49 results on '"Yixin, Wang"'
Search Results
2. An Asymmetric-Error-Aware LDPC Decoding Algorithm for DNA Storage
- Author
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Yi Sun, Guojun Han, Chang Liu, Yixin Wang, and Yi Fang
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Modeling and Simulation ,Electrical and Electronic Engineering ,Computer Science Applications - Published
- 2023
3. Modelling, Characterization of Data-Dependent and Process-Dependent Errors in DNA Data Storage
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Chueh Loo Poh, Yixin Wang, Noor-A-Rahim, Erry Gunawan, and Yong Liang Guan
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Sequence ,business.industry ,Computer science ,DNA digital data storage ,Applied Mathematics ,Process (computing) ,Data recovery ,Characterization (materials science) ,Computer data storage ,Genetics ,business ,Algorithm ,Decoding methods ,Communication channel ,Biotechnology - Abstract
MotivationUsing DNA as the medium to store information has recently been recognized as a promising solution for long-term data storage. While several system prototypes have been demonstrated, the error characteristics in DNA data storage are discussed with limited content. Due to the data and process variations from experiment to experiment, the error variation and its effect on data recovery remain to be uncovered. To close the gap, we systematically investigate the storage channel, i.e., error characteristics in the storage process.ResultsWe first propose a new concept named sequence corruption to unify the error characteristics into the sequence level, easing the channel analysis. Then we derived the formulations of the data imperfection at the decoder including both sequence loss and sequence corruption, revealing the decoding demand and monitoring the data recovery. Furthermore, we extensively explored several data-dependent unevenness observed in the base error patterns and studied a few potential factors and their impacts on the data imperfection at the decoder both theoretically and experimentally. The results presented here introduce a more comprehensive channel model and offer a new angle towards the data recovery issue in DNA data storage by further elucidating the error characteristics of the storage process.Contactpoh.chuehloo@nus.edu.sg
- Published
- 2023
4. Addressing Hindsight Bias in Multigoal Reinforcement Learning
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Lingxiao Wang, Peng Liu, Chenjia Bai, Zhaoran Wang, Chenyao Bai, Yixin Wang, and Rui Zhao
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Computer science ,business.industry ,Efficient algorithm ,Robotics ,Computer Science Applications ,Human-Computer Interaction ,Control and Systems Engineering ,Key (cryptography) ,Reinforcement learning ,Artificial intelligence ,Electrical and Electronic Engineering ,business ,Software ,Hindsight bias ,Information Systems - Abstract
Multigoal reinforcement learning (RL) extends the typical RL with goal-conditional value functions and policies. One efficient multigoal RL algorithm is the hindsight experience replay (HER). By treating a hindsight goal from failed experiences as the original goal, HER enables the agent to receive rewards frequently. However, a key assumption of HER is that the hindsight goals do not change the likelihood of the sampled transitions and trajectories used in training, which is not the fact according to our analysis. More specifically, we show that using hindsight goals changes such a likelihood and results in a biased learning objective for multigoal RL. We analyze the hindsight bias due to this use of hindsight goals and propose the bias-corrected HER (BHER), an efficient algorithm that corrects the hindsight bias in training. We further show that BHER outperforms several state-of-the-art multigoal RL approaches in challenging robotics tasks.
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- 2023
5. Anti-Interference From Noisy Labels: Mean-Teacher-Assisted Confident Learning for Medical Image Segmentation
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Zhe Xu, Donghuan Lu, Jie Luo, Yixin Wang, Jiangpeng Yan, Kai Ma, Yefeng Zheng, and Raymond Kai-Yu Tong
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Radiological and Ultrasound Technology ,Electrical and Electronic Engineering ,Software ,Computer Science Applications - Abstract
Manually segmenting medical images is expertise-demanding, time-consuming and laborious. Acquiring massive high-quality labeled data from experts is often infeasible. Unfortunately, without sufficient high-quality pixel-level labels, the usual data-driven learning-based segmentation methods often struggle with deficient training. As a result, we are often forced to collect additional labeled data from multiple sources with varying label qualities. However, directly introducing additional data with low-quality noisy labels may mislead the network training and undesirably offset the efficacy provided by those high-quality labels. To address this issue, we propose a Mean-Teacher-assisted Confident Learning (MTCL) framework constructed by a teacher-student architecture and a label self-denoising process to robustly learn segmentation from a small set of high-quality labeled data and plentiful low-quality noisy labeled data. Particularly, such a synergistic framework is capable of simultaneously and robustly exploiting (i) the additional dark knowledge inside the images of low-quality labeled set via perturbation-based unsupervised consistency, and (ii) the productive information of their low-quality noisy labels via explicit label refinement. Comprehensive experiments on left atrium segmentation with simulated noisy labels and hepatic and retinal vessel segmentation with real-world noisy labels demonstrate the superior segmentation performance of our approach as well as its effectiveness on label denoising.
- Published
- 2022
6. Multi-Modal Domain Adaptation Variational Autoencoder for EEG-Based Emotion Recognition
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Yixin Wang, Shuang Qiu, Dan Li, Changde Du, Bao-Liang Lu, and Huiguang He
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Control and Optimization ,Artificial Intelligence ,Control and Systems Engineering ,Information Systems - Published
- 2022
7. Incorporating Uncertainty Into Path Planning for Minimally Invasive Robotic Neurosurgery
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William M. Wells, Nazim Haouchine, Yixin Wang, Jie Luo, Steve Pieper, Alexandra J. Golby, and Sarah F. Frisken
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medicine.medical_specialty ,Computer science ,medicine ,Operations management ,Neurosurgery ,Motion planning - Published
- 2022
8. 3-D Least-Squares Reverse Time Migration in Curvilinear-τ Domain
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Huang Chongpeng, Ren Jingru, Yixin Wang, Chang Liu, Zhenchun Li, and Yingming Qu
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Curvilinear coordinates ,Mathematical analysis ,Seismic migration ,General Earth and Planetary Sciences ,Electrical and Electronic Engineering ,Least squares ,Domain (software engineering) ,Mathematics - Published
- 2022
9. Impact of Quantum Dots on III-Nitride Lasers: A Theoretical Calculation on Linewidth Enhancement Factors
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Fang Liu, Jiajia Yang, Xin Rong, Liuyun Yang, Tao Wang, Susu Yang, Zhen Huang, Tai Li, Xinqiang Wang, Renchun Tao, Bo Shen, Yixin Wang, Yasuhiko Arakawa, and Bowen Sheng
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Materials science ,business.industry ,Laser ,Atomic and Molecular Physics, and Optics ,Semiconductor laser theory ,law.invention ,Laser linewidth ,Semiconductor ,Quantum dot ,Quantum dot laser ,law ,Density of states ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Quantum well - Abstract
III-nitride quantum dot (QD) lasers have potential applications in visible light regime, yet one of its most important dynamic parameters, the linewidth enhancement factor (LEF), has been rarely studied. We studied the LEF of InGaN QD lasers with a comprehensive theory model and found that the LEF values of InGaN QD lasers can be smaller and more robust against inhomogeneous broadening than those of InGaAs QD lasers. In addition, the LEF improvement from quantum well to QD in III-nitride semiconductors is much larger than that in III-arsenide. It is believed that the large confinement energy in III-nitrides and atomic-like density of states of QDs contribute to these advantages of III-nitride QD lasers. Our results not only reveal the advantages of using III-nitride QD for high spectral purity, low-chirp laser applications, but also provide a general guideline for designing QD lasers with lower LEF values in various semiconductor materials.
