Carrier (FBMC) and Universal Filter Multi Carrier (UFMC) in recent years. Since 2016, scholars worldwide have been addressing the drawbacks of OFDM in optical communication, such as high out-of-band leakage, reliance on Cyclic Prefixes (CP), high Peak-to-Average Power Ratio (PAPR) values, and stringent system synchronization requirements. They have initiated research using new multi-carrier systems as a breakthrough point. FBMC optical communication is characterized by minimal sidelobe power and high spectral efficiency, but due to the use of Offset Quadrature Amplitude Modulation (OQAM), the corresponding Digital Signal Processing (DSP) algorithm needs to be redesigned for virtual part interference. UFMC optical communication has a strong tolerance for time synchronization deviation, and it is less sensitive to frequency offsets. Moreover, it can reuse the DSP algorithms of OFDM. However, challenges remain in further suppressing out-of-band power and reducing computational complexity. Finally, based on the current research status, the paper proposes research directions and suggestions for advancing the next-generation fiber optical communication system.

【Objective】The commonly used max-log-map algorithm reduces the complexity of soft information computation compared to the log-map algorithm. However, it still consumes significant resources for high-order Orthogonal Amplitude Modulation (QAM), such as 8QAM, 16QAM Probability Shaping (PS), and 64QAM PS.【Methods】8QAM adopts the method of constellation region division, and the soft information is represented by the distance information from the received symbol to the perpendicular between the nearest bit 0 and bit 1. The distance information is simplified and calculated using angle rotation and regional symmetry. For 16QAM PS and 64QAM PS with non Maxwell Boltzmann (MB) distribution, the central boundary between the edges of the bit 1 region and the central boundary between bit 0 on both sides of the bit 1 region no longer coincide. Region merging approximation is used to handle the region ownership between the two boundaries, and the max-log-map expression is factorized to simplify the distance difference to calculate the soft information. The soft information of 16QAM PS and 64QAM PS based on MB distribution can be obtained by simplifying the soft information expression of non-MB distribution.【Results】The simplification reduced the multiplication and addition/subtraction operations in 8QAM soft information calculation from 48 and 75 times to 12 and 16 times respectively. with a degradation of only about 0.05 dB. For MB-distributed 16QAM PS, operations reduce from 192 multiplications and 260 additions/subtractions to 2 and 4, respectively, also with a degradation of only about 0.05 dB. The reduction is even greater for 64QAM PS, decreasing from 1 152 multiplications and 1 542 additions/subtractions to 3 and 6, respectively.【Conclusion】This article proposes a soft information computation method suitable for 8QAM and MB-distributed 16QAM PS, MB-distributed 64QAM PS, non MB-distributed16QAM PS, and non MB-distributed 64QAM PS. When probabilities align with the MB distribution, the non MB methods can transform into the MB methods. When the shaping factor is 0, the expression based on the MB distribution can be converted into a uniformly distributed soft information calculation formula. The soft information calculation for non-MB distribution, MB distribution, and uniform distribution can be uniformly designed on the same circuit, improving circuit reuse rate and reducing the hardware resource consumption.

Objective The commonly used max-log-map algorithm reduces the complexity of soft information computation compared to the log-map algorithm. However, it still consumes a large number of resources for high-order Orthogonal Amplitude Modulation (QAM), such as 8QAM, 16QAM Probability Shaping (PS), and 64QAM PS. Methods 8QAM adopts the method of constellation region division, and the soft information is represented by the distance information from the received symbol of the perpendicular of the nearest bit 0 and bit 1. The distance information is simplified and calculated using angle rotation and regional symmetry. For 16QAM PS and 64QAM PS distributed by non Maxwell Boltzmann (MB) distribution, the central boundary between the edges of the region where bit 1 is located and the central boundary between bit 0 on both sides of the region bit 1 no longer coincide. The region merging approximation is used to handle the region ownership between the two boundaries, and the max-log-map expression is factorized to simplify the distance difference to calculate the soft information. The oft information of 16QAM PS and 64QAM PS based on MB distribution can be obtained by simplifying the soft information expression of non MB distribution. Results After the above simplification, the multiplication and addition/subtraction times of 8QAM soft information calculation were reduced from 48 and 75 times to 12 and 16 times respectively with a degradation of only about 0.05 dB; The 16QAM PS with MB distribution has 192 multiplication times and 260 addition/subtraction times reduced to 2 and 4 times, respectively, resulting in a degradation of only about 0. 05 dB. Higher order 64QAM PS has a greater reduction in resource consumption reduced the multiplication and addition/subtraction times from 1 152 and 1 542 times to 3 and 6 times, respectively. Conclusion This article proposes a soft information calculation method suitable for 8QAM and MB distribution of 16QAM PS, MB distribution of 64QAM PS, non MB distribution of 16QAM PS, and non MB distribution of 4QAM PS. When the probability satisfies the MB distribution, the soft information calculation method suitable for non MB distribution can be converted into the MB distribution calculation method. When the shaping factor is 0, the expression based on the MB distribution can be converted into a uniformly distributed soft information calculation formula. The soft information calculation for non MB distribution, MB distribution, and uniformly distributed probability can be designed uniformly on the same circuit, improving circuit reuse rate and reducing the hardware resource consumption. [ABSTRACT FROM AUTHOR]

