Review on Semantic Segmentation of Road Scenes
Wang Longfei, and Yan Chunman
Image semantic segmentation is an important research field of computer vision and also one of the key technologies for scene understanding. In the field of unmanned driving, high-quality semantic segmentation of road scenes provides a guarantee for the safe driving of autonomous vehicles. First, this paper starts with the definition of semantic segmentation of road scenes and discusses the current challenges in this field. Second, this paper divides the semantic segmentation technology into a traditional segmentation technology, a traditional segmentation technology combined with deep learning and a segmentation technology based on deep learning, focuses on the semantic segmentation technology based on deep learning, and elaborates it according to three different network training methods of strong supervision, weak supervision and unsupervison. Then, the datasets and performance evaluation indicators related to the semantic segmentation of road scenes are summarized and compared, and the segmentation results using the common image semantic segmentation methods are analyzed. Finally, the challenges faced by the road scene semantic segmentation technologies and the future development direction are prospected.
  • Jun. 18, 2021
  • Laser & Optoelectronics Progress
  • Vol.58 Issue, 12 1200002 (2021)
  • DOI:10.3788/LOP202158.1200002
Single-Molecule Localization Super-Resolution Microscopy and Its Applications
Yang Jianyu, Dong Hao, Xing Fulin, Hu Fen, Pan Leiting, and Xu Jingjun
Super-resolution microscopy invented at the beginning of the 21 st century has rapidly become a indispensable method in life science research owing to their nanoscale spatial resolution, low damage of sample preparation, and so on. Among a variety of super-resolution imaging techniques, single-molecule localization super-resolution microscopy (SMLM) with straightforward principle and outstanding spatial resolution gains more and more attention from researchers, thereby continuously making significant progress on the techniques and applications. Firstly, this paper reviewed the principle of SMLM and discussed some technical problems including the optical path building, the image reconstruction, and the drift correction. Two types of representative SMLMs were indroduced and discussed. Then, diversified multi-color SMLMs were introduced and their advantages and disadvantages were analyzed. The improvement of imaging parameters including the lateral/axial spatial resolution, imaging field, and imaging depth of SMLM was subsequently discussed. The research progress of correlated imaging of the SMLM combined with deep learning and SMLM combined with the electron microscope was further introduced. Moreover, the extraction and analysis methods of SMLM data were discussed. Finally, some important applications of SMLM in cell biology were listed and the development prospects of SMLM were discussed. We hope the present review could be a useful reference for the SMLM users and provides novel insights for them, thus promoting the in-depth applications of SMLM in life science research.
  • Jun. 18, 2021
  • Laser & Optoelectronics Progress
  • Vol.58 Issue, 12 1200001 (2021)
  • DOI:10.3788/LOP202158.1200001
Recent progress of physical failure analysis of GaN HEMTs
Cai Xiaolong, Du Chenglin, Sun Zixuan, Ye Ran, Liu Haijun, Zhang Yu, Duan Xiangyang, and Lu Hai
  • Jun. 17, 2021
  • Journal of Semiconductors
  • Vol.42 Issue, 5 051801 (2021)
  • DOI:10.1088/1674-4926/42/5/051801
Surface-enhanced Raman spectroscopy chips based on two-dimensional materials beyond graphene
Zhang Enqing, Xing Zhengkun, Wan Dian, Gao Haoran, Han Yingdong, Gao Yisheng, Hu Haofeng, Cheng Zhenzhou, and Liu Tiegen
Surface-enhanced Raman spectroscopy (SERS) based on two-dimensional (2D) materials has attracted great attention over the past decade. Compared with metallic materials, which enhance Raman signals via the surface plasmon effect, 2D materials integrated on silicon substrates are ideal for use in the fabrication of plasmon-free SERS chips, with the advantages of outstanding fluorescence quenching capability, excellent biomolecular compatibility, tunable Fermi levels, and potentially low-cost material preparation. Moreover, recent studies have shown that the limits of detection of 2D-material-based SERS may be comparable with those of metallic substrates, which has aroused significant research interest. In this review, we comprehensively summarize the advances in SERS chips based on 2D materials. As several excellent reviews of graphene-enhanced Raman spectroscopy have been published in the past decade, here, we focus only on 2D materials beyond graphene, i.e., transition metal dichalcogenides, black phosphorus, hexagonal boron nitride, 2D titanium carbide or nitride, and their heterostructures. We hope that this paper can serve as a useful reference for researchers specializing in 2D materials, spectroscopy, and diverse applications related to chemical and biological sensing.
  • Jun. 17, 2021
  • Journal of Semiconductors
  • Vol.42 Issue, 5 051001 (2021)
  • DOI:10.1088/1674-4926/42/5/051001
Waveguide external cavity narrow linewidth semiconductor lasers
Luo Chanchan, Zhang Ruiying, Qiu Bocang, and Wang Wei
Narrow linewidth light source is a prerequisite for high-performance coherent optical communication and sensing. Waveguide-based external cavity narrow linewidth semiconductor lasers (WEC-NLSLs) have become a competitive and attractive candidate for many coherent applications due to their small size, volume, low energy consumption, low cost and the ability to integrate with other optical components. In this paper, we present an overview of WEC-NLSLs from their required technologies to the state-of-the-art progress. Moreover, we highlight the common problems occurring to current WEC-NLSLs and show the possible approaches to resolving the issues. Finally, we present the possible development directions for the next phase and hope this review will be beneficial to the advancements of WEC-NLSLs.
