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IEEE Photonics Journal
Journal Prestige (SJR): 0.893  Citation Impact (citeScore): 3 Number of Followers: 18  Open Access journalISSN (Print) 1943-0655 Published by IEEE  [228 journals]
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- Thermal Performance of 940 nm AlGaAs-Based VCSELs Grown on Germanium
Authors: Jack Baker;Craig P. Allford;Sara Gillgrass;J. Iwan Davies;Samuel Shutts;Peter M. Smowton;
Pages: 1 - 4
Abstract: VCSEL thermal resistances are determined from power-current-voltage-wavelength measurements performed on nominally identical epitaxial structures grown on Ge and GaAs substrates. We show that the effective thermal conductivity of the VCSEL is increased when grown on Ge substrates.
PubDate: WED, 19 MAR 2025 09:17:17 -04
Issue No: Vol. 17, No. 2 (2025)
- New Paradigm for Beehive Monitoring System Using Infrared and Power Line
Communication
Authors: Da-Huei Lee;Wei-Wen Hu;Yuan-Long Lee;Tai-Yu Chen;
Pages: 1 - 9
Abstract: In recent years, smart beehive monitoring has attracted attention due to its highly profitable industry. However, colony collapse disorder (CCD) syndrome, which is described by the sudden disappearance of the bee colony, severely affects the honey bee industry in most countries of the world. The causes of CCD are not verified, but electromagnetic interference (EMI) is the possible one that appears in most beehive monitoring systems. Based on this motivation, this paper presents a new paradigm for beehive monitoring utilizing the proposed system consisting of a host module, multiple sensor modules, and relay modules. Each sensor module is responsible for collecting the in-hive parameters of each beehive such as temperature, humidity, hive weight, carbon dioxide, oxygen, and entrance counts. The collected sensor data are then transmitted to the relay module by infrared (IR) communication to avoid EMI. The relay module integrates the IR receiver and power line communication (PLC) transmitter technologies, where the former is used to receive optical signals with in-hive parameters, and the latter is used to transform the abovementioned signals into PLC interface. Moreover, a host module is introduced to aim at receiving the signals from multiple relay modules by the PLC interface. The distances of IR communication and PLC are determined through simulation results under the target bit error rate of $10^{-3}$ to provide accurate in-hive parameters with negligible interference from multiple beehives. Experimental results also show that the proposed system could meet the requirements of real-time and long-term data collection and transmission.
PubDate: TUE, 18 MAR 2025 09:19:32 -04
Issue No: Vol. 17, No. 2 (2025)
- Temperature-Insensitive Second-Order Microring Resonator for Dense
Wavelength Division Multiplexing (DWDM)
Authors: Fuling Wang;Xiao Xu;Chonglei Sun;Liuge Du;Jia Zhao;
Pages: 1 - 7
Abstract: To achieve temperature-insensitive passband responses of microring resonator (MRR) for DWDM signal processing, we design and fabricate a wavelength division multiplexer with four channels based on 2nd-order slot MRR with PMMA cladding layer. Four filters with different radii are connected in series to realize 1.5-nm channel space. In the process of design and optimization, the dense wavelength demultiplexer (DEMUX) exhibits admirable responses with broad 1-dB bandwidth (>0.64 nm, accounting for 43% of the channel spacing), steep band edge (shape factors ∼0.47) and high temperature stability (temperature-dependent wavelength shift (TDWS) < 0.25 pm/°C, which is 0.4% of ordinary MRR). Then the device is fabricated and measured. The box-type responses are obtained for all 4 wavelength channels. The measured 1-dB bandwidth is 1.1 nm and the shape factor is larger than 0.35. Due to the fabrication imperfections and process errors, the central wavelengths shifted from ideal values. The measured TDWS is less than 24.8 pm/°C, which is deteriorated from the design due to the incomplete filling of the PMMA cladding in the slot. Even so, the decrease of the TDWS, combined with the box-type response of 1-dB bandwidth of 1.1 nm in our design, makes the DEMUX tolerate the temperature variation of larger than ±22 °C without the help of electrical temperature control. The results indicate the great potential of the designed device for DWDM applications.
