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当前目录 第22卷 第3期

Author Affiliations
Abstract
School of Information and Communication Engineering, Dalian University of Technology, Dalian 116024, China
This paper has proposed an experimental system for non-orthogonal multiple access (NOMA) wireless optical communication in challenging underwater turbulent environments, employing the gallium nitride (GaN)-based micro-LED array. This design of the GaN-based micro-LED array enables the independent transmission of signals from distinct data streams within the NOMA framework, facilitating direct optical power-domain superposition of NOMA signals. The experimental setup involves emulating oceanic turbulence channels, characterized by varying the level of scintillation intensity, to thoroughly investigate the bit error rate (BER) performance. The outcomes unequivocally demonstrate the superiority of our proposed NOMA scheme, as compared to conventional circuit-driven optical NOMA systems utilizing fixed LED array grouping, particularly in the presence of turbulent underwater channels. The proposed NOMA scheme exhibits consistently superior BER performance and maintains excellent linearity at the lower frequencies while effectively mitigating signal distortion at the higher frequencies.
optical non-orthogonal multiple access gallium nitride-based micro-LED array oceanic turbulence channels bit error rate 
Chinese Optics Letters
2024, 22(3): 030101
Author Affiliations
Abstract
1 Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
2 College of Materials Science and Opto-electronics Technology, University of Chinese Academy of Sciences, Beijing 100049, China
3 Beijing Huairou Instruments and Sensors Co., Ltd., Beijing 101400, China
4 Beijing Institute of Automation and Control Equipment, Key Laboratory of National Defense Science and Technology of Inertial Technology, Beijing 100074, China
Integrated optical gyroscopes (IOGs) have been an efficient tool for numerous applications in various fields, including inertial navigation, flight control, and earthquake monitoring. Here, we review the progress of integrated optical gyroscopes based on two categories of integrated interferometric optical gyroscopes (IIOGs) and integrated resonant optical gyroscopes (IROGs).
integrated optical gyroscopes interferometric optical gyroscopes integrated resonant optical gyroscopes 
Chinese Optics Letters
2024, 22(3): 031302
Author Affiliations
Abstract
1 College of Science, Kunming University of Science and Technology, Kunming 650093, China
2 College of Electronic Science and Engineering, Jilin University, Jilin 130012, China
The silicon-based arrayed waveguide grating (AWG) is widely used due to its compact footprint and its compatibility with the mature CMOS process. However, except for AWGs with ridged waveguides of a few micrometers of cross section, any small process error will cause a large phase deviation in other AWGs, resulting in an increasing cross talk. In this paper, an ultralow cross talk AWG via a tunable microring resonator (MRR) filter is demonstrated on the SOI platform. The measured insertion loss and minimum adjacent cross talk of the designed AWG are approximately 3.2 and -45.1 dB, respectively. Compared with conventional AWG, its cross talk is greatly reduced.
SOI platform arrayed waveguide grating cross talk microring filter array thermo-optic effect 
Chinese Optics Letters
2024, 22(3): 031303
Author Affiliations
Abstract
1 Henan Key Laboratory of Magnetoelectronic Information Functional Materials, School of Physics and Electronic Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002, China
2 State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
A passively switchable erbium-doped fiber laser based on alcohol as the saturable absorber (SA) has been demonstrated. The SA is prepared by filling the gap between two optical patch cords with alcohol to form a sandwich structure. The modulation depth of the alcohol–SA is measured to be 6.4%. By appropriately adjusting the pump power and the polarization state in the cavity, three kinds of mode-locked pulse patterns can be achieved and switched, including bright pulse, bright/dark soliton pair, and dark pulse. These different soliton emissions all operate at the fundamental frequency state, with a repetition rate of 20.05 MHz and a central wavelength of ∼1563 nm. To the best of our knowledge, this is the first demonstration of a switchable soliton fiber laser using alcohol as the SA. The experimental results further indicate that organic liquid-like alcohol has great potential for constructing ultrafast lasers.
