Huang Junxiang   Fu Tao   Li Haiou   Shou Zhaoyu   Gao Xi  

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A metal-graphene hybrid metasurface polarization converter is designed in this letter. The unit cell of the hybrid metasurface is composed of a butterfly-shaped structure whose branches are connected by multi-layer graphene sheets. The proposed device can be reconfigured from linear-to-circular polarization to cross-polarization by changing the Fermi energy of graphene. The simulation results show that for 3-layer graphene, the device acts as a linear-to-circular polarization converter when EF = 0 eV, and switches to a cross-polarization converter when EF = 0.5 eV. Compared with single-layer graphene, the device with 3-layer graphene can maintain the cross-polarization conversion performance under low Fermi energy. Furthermore, two equivalent circuits in the x and y directions are developed to understand the working mechanism of the device.

       PDF全文 (下载：0)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

miaomao He   sheng Chen   quanxin Na   shaojuan Luo   haiyong zhu   Li Ying   changwen Xu   Fan Dianyuan  

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A power-scaled laser operation of Pr:YLF crystal at 720.9 nm pumped by a 443.6 nm laser diode module was demonstrated. The 20 W module was used to pump the Pr:YLF crystal and a maximum output power of 3.03 W with slope efficiency of 30.04% was obtained. In addition, a 5W blue laser diode (LD) was also used to pump the Pr:YLF laser and a maximum output power of 0.72 W was obtained at room temperature. The output power was limited by the wavelength mismatch between the single-emitter LD and the absorption peak of the crystal.

       PDF全文 (下载：1)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Xie Kun   Liu Wenguang   Qiong Zhou   Jiang zongfu   Xi Fengjie   Xu Xiaojun  

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In this paper, a novel system for adaptively correcting the phase of a dynamic multimode beam is proposed. While using merely one spatial light modulator, the phase measurement of the 1st order diffraction pattern and the correction of the 0th diffraction order are simultaneously realized. The real-time experimental result is obtained at a control rate of 10 Hz. The power-in-the-bucket value is improved from 38.5% to 61.8% even with fundamental mode content that is consistently below than 30%. To the best of our knowledge, this is the first implementation of real-time adaptive correction of the entire multimode beam.

       PDF全文 (下载：2)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

zhang wei   Gao Weiqing   liang chen   hui jiang   xiong zhang   xiu zhang   yun gao   Zhou Yong   Liao Meisong   Suzuki Takenobu   Yasutake Ohishi Yasutake Ohishi   xie kang  

      摘要 + 此论文可免费阅读 (可能需要登录)

Brillouin gain spectra (BGS) in an As2Se3 photonic crystal fiber (PCF) are investigated numerically. The profiles of the BGS are simulated by calculating the characteristics of different-order optical and acoustic waves in the PCFs with different core diameters. For the small-core PCF, there are two peaks in BGS, but there is only one peak for the large-core PCF. We also reveal that in the small-core PCF, the difference of Brillouin frequency shift between the LP01 and LP11 mode is obvious, while it is not obvious in the large-core PCF. The Brillouin threshold increases with the core diameter increasing.

       PDF全文 (下载：1)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Lu Guojun   Liu Hongzhan  

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In order to improve the signal-to-noise ratio and mitigate the damage of noise to the communication quality, an effective interference suppression algorithm, which is based on the improved density-based spatial clustering of applications with noise (DBSCAN) algorithms, is proposed for visible light communication (VLC) system using the com-plementary metal oxide semiconductor (CMOS) image sensor as receiver (Rx). Experimental result show that the algorithm can learn the region where the payload data is located, filter out the noise data and can greatly decreased the interference. The effect of the algorithm is also studied through BER performance.

       PDF全文 (下载：7)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Zheng Kangjia   Zou Weiwen   Yu Lei   Qian Na   Chen Jianping  

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We investigate a channel-interleaved photonic analog-to-digital converter (PADC) system’s ability to work stably over a long duration with optimal driving voltage. The influence of optimum bias point drift of a Mach-Zehnder modulator (MZM)-based photonic switch on this system was analyzed theoretically and experimentally. The feasibility of extracting feedback signals from the PADC system was derived. A high-stability channel-interleaved PADC was constructed by extracting a feedback signal from a parallel demultiplexing module to control the MZM-based photonic switch’s driving voltage. Consequently, the amplitude mismatch between the channels was limited to within 0.3 dB over 12 hours of operation.