PubDate: MON, 17 MAR 2025 09:19:31 -04
Issue No: Vol. 17, No. 2 (2025)
- Digital Interferometric Open Loop Phase Recovery in a Fiber Optic
Gyroscope
Authors: Paul G. Sibley;Justin Wong;Malcolm B. Gray;Jong H. Chow;Chathura P. Bandutunga;
Pages: 1 - 6
Abstract: We present the first use of a Digitally Enhanced Homodyne readout on a Sagnac interferometer, demonstrating the technique's capability as a readout method for high dynamic range, open loop interferometric fiber optic gyroscopes. We achieve an optical phase noise floor of 0.7 $\mu$rad/$\sqrt{\text{Hz}}$, and phase linearity of 8 ppm demonstrated over a phase dynamic range of $16\pi$. We rotation calibrate the system using a rate table, confirming an angular random walk (ARW) of 0.0014 deg/$\sqrt{\text{hr}}$, bias instability of 0.012 deg/hr.
PubDate: THU, 13 MAR 2025 09:16:52 -04
Issue No: Vol. 17, No. 2 (2025)
- Reservoir Computing for Few-Mode Fiber Channel OSNR Monitoring in Deep
Learning Frameworks
Authors: Jianjun Li;Tianfeng Zhao;Baojian Wu;Kun Qiu;Feng Wen;
Pages: 1 - 7
Abstract: This paper presents a novel optical performance monitoring (OPM) scheme based on reservoir computing (RC) and Resnet network for monitoring the optical signal-to-noise ratio (OSNR) of few-mode transmission channels, without the need for any demodulation process. By using 300 RC nodes, the number of floating-point operations (FLOPs) is reduced by 75%, with almost no change in prediction accuracy compared to a network without RC. In a system ranging from 0 to 30 dB, 40 simulation runs yield an OSNR prediction accuracy band around 0.9900. We also investigate the prediction accuracy when using different spectral information, with results showing that frequency-domain information effectively captures the characteristics of both signal and noise. Additionally, we examine the impact of different mode combinations on OSNR prediction accuracy and find that the prediction performance is nearly unaffected by the mode combination.
PubDate: WED, 12 MAR 2025 09:16:51 -04
Issue No: Vol. 17, No. 2 (2025)
- Polarization-Insensitive Nano-Metamaterial Sensor With Near-Infrared μ
and ϵ Negative Properties for Early Cancer Detection via Exosome Analysis
(70 THz to 3 PHz)
Authors: Musa N. Hamza;Mohammad Tariqul Islam;Sunil Lavadiya;Iftikhar ud Din;Bruno Sanches;Slawomir Koziel;Syeda Iffat Naqvi;Abinash Panda;Mohammad Alibakhshikenari;B. Virdee;Md. Shabiul Islam;
Pages: 1 - 15
Abstract: Metamaterials (MTMs) have emerged as essential components in high-performance electromagnetic devices, including sensors and absorbers. This study presents a polarization-insensitive nano-metamaterial sensor with exceptional angular stability and a wide operating range of 70 THz to 3 PHz. The sensor achieves an average absorption rate of 97% across this range, making it highly suitable for applications in biomedical engineering. By integrating microwave imaging (MWI) techniques, the sensor can detect circulating cancer exosomes (CCEs) with high sensitivity, effectively distinguishing them from normal exosomes. Exhibiting double-negative MTM properties (negative permittivity and permeability) in the near-infrared (NIR) range (70 THz to 400 THz), the sensor enhances sensitivity for early cancer detection. A detailed analysis of its properties, including impedance (Z), phase, and S11 parameters (real and imaginary components), demonstrates its superior performance. This non-invasive, label-free approach to detecting cancer biomarkers represents a significant step forward in advancing personalized healthcare.