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the explosive growth of global network traffic and the consequent increase in bandwidth and energy consumption required for data transmission, traditional electronic interconnection architectures are no longer able to meet the requirement of the growing bandwidth and energy conservation. Silicon-based photonics featured as high bandwidth, low energy consumption, and more importantly, compatibility with Complementary Metal-Oxide-Semiconductor (CMOS) technologies enables the large-scale Photonic Integrated Circuits (PIC) and Electronic Integrated Circuits (EIC) to be integrated in a single substrate, hence it is regarded as one of the most promising solutions to address these challenges. However, with the increasing frequency of signals and the increasing number of integrated photonics and electronic devices, parasitic effects are becoming more prominent, leading to a significant degradation in the integration density, bandwidth density, and energy efficiency of the chip. 2.5D/3D integration technologies can effectively reduce the electrical interconnect length and chip size, thus reducing parasitic effects and power consumption, as well as increasing integration density. This paper presents different schemes of silicon based optoelectronic integration and its recent advances, and looks forward to the application prospects of 2.5D/3D integration technologies in data communication, Light Detection and Ranging (LiDAR), biochemical sensing, and optical computing, et al.

Optical modules are the basic building blocks of 5G transport networks, data center interconnections and all-optical access networks.With the rapid development of upper-layer service and applications, high-speed optical modules had become the key element to achieve high bandwidth and wide coverage in various application fields.Based on the basic concepts and the overall view of standardization research of optical modules, the technical solutions, standardization status and market development trend of 400 Gbit/s, 800 Gbit/s intensity and phase modulation high-speed optical modules were focused on.Finally, suggestions to promote the healthy development of optical modules in the future were proposed.

With the full deployment of 5th generation mobile communication network, the optical communication industry has entered the stage of comprehensive and rapid development. According to the demand of data center optical module market, the optical module will develop to high speed and low price in the future. The 400 Gbit/s Quad Small Form Factor Pluggable-Double Density (QSFP-DD) studied in this paper is based on the theory of near Gauss Beam. The optical path is designed and simulated by ZEMAX software, and the spherical parameters are optimized by the optimization function. The coupling efficiency is 74.8%, and the coupling efficiency under different offset is analyzed to get the error range. After analyzing the Fresnel reflection of the contact surface, and comparing the performance of the device under different grinding angles and the high-temperature fiber transmission test of the module, an oblique 8 ° for adaptation is selected. According to the requirements of the protocol, the optical design of this paper with 8 ° angle optical fiber can meet the requirements of the use of the scene.

With the full deployment of 5th generation mobile communication network, the optical communication industry has entered the stage of comprehensive and rapid development. According to the demand of data center optical module market, the optical module will develop to high speed and low price in the future. The 400 Gbit/s Quad Small Form Factor Pluggable-Double Density (QSFP-DD) studied in this paper is based on the theory of near Gauss Beam. The optical path is designed and simulated by ZEMAX software, and the spherical parameters are optimized by the optimization function. The coupling efficiency is 74.8%, and the coupling efficiency under different offset is analyzed to get the error range. After analyzing the Fresnel reflection of the contact surface, and comparing the performance of the device under different grinding angles and the high-temperature fiber transmission test of the module, an oblique 8 ° for adaptation is selected. According to the requirements of the protocol, the optical design of this paper with 8 ° angle optical fiber can meet the requirements of the use of the scene.