       PDF全文 (下载：0)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Yang Dan   Huang Yongqing   Liu Tao   Ma Xiaokai   Duan Xiaofeng   Liu kai   Ren Xiaomin  

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We have designed and fabricated zero-bias operational two-element symmetric-connected photodetector arrays (SC-PDA). The designed SC-PDA have higher saturation currents, larger RF power, and better frequency responses than the single PD under zero bias. The bias-free SC-PDA with 15 μm diameter of each PD demonstrated a 3 dB bandwidth of 19.4 GHz at 0.5 mA. The RF saturation photocurrent and maximum RF output power of the SC-PDA with 40 μm, 50 μm, and 60 μm diameter under zero bias is over 9.31 mA and -5.86 dBm at 3 GHz, 14.52 mA and 1.17 dBm at 1GHz, 13.72 mA and -1.76 dBm at 1 GHz, respectively.

       PDF全文 (下载：8)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Cheng Jiaju   Luo Jianwen  

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For fluorescence molecular tomography (FMT), image-quality could be improved by incorporating sparsity constrain. L1 norm regularization method is proved better than L2 norm like Tikhonov regularization. However, Tikhonov method was found capable of achieving similar quality at high iteration cost by adopting zeroing strategy. By studying the reason, a Tikhonov-regularization-based projecting sparsity pursuit method was proposed which reduces the iterations significantly and achieves good image-quality. It was proved in phantom experiments through time-domain FMT that the method could obtain higher accuracy and less over-sparsity and is more applicable for heterogeneous-target reconstruction, compared with several regularization methods implemented in this paper.

       PDF全文 (下载：4)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Saadon Haitham   Abbas Saeed   Shubar Mohammed  

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Bi2S3-xSex/PMMA nanocomposite films were prepared using a microwave assisted synthesis with different compositions of x. Crystal structure, surface morphology, and optical properties were performed to characterize the prepared nanocomposite films. The crystallinity and optical band gap of the prepared Bi2S3-xSex/PMMA were affected by x. The prepared samples showed a blue shift in the absorption edge. The laser power dependent nonlinear refraction and absorption of Bi2S3-xSex/PMMA nanocomposite films were investigated by using the Z-scan technique. The optical nonlinearity of the nanocomposite films exhibited switchover from negative nonlinear refraction to positive nonlinear refraction to negative nonlinear refraction effect, and from saturable absorption to reverse saturable absorption to saturable absorption with increase and decrease in the composition. An interesting of all-optical figures of merit was reported to assess the nanocomposite films for a practical device. It were calculated the device all-figures of merit based on the nonlinear response, which is important for all-optical switching device. The results demonstrate that the optimized all-optical figures of merit can be achieved by adjusting the composition and input laser power, which can be used for the design of different all-photonic devices, as well as the results of nonlinear switching behavior can be open new possibility of using the nanocomposite films in laser Q-switching and mode-locking.

       PDF全文 (下载：1)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Gao Yachen   Shuang Chen   Suying Yang   Huang Yan   Weiyan Jiao   Guanghua Fan  

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The dipole resonances of gold nanocages were investigated theoretically using finite difference time domain (FDTD). The results show that field enhancement is obtained at the walls of the gold nanocages. It is believed that the effect can cause strong optical nonlinear property. To test the hypothesis, the nonlinear absorption was investigated using broadband 5ns Z-scan. It was found that, at low intensities the sample shows saturation absorption (SA), while at higher intensities, a switch from SA to reverse saturation absorption (RSA) occurs. Moreover, the nonlinear absorption of sample is sensitively wavelength-dependent, and in resonant region saturation intensity is the largest.

       PDF全文 (下载：6)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Yuan Xupeng   Guo Xinjun   Zhao Miao   Li Yao   Gan Zongsong   Ruan Hao  

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In this Letter, new approach of optical tape for high capacity multilayer data storage is proposed. We show that a length of 5 cm and width of 2 cm soft and transparent optical tape can be used for two-photon three-dimensional bit data storage. We successfully demonstrate writing and reading of six layers of data storage with a transverse bit separation of 2 μm and an axial separation of 2.5 μm in a tetraphenylethylene-doped photobleaching polymer. Thus, the optical tape what we put forward in the experiment can help people realize true big data storage in the future likes magnetic tape. This method significantly paves a novel way for solving big data storage problem.