PubDate: TUE, 11 MAR 2025 09:17:26 -04
Issue No: Vol. 17, No. 2 (2025)
- Multi-Aperture Adaptive Fiber-Coupled Free-Space Optical Communication
System: Scintillation Mitigation and Turbulence Compensation Experiment
Based on Gamma-Gamma Channel Modeling
Authors: Ziting Pan;Yuting Li;Yijie Shen;Ziqiang Li;Guan Huang;Chao Geng;Xinyang Li;
Pages: 1 - 7
Abstract: Free-space optical communication is an effective alternative solution to address the “last mile” bottleneck in fiber-optic communication systems. However, its practical performance is significantly affected by phase perturbations and intensity scintillation induced by atmospheric turbulence effects. This paper proposes a multi-aperture adaptive fiber-coupled communication architecture, systematically investigating the optical transmission characteristics in turbulent channels through a combined approach of theoretical modeling and experimental validation. Utilizing the Gamma-Gamma turbulence channel model, quantitative analyses are conducted to elucidate the relationships between the scintillation index, the number of transmitting apertures, and the bit error rate. By establishing an outdoor 2.1 km experimental platform, we demonstrate that multi-aperture diversity transmission combined with closed-loop control reduces the scintillation index by 60% while achieving 10 Gbit/s error-free communication under weak turbulence conditions. Experimental results indicate that the proposed architecture enhances coupling power while maintaining high communication quality. Its modular design ensures high compatibility with mature fiber-optic communication components, providing a solution for constructing low-complexity, high-reliability hybrid optical communication systems in urban environments.
PubDate: TUE, 11 MAR 2025 09:17:26 -04
Issue No: Vol. 17, No. 2 (2025)
- Predicting the Evolution of the Supercontinuum Generation With CNN-LSTM
Model
Authors: Yi Feng;Ruiyuan Liu;Xinyue Chang;Xiangzhen Huang;Yuan He;Ning Li;Tiantian Zhou;Chujun Zhao;
Pages: 1 - 5
Abstract: We propose a hybrid deep learning model, namely convolutional neural network–long short-term memory (CNN-LSTM) approach to investigate the evolution of the supercontinuum (SC) generation numerically. The hybrid model can use the CNN model to extract and map the local features of the sequence, followed by the LSTM to predict the overall trend of the SC generation. With the trained model by learning the propagation dynamics of the generalized nonlinear Schrödinger equation, the consistent outcome for the neural network predictions and numerical solutions has been obtained. The combined neural network can effectively solve the complex nonlinear propagation problems and maintain high accuracy compared with the LSTM, GRU neural networks for different incident power. The hybrid approach can facilitate the design and optimization of the spectral or temporal intensity distribution of SC generation, and may offer guidance for designing SC source for specific applications.
PubDate: MON, 10 MAR 2025 09:17:04 -04
Issue No: Vol. 17, No. 2 (2025)
- Quadratic Vortex Optical Pin Beam With OAM Mode Anti-Degradation
Characteristic
Authors: Huahua Wang;Meiling Guan;Hongyue Xiao;Hongwei Jiang;Changqi Zhang;Yang Liu;Fei Chen;Lu Gao;Ze Zhang;
Pages: 1 - 8
Abstract: Orbital angular momentum (OAM) signal mode crosstalk and energy loss induced by atmospheric turbulence are challenging phenomena commonly occurring in high-capacity and high-speed OAM-based free-space optical communications. In this paper, we combine the optical pin beam (OPB) that resists atmospheric turbulence with the quadratic vortex phase (QVP) to realize a communication transmission beam based on weakening the degradation of the OAM signal mode. The probability densities of a single OAM mode of an optical pin vortex beam carrying a QVP (QVP-OPVB), after passing through an anisotropic non-Kolmogorov turbulent atmosphere, are theoretically derived. Through numerical simulation, it is found that QVP can be regarded as a superposition of multiple OAM modes, and the energy transfer between OAM modes during the propagation can compensate for the degradation of the OAM spectrum caused by atmospheric turbulence. Compared to the OAM spectra of the Gaussian vortex beam carrying QVP (QVP-GVB), the QVP-OPVB has better anti-crosstalk performance in a turbulent environment with a long propagation distance and a small receiving aperture. This beam has applications in free-space optical communication to enhance the interference resistance of the communication link.