- Published
- 2022
10. SSA-Net: Spatial Scale Attention Network for Image-Based Geo-Localization
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Xiangchuang Meng, Yinghui Xing, Yanning Zhang, Yixin Wang, Hanlin Yin, Yuanzeng Yue, and Xiuwei Zhang
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Matching (statistics) ,business.industry ,Computer science ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Pattern recognition ,Geotechnical Engineering and Engineering Geology ,Visual appearance ,Discriminative model ,Salience (neuroscience) ,Feature (computer vision) ,Benchmark (computing) ,RGB color model ,Artificial intelligence ,Electrical and Electronic Engineering ,business ,Representation (mathematics) - Abstract
Image based Geo-localization is estimating the location of a query image by matching it to a large amount of images in Geo-tagged database. This matching task is very challenging due to the vast differences in visual appearance or modality of image pairs on different platforms, e.g., one image from the RGB camera, the other from the light detection and ranging (LIDAR) sensor. The spatial layout of the scene can provide important clues and significantly reduce matching ambiguity. Therefore, we propose a novel deep network that embeds spatial configuration of the scenes into feature representation. Specifically, we design a spatial-scale attention (SSA) module to highlight the salience correspondence layout features at different scales. The encoded features not only represent the emergence of certain objects, but also reflect the relative locations of the objects. By this way, we learn more discriminative deep feature representations, leading to a higher recall. The experimental results on two standard cross-view benchmark datasets (CVUSA and CVACT) and a cross-modal dataset (GRAL) demonstrate that our method performs better than the state-of-the-art methods. Remarkably, the recall rate@top-1 improves from 27.6% in [1] to 40.5% on the GRAL dataset.
- Published
- 2022
11. A Data-Driven Method for Online Monitoring Tube Wall Thinning Process in Dynamic Noisy Environment
- Author
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Emily Jianzhong Hao, Jun Long Lim, Jiliang Eugene Phua, Yixin Wang, Chen Zhang, Aayush Madan, Keng Boon Siah, Wenyu Jiang, Ouyang Liu, Kai Wu, Karan M. Sabnani, Shili Xiang, Rebecca Yen-Ni Wong, Yongwei Zhu, and Steven C. H. Hoi
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Fiber Bragg grating ,Control and Systems Engineering ,Computer science ,Acoustics ,Feature extraction ,Process (computing) ,Internal erosion ,Tube (fluid conveyance) ,Electrical and Electronic Engineering ,Focus (optics) ,Signal ,Data-driven - Abstract
Tube internal erosion, which corresponds to its wall thinning process, is one of the major safety concerns for tubes. Many sensing technologies have been developed to detect a tube wall thinning process. Among them, fiber Bragg grating (FBG) sensors are the most popular ones due to their precise measurement properties. Most of the current works focus on how to design different types of FBG sensors according to certain physical laws and only test their sensors in controlled laboratory conditions. However, in practice, an industrial system usually suffers from harsh and dynamic environmental conditions, and FBG signals are affected by many unpredictable factors. Consequently, the FBG signals have more fluctuations and are polluted by noises. Hence, the signals no longer directly follow the assumed physical laws and their proposed thinning detection mechanisms no longer work. Targeting at this, this article develops a data-driven model for FBG signal feature extraction and tube wall thickness monitoring using data analytic techniques. In particular, we develop a spatiotemporal model to describe dynamic FBG signals and extract features related to thickness. By taking physical law as guideline, we trace the relationship between the extracted features and the tube wall thickness, based on which we construct an online statistical monitoring scheme for tube wall thinning process. We use both laboratory test and field trial experiment to demonstrate the efficacy and efficiency of the proposed scheme.
- Published
- 2022
12. A Vertically Aligned Multiwall Carbon Nanotube-Based Humidity Sensor With Fast Response, Low Hysteresis, and High Repeatability
- Author
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Xiaoyi Wang, Yixin Wang, Yang Deng, Wei Xu, Xingru Chen, Hongyu Yu, and Zichao Ma
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Interconnection ,Resistive touchscreen ,Materials science ,Fabrication ,business.industry ,Humidity ,Linearity ,Carbon nanotube ,law.invention ,Hysteresis ,law ,Optoelectronics ,Surface modification ,Electrical and Electronic Engineering ,business ,Instrumentation - Abstract
We present a vertically aligned multiwall carbon nanotube (VA-MWCNT) based humidity sensor with low cost and simple fabrication method compatible with mass production. The VA-MWCNT is well aligned and possesses an interconnect topography. Initially, the VA-MWCNT showed superhydrophobic characteristics, which are not suitable for humidity sensing. Therefore, to protect the topography of the material and make the surface more hydrophilic, a low cost and easy handling treatment method was adopted with O2 plasma surface functionalization. The fabricated device showed good linearity at the range of 40% RH–90% RH, low hysteresis ( H = 1.5%RH), fast response (3.3 s), high stability ( Cv Rr _max 0.6% ), demonstrating excellent performance in both static and dynamic measurements. The high performance and low-cost fabrication methods make the VA-MWCNT-based sensor a promising candidate for the application of humidity sensing. Moreover, benefiting from the simple fabrication process, it can be easily extended to resistive sensing fusion with the integration of the temperature sensor and flow sensor for more complex applications.
- Published
- 2021
13. Domain Adaptation for EEG Emotion Recognition Based on Latent Representation Similarity
- Author
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Jinpeng Li, Changde Du, Huiguang He, Shuang Qiu, and Yixin Wang
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Artificial neural network ,Computer science ,business.industry ,Generalization ,Feature extraction ,Pattern recognition ,02 engineering and technology ,Conditional probability distribution ,010501 environmental sciences ,01 natural sciences ,ComputingMethodologies_PATTERNRECOGNITION ,Artificial Intelligence ,Joint probability distribution ,Similarity (psychology) ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Artificial intelligence ,Marginal distribution ,Association (psychology) ,business ,Software ,0105 earth and related environmental sciences - Abstract
Emotion recognition has many potential applications in the real world. Among the many emotion recognition methods, electroencephalogram (EEG) shows advantage in reliability and accuracy. However, the individual differences of EEG limit the generalization of emotion classifiers across subjects. Moreover, due to the nonstationary characteristic of EEG, the signals of one subject change over time, which is a challenge to acquire models that could work across sessions. In this article, we propose a novel domain adaptation method to generalize the emotion recognition models across subjects and sessions. We use neural networks to implement the emotion recognition models, which are optimized by minimizing the classification error on the source while making the source and the target similar in their latent representations. Considering the functional differences of the network layers, we use adversarial training to adapt the marginal distributions in the early layers and perform association reinforcement to adapt the conditional distributions in the last layers. In this way, we approximately adapt the joint distributions by simultaneously adapting marginal distributions and conditional distributions. The method is compared with multiple representatives and recent domain adaptation algorithms on benchmark SEED and DEAP for recognizing three and four affective states, respectively. The experimental results show that the proposed method reaches and outperforms the state of the arts.
- Published
- 2020
14. MVCLN: Multi-View Convolutional LSTM Network for Cross-Media 3D Shape Recognition
- Author
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Yixin Wang, Qiang Li, Qi Liang, and Weizhi Nie
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3D model ,General Computer Science ,Computer science ,02 engineering and technology ,Machine learning ,computer.software_genre ,01 natural sciences ,Task (project management) ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,Set (psychology) ,retrieval ,Spatial analysis ,Structure (mathematical logic) ,Landmark ,business.industry ,Deep learning ,010401 analytical chemistry ,General Engineering ,020206 networking & telecommunications ,Construct (python library) ,0104 chemical sciences ,Convolutional LSTM ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,Artificial intelligence ,recognition ,Focus (optics) ,business ,lcsh:TK1-9971 ,computer - Abstract
Cross-media 3D model recognition is an important and challenging task in computer vision, which can be utilized in many applications such as landmark detection, image set classification, etc. In recent years, with the development of deep learning, many approaches have been proposed to handle the 3D model recognition problem. However, all of these methods focus on the structure information representation and the multi-view information fusion, and ignore the spatial and temporal information. So that it is not suitable for the cross-media 3D model recognition. In this paper, we utilize the sequence views to represent each 3D model and propose a novel Multi-view Convolutional LSTM Network (MVCLN), which utilizes the LSTM structure to extract temporal information and applies the convolutional operation to extract spatial information. More especially, the spatial and temporal information both are considered during the training process, which can effectively utilize the differences between the view's spatial information to improve the final performance. Meanwhile, we also introduce the classic attention model to define the weight of each view, which can reduce the redundant information of view's spatial information in the information fusion step. We evaluate the proposed method on the ModelNet40 for 3D model classification and retrieval task. We also construct a dataset utilizing the overlap categories of MV-RED, ShapenetCore and ModelNet to demonstrate the effectiveness of our approach for the cross-media 3D model recognition. Experimental results and comparisons with the state-of-the-art methods demonstrate that our framework can achieve superior performance.