       PDF全文 (下载：3)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Xiao ZhiLei   Quan Wei   Xu SongPo   Yu ShaoGang   Wang YanLan   Zhao Meng   Wei MingZheng   Zhou Yu   Lai Xuan-yang   Chen(陈京) Jing   Liu Xiaojun  

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Coulomb potential may induce a significant angular offset to the 2-dimensional photoelectron momentum distributions for atoms subject to strong elliptically polarized laser field. In the attoclock experiment, this offset usually cannot easily be disentangled from the contribution of tunneling delay and poses a main obstacle to the precise measurement of tunneling delay. Based on semiclassical calculations, here we propose a method to extract the equivalent temporal offset induced solely by Coulomb potential (TOCP) in an attoclock experiments. Our calculations indicate that, at constant laser intensity, the TOCP show distinctive wavelength dependence laws for different model atoms and the ratio of the target atom's TOCP to that of H becomes insensitive to wavelength and linearly proportional to (2I_p )^(-3⁄2), where I_p is the ionization potential of the target atom. This wavelength and I_p dependence of TOCP can be further applied to extract the Coulomb potential influence. Our work paves the way for an accurate measurement of the tunneling delay in the tunneling ionization of atoms subject to intense elliptically polarized laser field.

       PDF全文 (下载：3)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Fan Haibo   Mu Yining   Liu ChunYang   zhu yan   Liu Guozhen   Wang Shuai   Li Yanzheng   Du Peng  

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Aiming at the application requirements of information optics, this paper proposed a perovskite quantum dot random lasing pumping method suitable for high-speed modulation. At the same time, the luminescence characteristics of perovskite quantum dot films under electron beam pumping conditions are analyzed, and the random lasing mechanism of electron beam pumping CsPbBr3 quantum dot films is revealed. Finally, It is confirmed that perovskite quantum dots are easy to realize random lasing under electron beam pumping conditions.

       PDF全文 (下载：13)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Li Zhenhua   Cheng Chuanfu   liu Hanping   Li Dawei   Xu Shicai   Liu Huilan   Zhang Junye   Zhang Suzhen  

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In this Letter, we fabricate integrated metasurface of encoded dynamic phases and experimentally generate nonconventional Kagome-type lattices of no second-order phase vortices. The thin metasurface acts analogous to an integration of three conventional optical elements, i.e., six pinholes located at the vertices of two concentric regular triangles of size ratio 1:2, six transparent discs of different thicknesses to introduce a total phase shift difference of 6π and a Fourier lens with focal length in micro-scale. Kagome lattice with required vortex distribution is realized at the “focal” plane of the metasurface under illumination of plane wave.

       PDF全文 (下载：11)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Zhang Chi   Fu Dongying   Xia Chunli   Yao Lishuang   Lu Chunlian   Sun weimin   Liu Yongjun  

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In this paper, a dye-doped cholesteric liquid crystal (DDCLC) filled hollow glass microsphere is demonstrate to be a resonator with good temperature response. A diglycerol layer is used to wrap the DDCLCs microdroplet to keep it steady and control its orientation. The whispering gallery mode (WGM) lasing and photonic band gap (PBG) lasing caused by two different mechanisms were obtained under the pump of a pulsed laser, and the temperature response of these two kind of lasing were studied. For the liquid crystal and chiral material used in this paper, both the WGM lasing and the PBG lasing have a blue shift in wavelength with increasing temperature.

       PDF全文 (下载：6)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Cao Liang   YU Yang   Xiao Min   Yang Junbo   Zhang Xue-liang   Meng Zhou  

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In order to meet the practical needs of all-fiber CTD sensor with high sensitivity, compact structure and easy packaging, this paper uses a microfiber coupler combined with Sagnac loop (MCSL) reflective photonic device to conduct salinity, temperature and deep sensing experiments.These MCSLs’ dynamic range and resolution of salinity, temperature, and depth can meet the requirements of actual marine environment monitoring. This structure opens up a new design idea for the practical research of MC-based marine environmental parameter sensor.