PubDate: FRI, 07 MAR 2025 10:42:36 -04
Issue No: Vol. 17, No. 2 (2025)
- High Power Tandem Pumped Ytterbium-Doped Fiber Amplifier Employing Low-NA
Fiber
Authors: Mengfan Cui;Chongwei Wang;Haobo Li;Zhiyong Pan;Hu Xiao;Zilun Chen;Zhiping Yan;Pengfei Ma;Zefeng Wang;Jinbao Chen;
Pages: 1 - 7
Abstract: The power scaling of tandem pumped ytterbium-doped fiber lasers (YDFLs) is mainly limited by the nonlinear effect such as the stimulated Raman scattering (SRS). Applying a kind of YDF featuring a large mode field area (LMA) and few guided modes is one of the effective methods to improve the SRS threshold while achieving mode control. With the benefits of small V values, few guided modes and LMA, low-numerical aperture (NA) fibers have potential for effective mode control and high SRS threshold. In this contribution, a low-NA YDF with a core/ inner cladding diameter of 40/250 μm and core NA∼0.051 is fabricated for high power tandem pumped fiber laser. Compared with the conventional YDF, the low-NA fiber amplifier reaches a maximum output power of 7.1 kW with beam quality M2∼2.3 using a forward tandem pumping scheme, providing significant advantages of improving beam quality and transverse mode instability (TMI) threshold. This work indicates the great potential of low-NA fibers applied in tandem-pumped fiber lasers for high-power laser systems requiring further power scaling and excellent beam quality, such as precision industrial machining.
PubDate: WED, 05 MAR 2025 09:17:57 -04
Issue No: Vol. 17, No. 2 (2025)
- Umbrella-Like Dual-Axis Mirror Scanner Fabricated With FDM 3D Printing and
Its Application in Realizing a Dynamic FOV Camera
Authors: Ming-Te Chiang;Yi-Wen Cheng;Wei-An Tsui;Pin-Hung Yeh;Ching-Kai Shen;Jui-che Tsai;
Pages: 1 - 6
Abstract: In this paper, we demonstrate a low-cost mirror scanner design of umbrella-like architecture. The primary structures are 3D-printed using PLA (polylactic acid) as the material. A 400 mm2 aluminum–deposited silicon chip is fixed on the mirror frame, which is part of the 3D-printed assembly, and serves as the reflective mirror. Miniature permanent magnets are embedded in the mirror frame so that the mirror can then be electromagnetically driven. Our latest-version scanner reaches optical scan angles of 7.8 and 7.4 degrees for the x- and y-scans at their resonant frequencies (37 Hz and 49 Hz), respectively. Under DC actuation, a full optical scan range of 10.1 degrees in the x- direction can be achieved when the voltage is tuned from +12 V (+0.089 A) to −12 V (−0.089 A). Additionally, we will demonstrate its integration with a smart phone camera to achieve a dynamic FOV (field of view).
PubDate: WED, 05 MAR 2025 09:17:57 -04
Issue No: Vol. 17, No. 2 (2025)
- Photonics Breakthroughs 2024: Nonlinear Photonic Computing at Scale
Authors: Hao Wang;Jianqi Hu;Andrea Morandi;Alfonso Nardi;Fei Xia;Xuanchen Li;Romolo Savo;Qiang Liu;Rachel Grange;Sylvain Gigan;
Pages: 1 - 4
Abstract: A photonic neural network utilizes photons instead of electrons to process information, with the prospect of higher computing efficiency, lower power consumption, and reduced latency. This paper reviews several recent breakthroughs in large-scale photonic neural networks incorporating nonlinear operations. Specifically, we highlight our recent work, which leverages multiple light scattering and second harmonic generation in a slab of disordered lithium niobate nanocrystals for high-performance nonlinear photonic computing. The interplay of these optical effects not only enhances the computational capabilities of photonic neural networks but also increases the number of photonic computing operations. In addition, we discuss current challenges and outline future directions of nonlinear photonic computing. These advancements pave the way for exploring new frontiers in optical computing, unlocking opportunities for innovative experimental implementations, broad applications, and theoretical foundations of photonic neural networks.