- Published
- 2020
15. Adaptive Strategy of General Centralized Feedback Model for Interference Alignment in Asymmetric Interference Networks
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Tingpei Huang, Shibao Li, Jianhang Liu, Wei Ye, Zhao Dayin, and Yixin Wang
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Computer science ,020302 automobile design & engineering ,020206 networking & telecommunications ,Topology (electrical circuits) ,Throughput ,02 engineering and technology ,Function (mathematics) ,Interference (wave propagation) ,Network topology ,Upper and lower bounds ,0203 mechanical engineering ,Control theory ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,Realization (systems) ,Decoding methods ,Interference alignment ,Computer Science::Information Theory - Abstract
Interference alignment (IA) is a promising technique to effectively manage the interference. The realization of IA requires a proliferation of feedback bits. In a general centralized feedback model, the feedback rate of the precoder and the decoder affects the performance of the IA directly. In this paper, to improve the feedback efficiency of the precoder and the decoder, a strategy that can adaptively allocate the feedback bits of the precoder and the decoder is proposed. We consider the effect of link loss on the throughput loss caused by the quantization error of the precoder and decoder. An upper bound of leaked interference as a function of the link loss and the feedback bits of the precoders and the decoders is derived. The feasibility conditions for dynamically allocating the feedback bits of the precoder and the decoder are analyzed. It is proven that the properties of general asymmetric interference network can satisfy the feasibility conditions for dynamic feedback scheme. According to the simulation results, our proposed scheme achieves higher throughput compared with the conventional schemes in the asymmetric interference network.
- Published
- 2019
16. Modal Excitations in Fully and Partially Ethanol-Filled Photonic Bandgap Fibers and Their Applications as Fiber Sensors
- Author
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Zhanyu Shen, Changyuan Yu, Bo Dong, and Yixin Wang
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Materials science ,business.industry ,Single-mode optical fiber ,02 engineering and technology ,Cladding (fiber optics) ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,010309 optics ,020210 optoelectronics & photonics ,Modal ,Optics ,Fiber optic sensor ,0103 physical sciences ,Thermal ,0202 electrical engineering, electronic engineering, information engineering ,Astronomical interferometer ,Optoelectronics ,Spatial frequency ,business ,Photonic-crystal fiber - Abstract
The light guidance characteristics of the fully and partially ethanol-filled photonic bandgap fibers (PBFs) are investigated and their applications as modal interferometers (MIs) for temperature sensing are demonstrated. Different from the ethanol-filled solid core photonic crystal fibers (PCFs), the ethanol-filled PBFs are much easier to excite more high order cladding modes, and the effective refractive index difference between the interference modes can reach 26.6 times bigger than that of the ethanol-filled solid core PCF. Without using special splicing techniques, just splicing a short section of the fully or partially ethanol-filled PBF between the single mode fibers, a PBG-based MI can be constructed with a high thermal sensitivity. Moreover, the thermal sensitivity can be adjusted within a large range by selectively filling the air core and/or air claddings of the PBF with ethanol. Experimental results show that the fully ethanol-filled PBF-based MI has the thermal sensitivity up to –292 pm/°C while that of the partially ethanol-filled PBF-based MI is changed to –120 pm/°C. They are 43.8 and 18 times bigger than that of the unfilled PBF-based MI.
- Published
- 2016
17. Mode Division Multiplexing in a Fiber Modal Interferometer for Dual-Parameters Measurement
- Author
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Bo Dong, Changyuan Yu, Yuqi Peng, and Yixin Wang
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Mode volume ,Materials science ,business.industry ,Polarization-maintaining optical fiber ,02 engineering and technology ,Long-period fiber grating ,Cladding (fiber optics) ,Cladding mode ,01 natural sciences ,Graded-index fiber ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,010309 optics ,020210 optoelectronics & photonics ,Optics ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Dispersion-shifted fiber ,Electrical and Electronic Engineering ,business ,Plastic optical fiber - Abstract
We propose a novel scheme for simultaneous strain and temperature measurement by mode division multiplexing (MDM) in a dual cladding modes fiber up-taper interferometer. The fiber interferometer, with a strong cladding mode and a weak cladding mode, can be constructed by fabricating two optimized adjacent fiber up-tapers along a single-mode fiber. With the MDM method, the temperature and strain measurement resolutions reach ±0.05 °C and $\pm 3.14~\mu \varepsilon $ , respectively, which are much higher than those of the other proposed dual-parameters (temperature and strain) measurement solutions.
- Published
- 2016
18. Ultrahigh-Sensitivity Fiber Acoustic Sensor With a Dual Cladding Modes Fiber Up-Taper Interferometer
- Author
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Junhong Ng, Banghong Zhang, Changyuan Yu, Bo Dong, and Yixin Wang
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Materials science ,business.industry ,Polarization-maintaining optical fiber ,Long-period fiber grating ,Cladding (fiber optics) ,Graded-index fiber ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optics ,Double-clad fiber ,Fiber optic sensor ,Dispersion-shifted fiber ,Electrical and Electronic Engineering ,business ,Plastic optical fiber - Abstract
We propose a novel dual cladding modes fiber up-taper interferometer-based surface-mounted acoustic sensor. It consists of two optimized fiber fusion up-tapers along a single-mode fiber that enable it to excite dual cladding modes, which leads to its interference pattern with an extinction ratio of more than 20 dB, guaranteeing it to be used as an intensity-modulated fiber acoustic sensor (FAS) with an ultrahigh sensitivity. Under an acoustic pressure, its simultaneous responses in wavelength shift and intermodal power coupling change contribute to its ultrahigh sensitivity. The sensitivity of the proposed FAS reaches 2.65 V/ $\mu $ Pa and is 33.5 times bigger than that of the piezoelectric acoustic sensor.
- Published
- 2015
19. A Compact and Temperature-Sensitive Directional Coupler Based on Photonic Crystal Fiber Filled With Liquid Crystal 6CHBT
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Karolina Milenko, Tomasz R. Wolinski, Yixin Wang, Jun Long Lim, Ping Shum, Ying Cui, Dora Juan Juan Hu, and School of Electrical and Electronic Engineering
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lcsh:Applied optics. Photonics ,Materials science ,Physics::Optics ,temperature sensor ,law.invention ,Optics ,law ,Liquid crystal ,Phase (matter) ,lcsh:QC350-467 ,selective infiltration ,photonic crystal fiber (PCF) ,Electrical and Electronic Engineering ,Photonic crystal ,business.industry ,Isotropy ,lcsh:TA1501-1820 ,Atomic and Molecular Physics, and Optics ,Nematic liquid crystal (NLC) ,Engineering::Electrical and electronic engineering [DRNTU] ,Power dividers and directional couplers ,Optoelectronics ,business ,Waveguide ,Refractive index ,lcsh:Optics. Light ,Photonic-crystal fiber - Abstract
A directional coupler structure formed by a nematic liquid crystal (NLC)-filled photonic crystal fiber (PCF) represents a promising configuration in sensing applications. Because of large refractive index difference between the NLC and silica material, the mode coupling between the NLC waveguide and the silica core is more complicated than the situation of coupling between two fundamental modes of the waveguides. Therefore, it is necessary to perform a theoretical investigation of the mode properties associated with the experimental studies of the coupling characteristics. In this paper, we present a thorough analysis, both theoretically and experimentally, of the directional coupler structure, including the mode properties, coupling characteristics, and thermal sensing properties. The temperature response of the device is experimentally measured, showing a polynomial curve in nematic phase and a linear curve in isotropic phase. The nonlinearity of the temperature response of the device in nematic phase and the linearity in isotropic phase are attributed to the temperature dependence of the refractive index of the NLC. Specifically, the sensitivity is -3.86 nm/°C in isotropic phase of the 6CHBT with good linearity and shows good agreement with simulation results.