       PDF全文 (下载：3)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Ikawa Shohei   Takada Naoki   Araki Hiromitsu   Niwase Hiroaki   Sannomiya Hiromi   Nakayama Hirotaka   Oikawa Minoru   Mori Yuichiro   Kakue Takashi   Shimobaba Tomoyoshi   Ito Tomoyoshi  

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We demonstrate real-time three-dimensional (3D) color video using color electroholographic system with a cluster of multiple-graphics processing units (multi-GPU) and three spatial light modulators (SLMs) corresponding to respective red, green, and blue (RGB)-colored reconstructing lights. The multi-GPU cluster has a computer-generated hologram (CGH) display node containing a GPU, for displaying calculated CGHs on SLMs, and four CGH calculation nodes using 12 GPUs. The GPUs in the CGH calculation node generate CGHs corresponding to RGB reconstructing lights in a 3D color video using pipeline processing. Real-time color electroholography was realized for a 3D color object comprising approximately 21,000 points per color.

       PDF全文 (下载：3)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Peng Mingying   wang yafei   li xingyu   wu jiamin   peng xiulin   Cao Jiangkun   Yang Changsheng   Xu Shanhui   Yang Zhongmin  

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Nd3+ doped fiber lasers at around 900 nm based on the 4F3/2 → 4I9/2 transition have obtained much research attention since they can be used as the laser sources for generating pure blue fiber lasers through frequency doubling technique. Here, all-fiber laser at 915 nm was realized by polarization-maintaining Nd3+ doped silica fiber. A net gain per unit length of up to 1.0 dB/cm at 915 nm was obtained from a 4.5 cm fiber, which to our best knowledge is the highest gain coefficient reported in this kind of silica fiber. The optical-to-optical conversion efficiency varies with active fiber length and the reflectivity of output fiber Bragg grating (FBG), presenting an optimal value of 5.3% at 5.1 cm fiber length and 70% reflectivity of LR-FBG. Additionally, the linear DBR short cavity was constructed to explore its potential in realizing single frequency 915 nm fiber laser. The measurement result of longitudinal mode properties shows it is still multi-longitudinal modes laser operation with 55 mm laser cavity. These results indicate that the Nd3+ doped silica fiber could be used to realize all-fiber laser at 915 nm, which presents potential to be the seed source of high power fiber laser.

       PDF全文 (下载：3)        Chinese Optics Letters ，年第卷第期 pp.      

Usman Muhammad   Zabit Usman   D. Bernal Olivier   Raja Gulistan  

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Self-mixing interferometry (SMI) is an attractive sensing scheme which typically relies on mono-modal operation of employed laser diode. However, change in laser modality can occur due to change in operating conditions. So, detection of occurrence of multi-modality in SMI signals is necessary to avoid erroneous metric measurements. Typically, processing of multi-modal SMI signals is a difficult task due to the diverse and complex nature of such signals. However, the proposed techniques can significantly ease this task by identifying the modal state of SMI signals with 100% success rate, so that interferometric fringes can be correctly interpreted for metric sensing applications.

       PDF全文 (下载：3)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Ma Rende   Wan Luxue   Liu Xiuhao   Li Xiaoping   JIANG J.F.   夏 云杰  

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The polarization of D-shaped fiber is modulated after immersing it in the magnetic fluid (MF) and applying a magnetic field. Theoretical analysis predicts that magneto-optical dichroism of MF plays key role in the light polarization modulation. During the light polarization modulation, the evanescent wave polarized parallel to the magnetic field has greater loss than its orthogonal component. The light polarization of D-shaped fiber with a wide polished surface can be modulated easily. High concentration MF and large magnetic field all have great ability to modulate light polarization.

       PDF全文 (下载：6)        Chinese Optics Letters ，2020年第18卷第1期 pp.01      

Sait mohammed   Sun Xiaobin   Alkhazragi Omar   Alfaraj Nasir   Kong Meiwei   Ng Tien   Ooi B. S.  