PubDate: TUE, 04 MAR 2025 09:17:35 -04
Issue No: Vol. 17, No. 2 (2025)
- Estimation of an Abnormal Noise Location Over Multi-Span Optical Fiber
Link Based on Nonlinear Fourier Transform
Authors: Takumi Motomura;Akihiro Maruta;Hideaki Shimpo;Ken Mishina;
Pages: 1 - 14
Abstract: In the next-generation optical fiber networks, in addition to ultra-high speed and high capacity, early recovery from disasters and failures is required to realize highly reliable networks. Recently, various methods for estimating abnormal locations using coherent receivers and digital signal processing have been proposed. This research proposes the application of nonlinear Fourier transform (NFT) for detecting abnormality. Particularly, we explore a method for estimating the abnormal noise location by monitoring the variances and covariance of the discrete eigenvalues in the NFT. The feasibility and characteristics of the proposed method are investigated through numerical simulations. For the details of the proposed method, we investigate the dependency of the eigenvalue configuration of signals, which is used for abnormality detection. Moreover, we confirm that the proposed method remains effective with variations in the noise level and the location of the abnormal noise. Ultimately, the proposed method achieves a kilometer-order estimation accuracy by employing appropriate parameters. In addition, we demonstrate that the proposed method is applicable to the case where the launch optical power is shifted from the optimum or an optical fiber link with a different span length.
PubDate: WED, 26 FEB 2025 09:18:33 -04
Issue No: Vol. 17, No. 2 (2025)
- Generation of Random Microwave Pulse Based on Random Optoelectronic
Oscillator
Authors: Junfeng Ren;Ping Li;Chenyang Ma;Zhengyang Xie;Xin Zhao;Zheng Zheng;
Pages: 1 - 8
Abstract: Optoelectronic oscillator (OEO) is a high-quality microwave source that can generate various forms of microwave signals, and structures for generating complex signals using OEO are constantly being proposed. We propose an OEO-based microwave pulse generation system where each sub-pulse is composed of random signal. The random fiber bragg gratings(R-FBG) were introduced to generate the random signal by using the OEO vibration characteristics. The output characteristics of the OEO loop are then modified by modulation of the bias voltage, thereby changing the output characteristics of the OEO loop. Finally, the present OEO system generates random microwave pulse signals with adjustable pulse envelopes, adjustable duty cycles and adjustable repetition rates.
PubDate: THU, 20 FEB 2025 09:22:46 -04
Issue No: Vol. 17, No. 2 (2025)
- Wavefront Reconstruction for a Holographic Modal Wavefront Sensor Based on
Extreme Learning Machine
Authors: Han Cao;Kainan Yao;Jianli Wang;Minglu Li;Leqiang Yang;Zhiqiang Xu;
Pages: 1 - 9
Abstract: The intermodal crosstalk effect as well as the limited dynamic range of holographic modal wavefront sensors (HMWFSs) significantly affect their wavefront-sensing accuracy. Thus, this study was aimed at proposing an extreme learning machine (ELM)-based wavefront-reconstruction algorithm for holographic HMWFSs to overcome the errors caused by crosstalk as well as extend the dynamic range of the sensors. The simulation results indicated that the proposed ELM-based algorithm reduced the crosstalk-induced residual wavefront root mean square error to 4.7% of the initial value, and this was 84.6% lower than the reduction achieved by the conventional sensitivity-matrix method. After selecting the optimal range of training samples, the ELM model further reduced the residual error by approximately 74% under aberration conditions, where the conventional method reached its convergence limit. Thus, we proposed an ELM model for mitigating the issue of the linear regression relationship between the differential signals measured by HMWFS and the incident-wavefront Zernike-mode coefficients under the aberration-mode crosstalk effect.
PubDate: MON, 17 FEB 2025 09:16:50 -04
Issue No: Vol. 17, No. 2 (2025)
- Influence of the Passivation Method on the Performance of 635 nm Ridge
Waveguide Lasers
Authors: Jos E. Boschker;David Feise;Uwe Spengler;Peter Ressel;Katrin Paschke;Andrea Knigge;
Pages: 1 - 4
Abstract: High power, compact, red edge-emitting lasers based on GaInP quantum wells are desirable for applications such as laser display technologies or two-photon upconversion. Here, we investigate the influence of passivation methods on the performance of 635 nm ridge waveguide lasers. We demonstrate that vacuum cleaving results in a higher facet stability compared to hydrogen cleaning, resulting in a reliable output power for 7.5 μm wide emitters of 200 mW for one week and 160 mW for 2000 hours. Moreover, our investigation shows that it is essential to consider the thermal budget of passivation methods for the optimization of the laser performance of phosphide-based lasers.