- Published
- 2012
20. Fabrication and Characterization of a Highly Temperature Sensitive Device Based on Nematic Liquid Crystal-Filled Photonic Crystal Fiber
- Author
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Ping Shum, Dora Juan Juan Hu, Karolina Milenko, Ying Cui, Tomasz R. Wolinski, Yixin Wang, Jun Long Lim, and School of Electrical and Electronic Engineering
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lcsh:Applied optics. Photonics ,Void (astronomy) ,Materials science ,Fabrication ,business.industry ,lcsh:TA1501-1820 ,Linearity ,temperature sensor ,Repeatability ,Atmospheric temperature range ,Atomic and Molecular Physics, and Optics ,Nematic liquid crystal (NLC) ,Liquid crystal ,Engineering::Electrical and electronic engineering [DRNTU] ,lcsh:QC350-467 ,Optoelectronics ,selective infiltration ,photonic crystal fiber (PCF) ,Electrical and Electronic Engineering ,business ,lcsh:Optics. Light ,Photonic crystal ,Photonic-crystal fiber - Abstract
We report on the fabrication and characterization of a highly sensitive temperature sensor by selectively filling the nematic liquid crystal (NLC) 6CHBT into a single void within the photonic crystal fiber (PCF) structure. The temperature response of the device is experimentally characterized, showing good linearity, repeatability, and sensitivity at around -3.90 nm/°C within the temperature range from 44°C to 53°C. The mode properties of the device are theoretically investigated, confirming the mode coupling principle and the temperature sensitivity of the device.
- Published
- 2012
21. Photonic Crystal Fiber-Based Interferometric Biosensor for Streptavidin and Biotin Detection
- Author
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Mi Kyoung Park, Huifeng Wei, Dora Juan Juan Hu, Yixin Wang, Weijun Tong, Jun Long Lim, and Linus Tzu-Hsiang Kao
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Streptavidin ,Optical fiber ,Materials science ,business.industry ,Polarization-maintaining optical fiber ,Microstructured optical fiber ,Cladding (fiber optics) ,Atomic and Molecular Physics, and Optics ,law.invention ,chemistry.chemical_compound ,Optics ,chemistry ,law ,Optoelectronics ,Electrical and Electronic Engineering ,Plastic optical fiber ,business ,Photonic crystal ,Photonic-crystal fiber - Abstract
We report the fabrication of a highly sensitive refractometer based on photonic crystal fiber (PCF) interferometry. Using fusion arc splicing technique, a short length of PCF (∼3 mm) was spliced to conventional single-mode fibers on both sides. The voids of the PCF were completely collapsed in the splice region, which acted as mode splitter and combiner on both sides. Microbubbles were formed in the splice region and acted as diverging lens for exciting cladding modes efficiently. The transmission spectrum exhibited detectable “dips” for refractive index (RI) sensing. The bulk liquid sensitivity can reach up to 320 nm/RIU (RI unit) based on the linear curve fit for RI ranging from 1.33 to 1.34. Biosensing experiment was carried out using streptavidin and biotin as respective analyte and receptor. To the best of authors’ knowledge, this is the first time of reporting bioaffinity test on the external surface of PCF using modal interferometry.
- Published
- 2012
22. Characteristics of Subcarrier Modulation and Its Application in WDM-PONs
- Author
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Yang Jing Wen, Yong-Kee Yeo, Xiaofei Cheng, Zhaowen Xu, Tee Hiang Cheng, Chao Lu, Yixin Wang, Wen-De Zhong, and M. Attygalle
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Physics ,Optical amplifier ,Modulation ,Optical Carrier transmission rates ,Subcarrier multiplexing ,Wavelength-division multiplexing ,Baseband ,Electronic engineering ,Electro-optic modulator ,Atomic and Molecular Physics, and Optics ,Subcarrier - Abstract
We mathematically analyze and experimentally investigate the characteristics of subcarrier-modulated (SCM) light. Our investigation shows that the baseband data are also carried on the optical carrier after subcarrier modulation. This residual data introduce crosstalk when the optical carrier is separated from subcarriers and reused for uplink data modulation. The influence of the residual data carried on the optical carrier is studied in three kinds of upstream transmissions based on wavelength-seeded reflective semiconductor optical amplifiers (RSOAs) for carrier-reuse wavelength-division-multiplexed-passive optical networks (WDM-PONs). Results show that the crosstalk can be significantly suppressed with proper selection of the seeding power and operation conditions of downlink Mach-Zehnder modulator (MZM), including driving voltage and bias voltage.
- Published
- 2009
23. Stimulate Brillouin Scattering Based Broadband Tunable Slow-Light Conversion in a Highly Nonlinear Photonic Crystal Fiber
- Author
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Tee Hiang Cheng, Weifeng Rong, Yixin Wang, Luying Zhou, Jianguo Liu, Yong-Kee Yeo, Xiaojun Yu, Gaoxi Xiao, Lifang Xue, and Dawei Wang
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Optical fiber ,Materials science ,business.industry ,Nonlinear optics ,Slow light ,Atomic and Molecular Physics, and Optics ,law.invention ,Four-wave mixing ,Optics ,law ,Brillouin scattering ,Nonlinear photonic crystal ,business ,Photonic-crystal fiber ,Photonic crystal - Abstract
An integrated configuration is proposed to convert tunable slow light from signal to another frequency in a wide bandwidth by using a 70 m-long highly nonlinear photonic crystal fiber (HN-PCF). A 10 GHz RZ signal is delayed by a 10 Gbit/s 231-1 pseudo random bit sequence (PRBS) stimulated Brillouin scattering (SBS) pump, and the slow light is converted to another frequency in a broadband by four-wave mixing (FWM). By this way, not only the slow light is converted, but the idler power is enhanced greatly. In our experiment, all-optical controlled 37.5 ps delay time is converted in a 40 nm bandwidth flatly, and 4.7 dB idler power is enhanced simultaneously. The experimental results are in good agreement with those of the theory.
- Published
- 2009
24. WDM-PON Architectures With a Single Shared Interferometric Filter for Carrier-Reuse Upstream Transmission
- Author
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Zhaowen Xu, Xiaofei Cheng, Wen-De Zhong, M. Attygalle, Chao Lu, Yixin Wang, Tee Hiang Cheng, and Yang Jing Wen
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Optical amplifier ,Engineering ,Transmission (telecommunications) ,business.industry ,Filter (video) ,Wavelength-division multiplexing ,Electronic engineering ,Baseband ,Upstream (networking) ,business ,Passive optical network ,Atomic and Molecular Physics, and Optics ,Subcarrier - Abstract
We propose two novel wavelength-division-multiplexed passive-optical-network (WDM-PON) architectures where subcarriers are employed to transmit downstream data and optical carriers are reused for upstream transmission. Architecture I is designed for the situation where two short distribution fibers are available between the remote node (RN) and each optical network unit (ONU), whereas Architecture II is devised for the case where there is only one distribution fiber between the RN and each ONU. Both architectures use only one interferometric filter located at the RN to simultaneously separate all downlink optical carriers and subcarriers, leading to a considerable cost reduction in the implementation of the WDM-PONs. Separated optical carriers are then reused and injected into reflective semiconductor optical amplifiers as the uplink light sources, which eliminates the necessity of specific wavelength sources at the ONUs. The downstream subcarrier signals are directly detected using baseband receivers. Two multichannel upstream and downstream transmission experiments are carried out at 1.25 Gb/s using the proposed schemes. The impact of optical carrier-to-subcarrier ratio of downlink signal, Rayleigh-backscattering noise, and wavelength mismatch between laser source and filter on system performance is also investigated.