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the explosive growth of global network traffic and the consequent increase in bandwidth and energy consumption required for data transmission, traditional electronic interconnection architectures are no longer able to meet the requirement of he growing bandwidth and energy conservation. Silicon-based photonics featured as high bandwidth, low energy consumption, and more importantly, compatibility with Complementary Metal-Oxide-Semiconductor (CMOS) technologies enables the large-scale Photonic Integrated Circuits (PIC) and Electronic Integrated Circuits (EIC) to be integrated in a single substrate, hence it s regarded as one of the most promising solutions to address these challenges. However, with the increasing frequency of signals and the increasing number of integrated photonics and electronic devices, parasitic effects are becoming more prominent, eading to a significant degradation in the integration density, bandwidth density, and energy efficiency of the chip. 2.5D/3D integration technologies can effectively reduce the electrical interconnect length and chip size, thus reducing parasitic effects and power consumption, as well as increasing integration density. This paper presents different schemes of silicon based optoelecronic integration and its recent advances, and looks forward to the application prospects of 2.5D/3D integration technologies in data communication, Light Detection and Ranging (LiDAR), biochemical sensing, and optical computing, et al. [ABSTRACT FROM AUTHOR]

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Optical modules are the basic building blocks of 5G transport networks, data center interconnections and all-optical access networks. With the rapid development of upper-layer service and applications, high-speed optical modules had become the key element to achieve high bandwidth and wide coverage in various application fields. Based on the basic concepts and the overall view of standardization research of optical modules, the technical solutions, standardization status and market development trend of 400 Gbit/s, 800 Gbit/s intensity and phase modulation high-speed optical modules were focused on. Finally, suggestions to promote the healthy development of optical modules in the future were proposed. [ABSTRACT FROM AUTHOR]

Silicon-based optoelectronics technology has the advantages of photonics, such as broadband, high-speed and anti-interference, as well as the advantages of microelectronics, such as large-scale integration, low energy consumption and low cost.Silicon-based optoelectronics is showing superior advantages in high-speed and short-reach communications and posing a challenge to the conventional indium phosphide (InP) optical modules.The application, development and technical challenges of silicon-based optoelectronics technology in communications were briefly discussed.There is an urgent need to develop high performance devices, packaging technology, automation software for further development of the silicon-based optoelectronic technology.

With the vigorous development of network technology, optical networks are developing in the direction of ultra-highspeed and large-capacity. Since the structure of the optical network is becoming more complex.the optical signal will inevitably suffer various impairments in the optical network. In optical communication equipment, the most important parameter of the physical layer is the Optical Signal-to-Noise Ratio (OSNR). Its value directly determines whether the service can operate normally. Once the requirements are not met, it will cause transmission errors or failures, reducing service quality, and transmission consumption. This paper proposes an accurate and efficient OSNR prediction method for optical communication nodes. By combining analytic prior knowledge methods and deep learning-based posterior knowledge methods, an optical communication node OSNR based on hybrid machine learning algorithms are proposed. The prediction method uses prior knowledge to reduce the training cost of neural networks and provides high-accuracy OSNR predictions. The result shows that the method proposed in this paper can provide high-accuracy machine learning models under more demanding conditions.

With the vigorous development of network technology, optical networks are developing in the direction of ultra-highspeed and large-capacity. Since the structure of the optical network is becoming more complex.the optical signal will inevitably suffer various impairments in the optical network. In optical communication equipment, the most important parameter of the physical layer is the Optical Signal-to-Noise Ratio (OSNR). Its value directly determines whether the service can operate normally. Once the requirements are not met, it will cause transmission errors or failures, reducing service quality, and transmission consumption. This paper proposes an accurate and efficient OSNR prediction method for optical communication nodes. By combining analytic prior knowledge methods and deep learning-based posterior knowledge methods, an optical communication node OSNR based on hybrid machine learning algorithms are proposed. The prediction method uses prior knowledge to reduce the training cost of neural networks and provides high-accuracy OSNR predictions. The result shows that the method proposed in this paper can provide high-accuracy machine learning models under more demanding conditions.

To improve the accuracy of indoor visible light positioning, the received signal strength indication visible light positioning method based on Levy flight mutation mechanism combined with adaptive movement factor improved golden sine algorithm was adopted. The light-emithing diode lights on the indoor roof were arranged in a 3x3 grid, and the distance d between the unknown node and the reference node was obtained through the Lambertian model after receiving the light intensity signal. The Levy flight mutation mechanism was used to increase the diversity of the algorithm's search space, and the adaptive movement factor is used to increase the algorithm's convergence speed, so that individual updates were less restricted by local extreme values. The simulation shows that the average positioning error of the improved algorithm is 1cm, and the average number of iterations is 40~80. Therefore, the speed and precise positioning of the improved golden sine algorithm are improved, which is helpful for real-time and rapid positioning of large indoor places. [ABSTRACT FROM AUTHOR]