optical solitons fiber lasers alcohol pulsed lasers 
Chinese Optics Letters
2024, 22(3): 031403
Author Affiliations
Abstract
1 Institute of Microscale Optoelectronics, College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518060, China
2 Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, China
We demonstrate the generation of a unique regime of multiple solitons in a Tm-doped ultrafast fiber laser at ∼1938.72 nm. The temporal pulse-to-pulse separation among the multiple solitons, 10 in a single-pulse bunch, increases from 0.89 ns to 1.85 ns per round trip. In addition, with the increasing pump power, the number of bunched solitons increases from 3 up to 24 linearly, while the average time separation in the soliton bunch varies irregularly between ∼0.80 and ∼1.52 ns. These results contribute to a more profound comprehension of nonlinear pulse dynamics in ultrafast fiber lasers.
mode-locked fiber laser multiple solitons pump hysteresis pulse-to-pulse interval 
Chinese Optics Letters
2024, 22(3): 031405
Author Affiliations
Abstract
1 Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, School of Biomedical Engineering, Shenzhen University Medical School, Shenzhen 518060, China
2 Key Laboratory of Opto-electronic Information Science and Technology of Jiangxi Province, Nanchang Hangkong University, Nanchang 330063, China
3 College of Physics and Optoelectronics Engineering, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen University, Shenzhen 518060, China
4 Department of Bioengineering and COMSET, Clemson University, Clemson SC 29634, US
Wide-field linear structured illumination microscopy (LSIM) extends resolution beyond the diffraction limit by moving unresolvable high-frequency information into the passband of the microscopy in the form of moiré fringes. However, due to the diffraction limit, the spatial frequency of the structured illumination pattern cannot be larger than the microscopy cutoff frequency, which results in a twofold resolution improvement over wide-field microscopes. This Letter presents a novel approach in point-scanning LSIM, aimed at achieving higher-resolution improvement by combining stimulated emission depletion (STED) with point-scanning structured illumination microscopy (psSIM) (STED-psSIM). The according structured illumination pattern whose frequency exceeds the microscopy cutoff frequency is produced by scanning the focus of the sinusoidally modulated excitation beam of STED microscopy. The experimental results showed a 1.58-fold resolution improvement over conventional STED microscopy with the same depletion laser power.
stimulated emission depletion structured illumination microscopy superresolution microscopy 
Chinese Optics Letters
2024, 22(3): 031701
Author Affiliations
Abstract
1 Institute of Electromagnetics and Acoustics and Department of Physics, College of Physical Science and Technology, Xiamen University, Xiamen 361005, China
2 Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
3 School of Physical Science and Technology and Jiangsu Key Laboratory of Thin Films, Soochow University, Suzhou 215006, China
Vortex waves with orbital angular momentum (OAM) are a highly active research topic in various fields. In this paper, we design and investigate cylindrical metagratings (CMs) with an even number of unit cells that can efficiently achieve vortex localization and specific OAM selective conversion. The multifunctional manipulation of vortex waves and the new OAM conservation law have further been confirmed through analytical calculations and numerical simulations. In addition, we qualitatively and quantitatively determine the OAM range for vortex localization and the OAM value of vortex selective conversion and also explore the stability for performance and potential applications of the designed structure. This work holds potential applications in particle manipulation and optical communication.
vortex waves cylindrical metagratings vortex localization high-efficiency transmission vortex selective conversion 
Chinese Optics Letters
2024, 22(3): 033601
Author Affiliations
Abstract
1 State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
2 School of Physics, Ningxia University, Yinchuan 750021, China
3 Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
4 Collaborative Innovation Center of Light Manipulations and Applications, Shandong Normal University, Jinan 250358, China
Lithium niobate is a material that exhibits outstanding electro-optic, nonlinear optical, acousto-optic, piezoelectric, photorefractive, and pyroelectric properties. A thin-film lithium niobate photonic crystal can confine light in the sub-wavelength scale, which is beneficial to the integration of the lithium niobate on-chip device. The commercialization of the lithium niobate on insulator gives birth to the emergence of high-quality lithium niobate photonic crystals. In order to provide guidance to the research of lithium niobate photonic crystal devices, recent progress about fabrication, characterization, and applications of the thin-film lithium niobate photonic crystal is reviewed. The performance parameters of the different devices are compared.
lithium niobate photonic crystal integrated optics 
Chinese Optics Letters
2024, 22(3): 033602