- Published
- 2007
25. Externally Modulated Optical Minimum Shift Keying Format
- Author
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Yang Jing Wen, Jinyu Mo, Chao Lu, Yixin Wang, and Wen-De Zhong
- Subjects
Physics ,Optical fiber ,business.industry ,Single-mode optical fiber ,Optical communication ,Minimum-shift keying ,Atomic and Molecular Physics, and Optics ,Amplitude-shift keying ,law.invention ,Optics ,law ,Wavelength-division multiplexing ,business ,Self-phase modulation ,Optical filter - Abstract
This paper presents the generation and the performance evaluation of optical minimum shift keying (MSK) for high-speed and high-spectral-efficiency wavelength-division multiplexing systems. The detailed principle on optical MSK generation and detection is derived and analyzed. Optical MSK data (10.7 Gb/s) are successfully generated by an experiment using the proposed scheme. The results show that the optical MSK signal exhibits a very compact optical spectrum. The performance of the optical MSK modulated system is evaluated and compared with those of 50% duty-cycle return-to-zero differential phase shift keying (RZ-DPSK) and 50% duty-cycle return-to-zero on-off keying (RZ-OOK) modulated systems, via both simulation and experiment, in terms of dispersion tolerance, linear crosstalk, self-phase modulation (SPM) tolerance, stimulated Brillouin scattering (SBS) threshold, optimal receiver filter bandwidth, and optimal link launch power into single-mode fibers and dispersion compensation fibers. Experimental and simulation results show that the MSK signal exhibits the largest tolerance against fiber dispersion and SPM effect as compared with RZ-DPSK and RZ-OOK. Experimental results also confirm the negative penalty against the SPM effect. The SBS threshold of both the MSK and RZ-DPSK systems is more than 10 dB higher than that of the RZ-OOK system. The MSK that is generated with conventional carrier-suppressed return-to-zero (CSRZ) pulses exhibits a narrower optimal optical filter bandwidth but a wider electrical filter bandwidth compared with those of RZ-OOK and RZ-DPSK. The MSK signal that is generated with pure dual-mode pulses has a similar optimum range to RZ-OOK and RZ-DPSK at a high optical signal-to-noise ratio (OSNR) but has a narrower optimal optical filter bandwidth at a low OSNR. The optimum fiber launch power study shows that the MSK signal that is generated using the conventional CSRZ pulses exhibits higher optimum launch power, which agrees with the SPM tolerance study.
- Published
- 2007
26. WDM optical network testbed and distributed storage application
- Author
-
Victor Foo, Jit Biswas, Luying Zhou, Chao Lu, Yixin Wang, Chava Vijaya Saradhi, Teck Yoong Chai, and Qiu Qiang
- Subjects
Multiwavelength optical networking ,Computer Networks and Communications ,business.industry ,Computer science ,computer.internet_protocol ,Optical cross-connect ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,Multiprotocol Label Switching ,Optical performance monitoring ,Optical burst switching ,Passive optical network ,Computer Science Applications ,Storage area network ,Optical Transport Network ,Backup ,Wavelength-division multiplexing ,Distributed data store ,Electrical and Electronic Engineering ,Routing control plane ,business ,computer ,Optical add-drop multiplexer ,Computer network - Abstract
In this article we present the details of a generalized multiprotocol label switching controlled wavelength-division multiplexing (WDM) optical network developed under the Optical Network Focused Interest Group (ONFIG) program in Singapore. The WDM network is controlled through a GMPLS control plane that consists of CR-LDP, LMP, and OSPF-TE. We conducted various field trials on the GMPLS-capable WDM optical network testbed with the main focus on distributed storage service application. We developed and evaluated a distributed storage services application on the WDM optical network testbed and demonstrated that incorporating a lightweight data transport protocol with optical network control could be an efficient approach for data-intensive storage applications by exploiting the dynamic connection establishment and backup protection features.
- Published
- 2006
27. Design of multistage gain-flattened fiber Raman amplifiers
- Author
-
Jian Chen, Xueming Liu, Chao Lu, Yixin Wang, and Zhaohui Li
- Subjects
Optical amplifier ,Engineering ,Optical fiber ,business.industry ,Amplifier ,Single-mode optical fiber ,Distributed amplifier ,Noise figure ,Atomic and Molecular Physics, and Optics ,law.invention ,Optics ,law ,Net gain ,Electronic engineering ,Multistage amplifier ,business - Abstract
This paper presents a design approach for multistage gain-flattened fiber Raman amplifiers (FRAs) utilizing the multiwavelength-pumping scheme. To the authors' best knowledge, it is the first time that Raman amplifiers of more than one stage are considered in the design process so as to optimize multistage amplifier performance simultaneously. It is shown both theoretically and experimentally that optical power path integrals among several stages can, in principle, be arbitrarily redistributed while maintaining its gain performance, as long as the consolidated sums at different pump wavelengths are unaltered. The overall gain spectrum of a multistage FRA is thus very close to the cumulative spectrum of chained identical single-stage amplifiers with span numbers equal to its stages. However, the traditional prerequisite to minimize gain flatness in every stage is no longer required. It provides flexibilities to take full advantage of pump lasers with moderate launched powers and allows the reduction of the number of pump lasers and/or wavelengths in most stages. By arranging small positive net gain to the first stages and enhancing it at shorter signal wavelengths, significant reduction and flattening of total noise figure (NF) is achieved even if a pure backward pumping scheme is utilized. Finally, various pumping configurations for Raman amplifiers with hybrid dispersion-compensating fiber (DCF) and standard single-mode fiber (SMF) are discussed, with the objective of realizing flattened gain and noise performance simultaneously without using forward pumps.
- Published
- 2006
28. Pump-Suppressed Nondegenerate Four-Wave Mixing in a Highly Nonlinear Photonic Crystal Fiber Sagnac Loop
- Author
-
Gaoxi Xiao, Jianguo Liu, Tee Hiang Cheng, Xiaojun Yu, Dawei Wang, Luying Zhou, Yixin Wang, Lifang Xue, Yong-Kee Yeo, and Weifeng Rong
- Subjects
Physics ,business.industry ,Bandwidth (signal processing) ,Energy conversion efficiency ,Physics::Optics ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optical pumping ,Four-wave mixing ,Wavelength ,Optics ,Nonlinear photonic crystal ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Photonic crystal ,Photonic-crystal fiber - Abstract
We propose a configuration for suppressing pumps in a broad-and flat-band tunable nondegenerate four-wave mixing (FWM) wavelength converter. The signal and pumps are coupled into a highly nonlinear photonic crystal fiber symmetrical Sagnac loop. After the FWM wavelength conversion in the loop, the idler is separated from the pumps without a filter. In our experiment, a flat wavelength conversion bandwidth of 36 nm, conversion efficiency of -11 dB, pump-to-signal suppression ratio of 48 dB, and idler-to-pump suppression ratio of 15 dB are achieved.