In order to solve the demodulation distortion caused by light intensity disturbance and modulation depth drift in traditional phase generated carrier (PGC) demodulation algorithm, an improved PGC demodulation algorithm based on fundamental wave mixing and differential self multiplication was adopted. And relevant theoretical analysis and simulation verification were carried out. The results show that the distortion caused by light intensity disturbance can be suppressed, and the demodulation efficiency can be improved at the same timeby using this algorithm. When the light intensity disturbance of 1.5rad ~3.5rad was introduced, the signal-to-noise and distortion ratio of nearly 30dB was obtained, which was 15dB higher than the traditional discrete cosine transform (PGC-DCM) algorithm. In addition, the dependence on modulation depth C can be eliminated, and the total harmonic distortion of less than 0.1% and the signal-to-noise ratio of 30dB can be achieved, which was nearly 10dB higher than the traditional algorithm, and the corresponding linearity was up to 99. 99%. It provides a new scheme for the demodulation of optical fiber interferometric sensor. [ABSTRACT FROM AUTHOR]

In order to solve the peak-to-average power ratio (PAPR) problem in the direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) underwater visible light communication system, a joint PAPR suppression algorithm based on Vandermonde-like matrix (VLM) precoding and improved adaptive scaling was adopted. Firstly, the frequency domain signal was preceded by VLM to reduce the autocorrelation of the signal, and then the time domain signal was adaptively scaled to reduce the nonlinear distortion caused by light-emitting diode (LED). Finally, the PAPR suppression effect of the system was realized. The results show that when the complementary commulative distribution function was 10-3, the PAPR of the joint algorithm was reduced by 3. 2dB compared with the original system. Therefore, this research is helpful to suppress the PAPR of DCO-OFDM underwater visible light communication system. [ABSTRACT FROM AUTHOR]

With the demand of data center traffic soaring, many service providers are already working on 400 Gbit/s Ethernet communication systems. Compared with the 100 Gbit/s optical module, the 400 Gbit/s optical module can provide higher transmission bandwidth with lower power consumption and cost. Aiming at the above requirements, this paper proposes a design scheme of 400 Gbit/s optical transceiver module for data center optical communication network system. We first introduce the 400 Gbit/s optical module related protocols and standards. Then we present the general design of the module framework, mainly from the rate of conversion, launch, receive and monitoring 4 parts. Finally, we conduct a performance test and the test results show that the module in accordance with the agreement and the provisions of the standard, which is a good solution to realize data center 400 Gbit/s Ethernet transmission.

In recent decades, with the rapid progress of Information and Communications Technology (ICT), the impact of informatization on the social operation and human life is deepening. Based on the level of digitalization, networking and intelligentization, we review the history of informatization, and propose that the development stage after digital twin will be digital intelligence and digital transcendence. As informatization is becoming the key driving force of network evolution in the future, we put forword 4 characteristics for the future network, namely network-computing collaboration, access collaboration, photoelectric cooperation and network intelligentization, and emphasize the key role and challenge of optical communication.

Copyright of Study on Optical Communications / Guangtongxin Yanjiu is the property of Study on Optical Communications Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As a new high speed underwater wireless communication technology, underwater wireless optical communication (UWOC) plays an important role in marine ecological environment monitoring, resource exploration, and military operations, and has become a key technology for competition all over the world. Three kinds of underwater wireless communication modes were compared, the channel characteristics of UWOC were introduced, and the research progress of key technologies such as light source, modulation, channel coding, and detection in UWOC system were described in detail. At the same time, the development trend of UWOC technology was summarized, which provides a reference for further research and practical application of UWOC system in the future. [ABSTRACT FROM AUTHOR]

For the key technologies and latest research progress on chaotic secure optical communication,chaos generation methods based on different nonlinear components were introduced firstly.Then the research progress of chaotic optical communication was discussed,including how to improve the security level,and how to increase the transmission capacity and distance of chaotic optical communication.At last,the limitations and potentials of chaotic optical communication were discussed,the key technologies and research progress of chaotic secure optical communication were summarized.

The calculation of fog attenuation empirical model is an important method to predict fog attenuation. In order to apply the fog attenuation empirical model to practice for applicability analysis, based on Mie scattering theory, the attenuation of the laser under different visibility in the Kruse model, Kim model and Ijaz model was calculated using theoretical derivation and simulation analysis methods. The diiference between the three models in calculating the attenuation coefficient was analyzed, and the experimental results were compared with the simulation results by building a free-space optical communication experimental platform. The results show that the attenuation results of the 650nm wavelength laser in the fog attenuation channel are closer to the Kim attenuation model. This research conclusion provides a reference for the analysis of the fog attenuation coefficient of the free space optical communication system in Xi'an. [ABSTRACT FROM AUTHOR]