PubDate: FRI, 14 FEB 2025 09:17:34 -04
Issue No: Vol. 17, No. 2 (2025)
- All-Fiber Broadband Photon Pair Generation in Dispersion Flattened Highly
Non-Linear Fibers
Authors: Anadi Agnihotri;Pradeep Kumar Krishnamurthy;
Pages: 1 - 7
Abstract: We demonstrate an all-fiber broadband photon pair source based on four wave mixing (FWM) process in dispersion flattened highly non-linear fiber (DF-HNLF). The fiber exhibits a zero dispersion slope near 1550 nm, allowing phase-matched FWM over entire S, C, and L bands and thus efficient generation of signal and idler photons. A comparative theoretical study between conventional dispersion-shifted fiber (DSF) and DF-HNLF highlights the spectral range differences in the generation of photon pairs. We measure coincidence counts at three different sets of wavelengths. To study the effects of Raman scattering, which acts as noise source in these types of fibers, we calculate the correlation $g^{(2)}(\tau)$ at different pump powers. We use stimulated emission tomography to characterize the generation of photon pairs across the S, C, and L bands. We show that DF-HNLF is an ideal medium for generating correlated photons over a broad spectral range ($>\!\!100\,\text{nm}$), making it suitable for frequency-multiplexed quantum communication systems. We estimate the photon pair generation efficiency to be 0.05 $\text{mW}^{-2}/\text{pulse}$.
PubDate: FRI, 14 FEB 2025 09:17:34 -04
Issue No: Vol. 17, No. 2 (2025)
- 70 MW-Level Picosecond Mid-Infrared Radiation Generation by Difference
Frequency Generation in AgGaS2, BaGa4Se7, LiGaSe2, and LiGaS2
Authors: Michal Jelínek;Milan Frank;Václav Kubeček;Ondřej Novák;Jaroslav Huynh;Martin Cimrman;Michal Chyla;Martin Smrž;Tomáš Mocek;
Pages: 1 - 7
Abstract: Comparative study of nonlinear crystals for picosecond difference frequency generation in mid-IR is presented. Nonlinear crystals of AgGaS2, BaGa4 Se7, LiGaSe2, and LiGaS2 were studied. In order to investigate the dependence of efficiency on the crystal length, three sets of crystals with lengths of 2, 4, or 8 mm were tested. The developed tunable DFG system was driven by the 1.03 µm, 1.8 ps, Yb:YAG thin-disk laser system operated at the repetition rate of 10 or 100 Hz. As the best result, picosecond mid-IR pulses at a wavelength of $\sim$7 µm with the energy up to 130 µJ corresponding to the peak power of $\sim$72 MW were generated using the 8 mm long LiGaS2 crystal. Using the BaGa4 Se7 crystal, DFG tunability in the wavelength range from 6 up to 13 µm was achieved.
PubDate: FRI, 14 FEB 2025 09:17:34 -04
Issue No: Vol. 17, No. 2 (2025)
- Modular Arithmetic of Microwave Frequency Combs Generated by a Modulated
Photonic Oscillator
Authors: Georgia Himona;Yannis Kominis;
Pages: 1 - 9
Abstract: This study explores the dynamics of optically injected semiconductor lasers under current modulation by periodic pulse sequences of various characteristics, focusing on the generation and control of microwave frequency combs (MFCs). Using simplified one-dimensional models –Poincaré circle maps–, the system's response to Dirac-delta, rectangular, and Gaussian pulse trains is analyzed. Modulation parameters such as amplitude, pulse width, and frequency detuning govern the emergence of frequency-locked states and chaotic oscillations, leading to distinct spectral outputs. A modular arithmetic relation between the frequencies of the modulation and the internal oscillation is shown to result in integer and fractional frequency division. The findings offer insights into tuning MFCs for applications in high-resolution measurement, microwave photonics, and data transmission.