- Published
- 2008
29. An on–off-Keying Optical Receiver With Dual Thresholds and Erasure Zone
- Author
-
Yong Liang Guan, Jian Chen, Bing Xie, and Yixin Wang
- Subjects
Computer science ,On-off keying ,Bit error rate ,Electronic engineering ,Erasure ,Forward error correction ,Code rate ,Electrical and Electronic Engineering ,Atomic and Molecular Physics, and Optics ,Amplitude-shift keying ,Coding gain ,Decoding methods ,Electronic, Optical and Magnetic Materials - Abstract
An ON-OFF-keying optical receiver with dual thresholds and an erasure zone is proposed. This configuration can be applied to track the optimized decision level adaptively and obtain additional coding gain from forward-error correction without increasing the code rate. Our analysis shows that in both unamplified and optically preamplified receivers, the required Q value for the bit-error rate of 10-12 can be reduced by 1.8 dB, if errors arise in burst nature and the optimized erasure zone width is around 7%-11% of the signal swing.
- Published
- 2007
30. Optical Fiber Polarization Interferometer for Performance Improvement in Radio-Over-Fiber Systems
- Author
-
Chao Lu, Yixin Wang, Zhaohui Li, Hao He, Tee Hiang Cheng, Xiangqing Tian, Yi Dong, Qi Jie Wang, and Weisheng Hu
- Subjects
Materials science ,Optical fiber ,Extinction ratio ,business.industry ,Dynamic range ,Physics::Optics ,Polarization-maintaining optical fiber ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Amplitude modulation ,Interferometry ,Optics ,Radio over fiber ,Optical Carrier transmission rates ,law ,Electrical and Electronic Engineering ,business - Abstract
An extinction ratio tunable optical fiber polarization interferometer (OFPI) is proposed and implemented to increase the optical modulation depth in radio-over-fiber (RoF) systems by suppressing the optical carrier power. The extinction ratio of the OFPI can be simply tuned by adjusting the polarization state of the launched RoF signal. Experimental results illustrate that the receiver sensitivity and dynamic range of RoF systems are greatly improved using the proposed scheme.
- Published
- 2007
31. Carrier-Reuse WDM-PON Using a Shared Delay Interferometer for Separating Carriers and Subcarriers
- Author
-
Zhaowen Xu, Chao Lu, Yang Jing Wen, M. Attygalle, Yixin Wang, Xiao Fei Cheng, and Wen-De Zhong
- Subjects
Optical amplifier ,Physics ,genetic structures ,Optical cross-connect ,Optical performance monitoring ,Passive optical network ,eye diseases ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Interferometry ,Wavelength-division multiplexing ,Baseband ,Electronic engineering ,Upstream (networking) ,sense organs ,Electrical and Electronic Engineering - Abstract
We propose a novel optical carrier-reuse scheme for the wavelength-division-multiplexed passive optical network. The scheme is based on a single delay interferometer (DI) at the remote node and reflective semiconductor optical amplifiers (RSOAs) at optical network units as the colorless devices for upstream transmission. The downstream subcarrier signals are optically separated by the DI for baseband detection of the downstream data and the separated optical carriers are used for seeding the RSOAs. Eight-channel upstream and downstream transmission is demonstrated at 1.25 Gb/s using the proposed scheme. The impact of optical carrier-to-subcarrier ratio of downlink signal and seeding light power on performance is also investigated
- Published
- 2007
32. Comparison of Cross-Gain Modulation Effect of Manchester-Duobinary, RZ-DPSK, NRZ-DPSK, RZ, and NRZ Modulation Formats in SOAs
- Author
-
Tee Hiang Cheng, Zhaohui Li, Yi Dong, Chao Lu, Yixin Wang, Yang Jing Wen, and Weisheng Hu
- Subjects
Crosstalk ,Physics ,Optical amplifier ,Optics ,business.industry ,Keying ,Electrical and Electronic Engineering ,Cross gain modulation ,business ,Atomic and Molecular Physics, and Optics ,Amplitude-shift keying ,Electronic, Optical and Magnetic Materials - Abstract
Conventional on-off keyed signals, such as return-to-zero (RZ) and nonreturn-to-zero (NRZ) signals are susceptible to cross-gain modulation (XGM) in semiconductor optical amplifiers (SOAs) due to pattern effect. In this letter, XGM effect of Manchester-duobinary, RZ differential phase-shift keying (RZ-DPSK), NRZ-DPSK, RZ, and NRZ signals in SOAs were compared. The experimental results confirmed the reduction of crosstalk penalty in SOAs by using Manchester-duobinary signals
- Published
- 2006
33. Tunable and Switchable Fiber Ring Laser Among Four Wavelengths With Ultranarrow Wavelength Spacing Using a Quadruple-Transmission-Band Fiber Bragg Grating Filter
- Author
-
Tee Hiang Cheng, Min Yan, Yixin Wang, Li Xia, and Ping Shum
- Subjects
Materials science ,business.industry ,Physics::Optics ,Ring (chemistry) ,Laser ,Optical switch ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Wavelength ,Optics ,Transmission (telecommunications) ,Fiber Bragg grating ,Fiber ring laser ,Filter (video) ,law ,Optoelectronics ,Electrical and Electronic Engineering ,business - Abstract
Four pi-phase shifts are introduced in a uniform fiber Bragg grating (FBG) structure to realize a quadruple-transmission-band filter with ultranarrow 40-pm wavelength spacing. Four separate single-wavelength lasings at 1552.60, 1552.63, 1552.67, and 1552.71 nm, and three pairs of dual-wavelength lasings among above four wavelengths, are achieved stably by incorporating the quadruple-transmission-band FBG filter in a fiber ring cavity with a tunable uniform FBG acting as coarse frequency selection. This new kind of laser will be very useful in applications requiring closely spaced and tunable single- or dual-wavelength components
- Published
- 2006
34. Stable triple-wavelength fiber ring laser with ultranarrow wavelength spacing using a triple-transmission-band fiber Bragg grating filter
- Author
-
Tee Hiang Cheng, Ping Shum, Li Xia, and Yixin Wang
- Subjects
PHOSFOS ,Materials science ,business.industry ,Physics::Optics ,Polarization-maintaining optical fiber ,Long-period fiber grating ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optics ,Fiber Bragg grating ,Fiber laser ,Optoelectronics ,Dispersion-shifted fiber ,Electrical and Electronic Engineering ,business ,Plastic optical fiber ,Photonic-crystal fiber - Abstract
A stable 50-pm-spaced triple-wavelength fiber ring laser with nearly equal output power at each lasing line is achieved experimentally by incorporating a triple-transmission-band fiber Bragg grating filter in the fiber ring cavity. Such a laser will be very useful in applications requiring closely spaced multiwavelength components
- Published
- 2006
35. Optimization of Spectrum-Sliced ASE Source for Injection-Locking a Fabry–PÉrot Laser Diode
- Author
-
Chao Lu, Yixin Wang, Xu Shao, Xiaofei Cheng, Yang Jing Wen, Yi Dong, and Zhaowen Xu
- Subjects
Optical amplifier ,Amplified spontaneous emission ,Materials science ,Laser diode ,business.industry ,Bandwidth (signal processing) ,Superradiance ,Passive optical network ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Injection locking ,Optics ,law ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Fabry–Pérot interferometer - Abstract
We experimentally study the impact of filter bandwidth of a spectrum-sliced amplified spontaneous emission (ASE) source on the injection-locking of a Fabry-Perot laser diode (FPLD) for passive optical network application. Optimal bandwidth of a spectrum-sliced ASE source was found in terms of receiver sensitivity after transmission. We also investigate the impact of intensity noise (IN) of the spectrum-sliced ASE source and its suppression for a wavelength-locked FPLD using a semiconductor optical amplifier. Experiment results show that the output performance of a wavelength-locked FPLD is improved by IN suppression
- Published
- 2006
36. Improving dispersion tolerance of manchester coding by incorporating duobinary coding
- Author
-
Yang Jing Wen, Weisheng Hu, Tee Hiang Cheng, Chao Lu, Yixin Wang, Yi Dong, and Zhaohui Li
- Subjects
Manchester code ,Physics ,Electronic engineering ,Electrical and Electronic Engineering ,Optical modulation amplitude ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Coding (social sciences) - Abstract
A Manchester-duobinary coding scheme is proposed to compact the optical spectrum compared with that using pure Manchester coding and thus demonstrate much larger tolerance against fiber dispersion. With this modulation format, the dispersion tolerance can be extended to nearly three times of that using pure Manchester coding. Dispersion tolerance of Manchester-duobinary is from -800 to +920 ps/nm at 2-dB power penalty
- Published
- 2006
37. PMD and Chirp Effects Suppression in RF Tone-Based Chromatic Dispersion Monitoring
- Author
-
Chao Lu, Yixin Wang, Yang Jing Wen, Ning Liu, Wen-De Zhong, and Linghao Cheng
- Subjects
Pilot signal ,Physics ,business.industry ,Optical performance monitoring ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Tone (musical instrument) ,Optics ,Polarization mode dispersion ,Dispersion (optics) ,Chirp ,Radio frequency ,Electrical and Electronic Engineering ,business ,Pulse-width modulation - Abstract
We investigate the effects of polarization-mode dispersion (PMD) and chirp on radio-frequency tone-based chromatic dispersion (CD) monitoring method, and show that the PMD and chirp induce significant CD monitoring errors. We propose a CD monitoring technique to suppress these effects. Experiment results show that the CD monitoring errors induced by PMD and chirp fluctuation are greatly suppressed.