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Conventional line-of-sight underwater wireless optical communication (UWOC) links suffer from huge signal fading in the presence of oceanic turbulence due to misalignment, which is caused by variations in the refractive index in the water. Non-line-of-sight (NLOS) communication, a novel underwater communication configuration, which has eased the requirements on the alignment, is supposed to enhance the robustness of the UWOC links in the presence of such turbulence. This paper experimentally and statistically studies the impact of turbulence that arises from temperature gradient variations and the presence of different air bubble populations on NLOS optical channels. The results suggest that temperature gradient-induced turbulence causes negligible signal fading to the NLOS link. Furthermore, the presence of air bubbles with different populations and sizes can enhance the received signal power by seizing the scattering phenomena from an ultraviolet 377-nm laser diode.

       PDF全文 (下载：3)        Chinese Optics Letters ，2019年第17卷第10期 pp.10      

FEI CHAO   Hong Xiaojian   Du Ji   Zhang Guowu   Wang Yuan   Shen Xiaoman   Lu Yuefeng   Guo Yang   He Sailing  

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In this paper, recent advances in underwater wireless optical communication (UWOC) are reviewed for both LED- and LD-based systems, mainly from a perspective of advanced modulation formats. Volterra series based nonlinear equalizers, which can effectively counteract the nonlinear impairments induced by the UWOC system components, are discussed and experimentally demonstrated. Both the effectiveness and robustness of the proposed Volterra nonlinear equalizer in UWOC systems under different water turbidity are validated. To further approach the Shannon capacity limit of the UWOC system, probabilistic constellation shaping (PCS) technique is introduced, which can overcome the inherent gap between a conventional regular quadrature amplitude modulation (QAM) format and the Shannon capacity of the channel. The experimental results have shown significant system capacity improvement compared to the cases using a regular QAM.

       PDF全文 (下载：4)        Chinese Optics Letters ，2019年第17卷第10期 pp.10      

Chi Nan   Hu Fangchen  

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Underwater visible light communication (UVLC) is expected to act as an alternative candidate in next-generation underwater 5G wireless optical communications. To realize high-speed UVLC, the challenge is that the absorption, scattering, turbulence of water medium and the nonlinear response from imperfect optoelectronic devices, which can bring large attenuation and nonlinearity penalty. Nonlinear adaptive filters are commonly used in optical communication to compensate for nonlinearity. In this paper, we compare RLS based Volterra filter, LMS based DP filter and LMS based Volterra filter in terms of performance and computational complexity in underwater visible light communication. We experimentally demonstrate 2.325 Gb/s transmission at a distance of 1.2 m water with a commercial blue LED. Our goal is to assist the readers in refining the motivation, structure, performance and cost of powerful nonlinear adaptive filters in the context of future underwater visible light communication in order to tap into hitherto unexplored applications and services.

       PDF全文 (下载：2)        Chinese Optics Letters ，2019年第17卷第10期 pp.10      

Tian Pengfei   Cui Xugao   Chen Honglan   Wang Peiyao   Liu Xiaoyan   Chen Xinwei   Zhou Gufan   Zhang Shuailong   Lu Jie   Qiu Pengjiang   Qian Zeyuan   周 小林   Fang Zhilai   Zheng Lirong   Liu Ran  

      摘要 + 此论文可免费阅读 (可能需要登录)

In this work, a blue gallium nitride (GaN) micro-LED based underwater optical communication (UWOC) system was built, and UWOCs with varied Maalox, chlorophyll and sea salt concentrations were studied. Data transmission performance of the UWOC and the influence of light attenuation were investigated systematically. Maximum data transmission rates at the distance of 2.3 m were 933, 800, 910 and 790 Mbps for experimental conditions with no impurity, 200.48 mg/m3 Maalox, 12.07 mg/m3 chlorophyll and 5kg/m3 sea salt, respectively, much higher than previously reported systems with commercial LEDs. It was found that increasing chlorophyll, Maalox and sea salt concentrations in water resulted in an increase of light attenuation, which led to the performance degradation of the UWOC. Further analysis suggests two light attenuation mechanisms, e.g. absorption by chlorophyll and scattering by Maalox, are responsible for the decrease of maximum data rate and the increase of bit error rate. Based on the absorption and scattering models, excellent fitting to the experimental attenuation coefficient can be achieved and light attenuation by absorption and scattering at different wavelengths was also investigated. We believe this work instructive to apply UWOC for practical applications.