In order to study the effect of aperture reception on the bit error rate of underwater wireless optical communication (UWOC) system under the condition of anisotropic ocean turbulence, Gaussian beam transmission was adopted to pass through an anisotropic ocean turbulence channel under pulse position modulation. The signal was then received though the apertureby the acceptor, the effects of ocean turbulence parameters, transmission distance, average gain of avalanche photodiode ( APD), and modulation order on the bit error rate of the system under different receiving aperture and anisotropy factor were numerically simulatedby introducing the anisotropic ocean turbulence structure constant and analyzing the formation principle of scintiilation and scintiilation index under the condition of anisotropic ocean turbulence. The results show that under the same anisotropy factor and ocean turbulence parameters, the bit error rate performance of the system can be effectively improved by large aperture receiver. The larger the anisotropy factor, the better the system communication performance for the same aperture diameter and ocean turbulence parameters. The bit error rate performance of the system becomes better when the ratios of mean square temperature dissipation rate, temperature, and salinity contribution to the variation of ocean power spectrum are smaller, while the turbulent kinetic energ dissipation rate and kinetic viscosity are larger and the transmission distance is shorter. The performance of system communication is optimal when the APD gain is 100 or 150. The optimal system communication performance is achieved when the modulation order M = 8, and the degree of system bit error rate variation is almost saturated when M>64. This study provides a reference for UWOC system platform construction and performance estimation. [ABSTRACT FROM AUTHOR]

Copyright of Telecommunications Science is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Channel capacity reflects the ability of the system to transmit information without errors.The path loss and impulse response of the system were calculated based on traversing tiny unit method,and then the frequency response of the system was obtained by the discrete Fourier transform of the impulse response sampling sequence,and the 3 dB bandwidth of the system was calculated.Considering the shot noise caused by signal light,the signal-to-noise ratio of the system was obtained according to the quantum limit method,and then the relationship between the channel capacity and the geometric parameters of transmitter and receiver in non-line-of-sight noncoplanar ultraviolet communication system were simulated and analyzed by Shannon formula.The results show that the channel capacity decreases with the increase of the off axis angle and the communication distance.When the elevation angles of transmitter and receiver are less than 40°,the channel capacity decreases rapidly with the increase of the elevation angles of transmitter and receiver,and the transmitter elevation angle has a great influence on the channel capacity.The system channel capacity is almost constant with the increase of divergence angle,and the larger the receiver field of view angle,the greater the system channel capacity.

Copyright of Study on Optical Communications / Guangtongxin Yanjiu is the property of Study on Optical Communications Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Space optical communication has been a hot topic in modern communication system research, because it has many advantages, such as good secrecy, large information capacity, strong anti-interference ability, and so on. Pulse position modulation (PPM) is an excellent modulation method. In view of the low rate of information transmission by a space optical communication system, an improved "empty-empty-zero" physical frame format is designed to improve its transmission rate. In view of the actual space laser digital receiver, the frame synchronization algorithm is designed in this paper. Based on the physical frame format, this paper focuses on the design of frame synchronization algorithm. In order to deal with the change of noise and other parameters, an adaptive threshold setting is proposed. Considering the engineering implementation, a simplified correlation filtering implementation method is proposed. Finally, we designed the reception prototype system based on FPGA. The Matlab simulation, online simulation and experimental verification prove that the proposed method is correct and reliable.

In order to systematically research the factors affecting coupling efficiency, the coupling model of semiconductor laser and single-mode fiber was established and an automatic coupling platform was built by means of simulation and experiment. Theoretical analysis and experimental verification were carried out, and the relationship between coupling efficiency of the model and displacement sensitivity of each direction and the relationship between coupling efficiency and tolerance of each direction in the actual coupling process were obtained. The results show that, coupling efficiency is most sensitive to horizontal displacement, followed by angular rotation and longitudinal displacement. The maximum coupling efficiency of simulation and experiment is 64.29% and 51.46% respectively. The error of simulation and experiment is within a reasonable range, thus the results are highly credible. The results are helpful to improve the packaging coupling efficiency of practical photoelectric devices. [ABSTRACT FROM AUTHOR]

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Journal on Communication / Tongxin Xuebao is the property of Journal on Communications Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The summary of the 43rd European Conference on Optical Communication (ECOC) was introduced,and plenary presentations,workshops,tutorials,invited papers,post-deadline papers,as well as exhibition were discussed.The conference includes eight technical scopes:fibers,fiber devices and fiber amplifiers,integrated optoelectronic devices and optical processors,digital techniques for optical communication systems,transmission subsystems and optical network elements,datacom and computercom hardware,point-to-point transmission links,core,metro,and data center networks,access,local area and indoor networks.