- Published
- 2006
38. Single-span transmission of WDM RZ-DPSK signal over 310-km standard SMF without using FEC and remote-pumping
- Author
-
Jinyu Mo, Kun Xu, Jian Chen, Yang Jing Wen, Guangtao Zhou, Chao Lu, and Yixin Wang
- Subjects
Raman amplification ,Materials science ,business.industry ,Keying ,Transmission system ,Atomic and Molecular Physics, and Optics ,Amplitude-shift keying ,Electronic, Optical and Magnetic Materials ,Optical pumping ,Optics ,Transmission (telecommunications) ,Brillouin scattering ,Wavelength-division multiplexing ,Electrical and Electronic Engineering ,business - Abstract
To avoid significant stimulated Brillouin scattering (SBS) generation in a bidirectional Raman-pumped long single-span transmission system, the SBS threshold is studied in both return-to-zero on-off -keying (RZ-OOK) and RZ differential phase-shift keying (DPSK) systems. It shows that SBS threshold in an RZ-DPSK system is more than 10 dB higher than that in an RZ-OOK system, and SBS reflection is dominated by copumping, while counterpumping has minor effect. Error-free eight-channel single-span transmission is demonstrated over 310-km standard single-mode fiber using RZ-DPSK format and bidirectional Raman pumping, without applying forward-error correction and remote-pumping techniques.
- Published
- 2005
39. In-service signal quality monitoring and multi-impairment discrimination based on asynchronous amplitude histogram evaluation for NRZ-DPSK systems
- Author
-
Guifang Li, Zhihong Li, Chao Lu, and Yixin Wang
- Subjects
Physics ,Amplified spontaneous emission ,business.industry ,Gaussian ,Optical performance monitoring ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Amplitude modulation ,symbols.namesake ,Optics ,Modulation ,Dispersion (optics) ,symbols ,Adaptive histogram equalization ,Electrical and Electronic Engineering ,business ,Algorithm ,Phase modulation - Abstract
A novel in-service signal quality monitoring technique for nonreturn-to-zero differential phase-shift keying signals using asynchronous amplitude histogram evaluation has been demonstrated. As a result of phase-to-amplitude modulation, there are three Gaussian distributions in the amplitude histogram. The widths of the Gaussian distributions are related to the amount of amplified spontaneous emission, while the separations between the Gaussian distributions increase monotonically with fiber dispersion. The amount of dispersion and optical signal-to-noise ratio can, thus, be directly extracted and discriminated from the amplitude histogram.
- Published
- 2005
40. A novel PSK-manchester Modulation format in 10-gb/s passive optical network system with high tolerance to beat interference noise
- Author
-
Chao Lu, Yixin Wang, Zhihong Li, and Yi Dong
- Subjects
Optical amplifier ,Computer science ,Wavelength-division multiplexing ,Electronic engineering ,Optical noise ,Beat (acoustics) ,Electrical and Electronic Engineering ,Passive optical network ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Phase-shift keying ,Coding (social sciences) - Abstract
Novel phase-shift-keying (PSK)-Manchester coding scheme is suggested for the first time to be used in a 10-Gb/s wavelength-division-multiplexing passive optical network (PON) system. PSK-Manchester signal demonstrates much stronger tolerance to beat interference noise compared to that of differential phase-shift-keying and amplitude-shift-keying-Manchester signals. With this modulation format applied, the number of semiconductor optical amplifiers used as control gates in a PON system can be greatly reduced, which make the PON system more cost-effective.
- Published
- 2005
41. Reduction of polarization-dependent gain due to signal-to-signal Raman interaction in fiber Raman amplifier
- Author
-
Xiao Hann Lim, Chao Lu, Yixin Wang, Jian Chen, Zhihong Li, and Zhaohui Li
- Subjects
Optical amplifier ,Materials science ,business.industry ,Fiber raman amplifier ,Polarization (waves) ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Scrambler ,symbols.namesake ,Optics ,Raman amplifiers ,Wavelength-division multiplexing ,symbols ,Electrical and Electronic Engineering ,Polarization dependent ,business ,Raman spectroscopy - Abstract
An excellent polarization-dependent gain (PDG) suppression technique using a polarization scrambler is proposed in this letter. Investigations on PDG due to signal-to-signal Raman interaction among 40 wavelength-division-multiplexer signal channels were carried out experimentally to evaluate the system performance after incorporating a polarization scrambler in the system. It was confirmed by experiment that the use of polarization scrambler is an effective way to reduce PDG caused by signal-to-signal Raman interaction.
- Published
- 2005
42. Design of wavelength-switching erbium-doped fiber lasers with a multimode fiber Bragg grating using spatial-mode excitation and selection techniques
- Author
-
Jianzhong Hao, Lei Su, Zhihong Li, Chao Lu, and Yixin Wang
- Subjects
PHOSFOS ,Mode volume ,Materials science ,business.industry ,Physics::Optics ,Polarization-maintaining optical fiber ,Long-period fiber grating ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optics ,Fiber Bragg grating ,Fiber laser ,Optoelectronics ,Dispersion-shifted fiber ,Electrical and Electronic Engineering ,business ,Photonic-crystal fiber - Abstract
A multimode fiber Bragg grating (MMFBG)-based wavelength-switching erbium-doped fiber laser and its application in displacement sensing is proposed and demonstrated. According to the spatial-mode distribution in the multimode fiber (MMF), the modes reflected by the MMFBG at different wavelengths build a wavelength-dependent mode field on the transverse plane of the MMF. By varying spatial-launching position of the single-mode fiber against the MMFBG to achieve different mode group excitation and selection, single-wavelength lasing at 31 discrete wavelengths has been realized over a wide wavelength range.