       PDF全文 (下载：10)        Chinese Optics Letters ，2019年第17卷第10期 pp.10      

Cossu G.  

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The growing number of underwater activities is giving momentum to the development of new technologies, such as buoys, Remotely Operated Vehicles (ROVs) and Autonomous Underwater Vehicles (AUVs). The data collected by these vehicles needs to be transmitted to a central unit with high speed. Clearly, wired solution are not suitable, since they strongly impact the mobility. In this scenario, a promising solution is offered by Underwater Optical Wireless Communication (UOWC) technology, which can achieve both high-speed and wireless operation. Here, we provide a comprehensive survey on the challenges, the experimental realizations and the state of the art in UOWC researches.

       PDF全文 (下载：3)        Chinese Optics Letters ，2019年第17卷第10期 pp.10      

Xu Jing  

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Foreseeing the proliferation of underwater vehicles and sensors, underwater wireless optical communication (UWOC) is a key enabler for ocean exploration, with strong competitiveness in short-range bandwidth-intensive applications. We provide a tutorial on the basic concepts and essential features of UWOC as well as an overview of work being conducted in this field. Research challenges, arising from the characteristics of underwater channels, and possible roadmaps are discussed in detail. This review is expected to be of great use to the link designers of this field.

       PDF全文 (下载：8)        Chinese Optics Letters ，2019年第17卷第10期 pp.10      

Chen Lian-Kuan   SHAO Yingjie   Deng Rui  

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We systematically investigate the bubble-induced performance degradation for underwater wireless optical communication (UOWC) with different bubble sizes and positions. By using different transmit and receive diversities, we investigate the effectiveness of spatial diversity on the mitigation of the bubble-induced impairment to the UOWC link. With the help of a 2×2 MIMO using repetition coding (RC) and maximum ratio combining (MRC), a robust 780-Mbit/s UOWC transmission is achieved. The corresponding outage probability can be significantly reduced from 34.6% for the system without diversity to less than 1%.

       PDF全文 (下载：4)        Chinese Optics Letters ，2019年第17卷第10期 pp.10      

Xing Fangyuan   Yin Hongxi   Jing Lianyou  

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This letter investigates the performance of the two-way multi-hop system for underwater optical wireless communications. With the decode-and-forward (DF) relaying, the two-way multi-hop system is modeled, where the effects of absorption, scattering, and oceanic turbulence are all taken into account. An exact closed-form expression for outage probability is derived under the assumption that the oceanic turbulence obeys a log-normal distribution. Numerical results demonstrate the impacts of various parameters on the outage performance and indicate that the two-way multi-hop system significantly improves the performance in comparison to both the one-way multi-hop system and the two-way two-hop system.

       PDF全文 (下载：5)        Chinese Optics Letters ，2019年第17卷第10期 pp.10      

Chen Daomin   Wang Jiemei   Li shangbin   Xu Zhengyuan  

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The received signal intensity fluctuation and communication performance of an underwater optical wireless communication (UOWC) system under the air bubble effects are experimentally investigated. For different bubble density and size, Lognormal, Gamma, Weibull and generalized extreme value distributions are tested to fit the fluctuation of the signal intensity at the receiving end. The best fitting distribution is found to vary with bubble parameters. The communication system performance with OOK and pulse position modulation is further studied.

       PDF全文 (下载：5)        Chinese Optics Letters ，2019年第17卷第10期 pp.10      

Guo Haichao   Shan Tao   Li Li   Zhang Li   Li Xiaojun   Gao Han  

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A sunlight communication system is proposed that uses Sr2Si5N8:Eu2+ phosphors to concentrate sunlight signals in strong background-light noise; thus, a wide spectrum sunlight communication system is converted into a narrow spectrum one. A communication method is proposed to enable compression to the dark line H-α (656.28 nm) spectrum. A 50% solar energy conversion efficiency is achieved, with a 0.3 μs code delay, a 0.2 μs code rise time (20%–80%), and a 96% optical transmittance. Experimental results show that phosphors enhance the sunlight intensity 1.5 times with the same distance. This method has immense potential in future long-distance sunlight communication.

       PDF全文 (下载：5)        Chinese Optics Letters ，2019年第17卷第12期 pp.12