  • Jun. 17, 2021
  • Journal of Semiconductors
  • Vol.42 Issue, 4 041308 (2021)
  • DOI:10.1088/1674-4926/42/4/041308
Latest advances in high-performance light sources and optical amplifiers on silicon
Liu Songtao, and Khope Akhilesh
Efficient light generation and amplification has long been missing on the silicon platform due to its well-known indirect bandgap nature. Driven by the size, weight, power and cost (SWaP-C) requirements, the desire to fully realize integrated silicon electronic and photonic integrated circuits has greatly pushed the effort of realizing high performance on-chip lasers and amplifiers moving forward. Several approaches have been proposed and demonstrated to address this issue. In this paper, a brief overview of recent progress of the high-performance lasers and amplifiers on Si based on different technology is presented. Representative device demonstrations, including ultra-narrow linewidth III–V/Si lasers, fully integrated III–V/Si/Si3N4 lasers, high-channel count mode locked quantum dot (QD) lasers, and high gain QD amplifiers will be covered.
  • Jun. 17, 2021
  • Journal of Semiconductors
  • Vol.42 Issue, 4 041307 (2021)
  • DOI:10.1088/1674-4926/42/4/041307
Beyond the 100 Gbaud directly modulated laser for short reach applications
Huang Jianou, Li Chao, Lu Rongguo, Li Lianyan, and Cao Zizheng
It is very attractive to apply a directly modulated laser (DML)-based intensity-modulation and direct-detection (IM/DD) system in future data centers and 5G fronthaul networks due to the advantages of low cost, low system complexity, and high energy efficiency, which perfectly match the application scenarios of the data centers and 5G fronthaul networks, in which a large number of high-speed optical interconnections are needed. However, as the data traffic in the data centers and 5G fronthaul networks continues to grow exponentially, the future requirements for data rates beyond 100 Gbaud are challenging the existing DML-based IM/DD system, and the main bottleneck is the modulation bandwidth of the DML. In this paper, the data rate demands and technical standards of the data centers and 5G fronthaul networks are reviewed in detail. With the modulation bandwidth requirements, the technical routes and achievements of recent DMLs are reviewed and discussed. In this way, the prospects, challenges, and future development of DMLs in the applications of future data centers and 5G fronthaul networks are comprehensively explored.
  • Jun. 17, 2021
  • Journal of Semiconductors
  • Vol.42 Issue, 4 041306 (2021)
  • DOI:10.1088/1674-4926/42/4/041306
Photonic devices based on thin-film lithium niobate on insulator
Yuan Shuai, Hu Changran, Pan An, Ding Yuedi, Wang Xuanhao, Qu Zhicheng, Wei Junjie, Liu Yuheng, Zeng Cheng, and Xia Jinsong
Lithium niobate on insulator (LNOI) is rising as one of the most promising platforms for integrated photonics due to the high-index-contrast and excellent material properties of lithium niobate, such as wideband transparency from visible to mid-infrared, large electro-optic, piezoelectric, and second-order harmonic coefficients. The fast-developing micro- and nano-structuring techniques on LNOI have enabled various structure, devices, systems, and applications. In this contribution, we review the latest developments in this platform, including ultra-high speed electro-optic modulators, optical frequency combs, opto-electro-mechanical system on chip, second-harmonic generation in periodically poled LN waveguides, and efficient edge coupling for LNOI.
  • Jun. 17, 2021
  • Journal of Semiconductors
  • Vol.42 Issue, 4 041304 (2021)
  • DOI:10.1088/1674-4926/42/4/041304
Hybrid material integration in silicon photonic integrated circuits
Chakravarty Swapnajit, Teng Min, Safian Reza, and Zhuang Leimeng
Hybrid integration of III–V and ferroelectric materials is being broadly adopted to enhance functionalities in silicon photonic integrated circuits (PICs). Bonding and transfer printing have been the popular approaches for integration of III–V gain media with silicon PICs. Similar approaches are also being considered for ferroelectrics to enable larger RF modulation bandwidths, higher linearity, lower optical loss integrated optical modulators on chip. In this paper, we review existing integration strategies of III–V materials and present a route towards hybrid integration of both III–V and ferroelectrics on the same chip. We show that adiabatic transformation of the optical mode between hybrid ferroelectric and silicon sections enables efficient transfer of optical modal energies for maximum overlap of the optical mode with the ferroelectric media, similar to approaches adopted to maximize optical overlap with the gain section, thereby reducing lasing thresholds for hybrid III–V integration with silicon PICs. Preliminary designs are presented to enable a foundry compatible hybrid integration route of diverse functionalities on silicon PICs.
  • Jun. 17, 2021
  • Journal of Semiconductors
  • Vol.42 Issue, 4 041303 (2021)
  • DOI:10.1088/1674-4926/42/4/041303