- Published
- 2005
43. WDM Transmission of 16<tex>$,times,$</tex>10.709 Gb/s Over 640-km SSMF Using Cascaded Semiconductor Optical Amplifiers and DPSK Modulation Format
- Author
-
Zhihong Li, Yi Dong, Chao Lu, Zhaohui Li, Yixin Wang, and Jinyu Mo
- Subjects
Optical amplifier ,Computer science ,business.industry ,Optical modulation amplitude ,Optical performance monitoring ,Optical switch ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Transmission (telecommunications) ,Modulation ,Wavelength-division multiplexing ,Electronic engineering ,Electrical and Electronic Engineering ,Photonics ,business - Abstract
To extend transmission distance using cascaded in-line semiconductor optical amplifiers (SOAs) and differential phase-shift-keying modulation format, optimal operation conditions for SOAs, such as input power and operation current, are studied. 16/spl times/10.709-Gb/s wavelength-division-multiplexing transmission over 640-km SSMF with the optimal system design parameters is demonstrated. This is, to the best of our knowledge, the largest bit-rate distance product reported.
- Published
- 2004
44. 1050-km WDM Transmission of 8<tex>$,times,$</tex>10.709Gb/s DPSK Signal Using Cascaded In-Line Semiconductor Optical Amplifier
- Author
-
Jinyu Mo, Yi Dong, Zhihong Li, Chao Lu, and Yixin Wang
- Subjects
Optical amplifier ,Physics ,business.industry ,Optical cross-connect ,Optical performance monitoring ,Power margin ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optics ,Transmission (telecommunications) ,Modulation ,Wavelength-division multiplexing ,Electrical and Electronic Engineering ,business ,Amplitude and phase-shift keying - Abstract
We have performed eight-channel wavelength-division-multiplexing transmission over 1050-km single-mode fiber using cascaded in-line semiconductor optical amplifier and differential phase-shift keying modulation format for the first time; more than 6 dB of power margin was achieved over forward-error correction threshold. Factors that affect the transmission performance were discussed. It was found that four-wave mixing is the main factor that limits the maximum transmission distance. Larger capacity distance product can be realized by further optimizing the configuration of transmission link.
- Published
- 2004
45. Cascaded All-Optical Wavelength Conversion for RZ-DPSK Signal Based on Four-Wave Mixing in Semiconductor Optical Amplifier
- Author
-
Jinyu Mo, Chao Lu, Yixin Wang, Zhihong Li, and Yi Dong
- Subjects
Optical amplifier ,Materials science ,business.industry ,Keying ,Signal ,Atomic and Molecular Physics, and Optics ,Amplitude-shift keying ,Electronic, Optical and Magnetic Materials ,Four-wave mixing ,Optics ,Transmission (telecommunications) ,Modulation ,Electrical and Electronic Engineering ,business ,Phase-shift keying - Abstract
We have demonstrated ten-stage cascaded wavelength conversion together with 800-km transmission for 10-Gb/s return-to-zero differential phase-shift keying (RZ-DPSK) format using four-wave mixing (FWM) in semiconductor optical amplifiers. To the best of our knowledge, this is the first experiment reported on cascade wavelength conversion for RZ-DPSK format, which cannot be realized by methods based on cross-gain modulation and cross-phase modulation using a semiconductor optical amplifier. Compared with wavelength conversion using FWM for conventional on-off keying format, the signal-to-pump ratio for RZ-DPSK format can be increased to higher level to achieve better performance.
- Published
- 2004
46. Asynchronous sampling for Q-factor estimation using sampling pulse with wide pulsewidth
- Author
-
Chao Lu, Yixin Wang, Fu Ming Yue, Yi Dong, Tee Hiang Cheng, and Zhihong Li
- Subjects
Computer simulation ,Control theory ,Computer science ,Q factor ,Sampling (statistics) ,Electrical and Electronic Engineering ,Optical performance monitoring ,Signal ,Sample (graphics) ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Pulse (physics) ,Communication channel - Abstract
A novel method based on asynchronous sampling using sampling pulse with wide pulsewidth has been suggested for Q-factor estimation from amplitude histogram. The effectiveness of this method has been demonstrated through numerical simulation. It was found that, there exist a linear relationship between original Q value and the estimated Q factor using sample pulse with certain pulsewidth for both nonreturn-to-zero and return-to-zero signal format. This method is simple and easy to implement. It can be applied to either single channel or multi channel monitoring scheme.
- Published
- 2003
47. Continuously tunable microwave-photonic filter design using high-birefringence linear chirped grating
- Author
-
Lei Ding, Chao Lu, Yixin Wang, Xiaoke Yi, Xiufeng Yang, Fang Wei, and Wen-De Zhong
- Subjects
Materials science ,business.industry ,Physics::Optics ,Filter (signal processing) ,Grating ,Band-stop filter ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Filter design ,Optics ,Fiber Bragg grating ,Differential group delay ,Chirp ,Optoelectronics ,Electrical and Electronic Engineering ,Optical filter ,business - Abstract
We propose and demonstrate experimentally a novel microwave-photonic filter using a variable polarization delay line based on a high-birefringence linear chirped fiber Bragg grating. The filter is free from the problems associated with the optical coherence interference of the laser. It provides a continuous tuning capability without the need to change the wavelength of the input optical carrier, and offers high resolution filtering for real-time signal processing in radio frequency systems.
- Published
- 2003
48. Evaluation of intraband crosstalk in an FBG-OC-based optical cross connect
- Author
-
Zabih Ghassemlooy, Xiangnong Wu, Chao Lu, and Yixin Wang
- Subjects
Physics ,Multi-mode optical fiber ,business.industry ,Quantitative Biology::Molecular Networks ,Optical cross-connect ,Computer Science::Software Engineering ,Physics::Optics ,Optical performance monitoring ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Fiber-optic communication ,Optics ,Fiber Bragg grating ,Fiber optic splitter ,Optoelectronics ,Optical circulator ,Electrical and Electronic Engineering ,business ,Optical add-drop multiplexer - Abstract
An analytical model of intraband optical crosstalk in an N/spl times/N fiber Bragg grating optical circulator-based optical cross connect (OXC) is presented. Results show that the worst-case coherent crosstalk is /spl sim/22-26 dB higher than incoherent crosstalk, depending on the switching state of 2/spl times/2 OXC. In addition, a novel scheme of OXC with improved intraband crosstalk performance is proposed.
- Published
- 2002
49. Performance Comparison of Using SOA and HNLF as FWM Medium in a Wavelength Multicasting Scheme With Reduced Polarization Sensitivity
- Author
-
Zhaowen Xu, Yixin Wang, Jianguo Liu, Gaoxi Xiao, Tee Hiang Cheng, Yong-Kee Yeo, and Dawei Wang
- Subjects
Optical amplifier ,Optical fiber ,Multicast ,law ,Cross-phase modulation ,On-off keying ,Bit error rate ,Electronic engineering ,Optical polarization ,Atomic and Molecular Physics, and Optics ,Amplitude-shift keying ,Mathematics ,law.invention - Abstract
In this paper, we propose and demonstrate the practical all-optical wavelength multicasting scheme based on the four-wave mixing (FWM) effect in both a highly nonlinear fiber (HNLF) and a semiconductor optical amplifier (SOA). Then we carry out comprehensive comparisons of the performance differences between using the HNLF and SOA for this proposed multicasting scheme. Seven multicast channels are experimentally demonstrated by using three co-polarized probes and a modulated signal. The merit of the proposed scheme is that the polarization sensitivity is significantly reduced from more than 20 dB to approximately 5 dB using the HNFL and 2.5 dB using the SOA. The low polarization sensitivity leads to a difference of less than 1 dB in the power penalty of the multicast channels at bit error rate . In addition, we compare the multicasting performance of the OOK and differential phase-shift keying (DPSK) signals using the proposed scheme and found that the power penalties of the DPSK multicast channels in the HNLF and the SOA are less than 1.25 and 1.1 dB respectively, and the power penalties of the OOK multicast channels are less than 1.5 dB and 3.1 dB in the HNLF and the SOA, respectively.
- Published
- 2010
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