PubDate: THU, 13 FEB 2025 09:18:46 -04
Issue No: Vol. 17, No. 2 (2025)
- Room Temperature InGaAs/AlGaAsSb Single Photon Avalanche Diode
Authors: J. Taylor-Mew;L. Li;T. Blain;C. H. Tan;J. S. Ng;
Pages: 1 - 6
Abstract: Near-infrared Single Photon Avalanche Diodes (SPADs) are the dominant, practical single photon detectors for quantum applications and low-level optical sensing. Although some infrared SPADs can operate at room temperature, thermoelectric coolers are still essential, increasing complexity (operation and device packaging) and power consumption. Passively-cooled SPADs could be realized by avalanche materials exhibiting better temperature stability. A promising candidate is the InGaAs/AlGaAsSb SPAD, because the AlGaAsSb multiplier is highly stable with temperature. In this work, we report single photon detection performance of InGaAs/AlGaAsSb SPADs at room temperature and 1550 nm wavelength using multiple devices for each type of measurements. With 0.1 photons per pulse and 15 μm diameter devices, the maximum SPDE was 14% at DCR of 30 Mc.s−1, respectively. The best NEP value is around an order of magnitude higher than InGaAs/InP SPADs, but are comparable to InGaAs/InAlAs SPADs. Within the relevant overbias range and repetition rate up to 1 MHz, the DCR was unaffected by afterpulsing. Timing jitters were as low as 150 ps, matching InGaAs/InP SPADs. The results of this work are much more competitive than the previous report of InGaAs/AlGaAsSb SPAD, which required cooling to 200 K to detect single photons. Further research could help InGaAs/AlGaAsSb SPADs progressing towards passively-cooled single photon detectors for room temperature operation.
PubDate: THU, 13 FEB 2025 09:18:45 -04
Issue No: Vol. 17, No. 2 (2025)
- Hybrid Indoor Positioning System Based on LED Array
Authors: Lu Chen;Lifang Feng;Jianping Wang;Tianyi Zhang;Haijun Zhang;Zhuo Xue;
Pages: 1 - 11
Abstract: Visible light positioning (VLP) is one of the effective solutions for low-cost and high-precision indoor positioning in the emerging wireless communication ecosystem, particularly in the context of 6G networks, due to its advantages of low latency, high data transmission rates, and immunity from radio frequency induced electromagnetic interference. However, severe performance limitations, including line-of-sight dependency, signal attenuation caused by obstacles, and restricted coverage, present a major challenge for the development of VLP. This article constructs an LED array-based hybrid indoor positioning system. An innovative LED array beacon is developed to simultaneously transmit coordinate and graphical information. A hybrid receiving structure, comprising an image sensor (IS) and a photodetector (PD), is constructed along with a dedicated hybrid positioning algorithm. This algorithm leverages image processing techniques to track the target trajectory, converts light intensity to identify the identification of LED, which finally resolves the target's precise world coordinates. The system's performance was validated through three experimental trials. The results demonstrate that the proposed beacon effectively covers the entire positioning area, achieving an average positioning error of 8.32 cm and a maximum positioning distance of 6.8 m. These results suggest that the proposed system provides a robust and efficient solution for precise indoor positioning applications in next-generation wireless communication networks.
PubDate: THU, 13 FEB 2025 09:18:45 -04
Issue No: Vol. 17, No. 2 (2025)
- Decomposing-Recomposing Network: A Novel Reconstruction and Enhancement
Approach for Low-Light Image
Authors: Zhenyang Ding;Nan Wang;
Pages: 1 - 9
Abstract: Low-light imaging has long been a fundamental yet challenging area in optical imaging, primarily due to photon-starved conditions that not only impair image visibility but also amplify sensor noise. Traditional enhancement techniques mainly focus on illumination adjustments and often fall short in addressing the inherent trade-off between boosting brightness and suppressing noise. Moreover, many existing methods assume expert-level noise management during image capture, thereby overlooking the crucial frequency-dependent characteristics of noise distribution. Our observations reveal that while simultaneously enhancing brightness and reducing noise is challenging, noise intensity indeed varies across different frequency layers. In low-light images, the noise predominantly appears as Additive White Gaussian Noise (AWGN) concentrated in the high-frequency domain. Inspired by this phenomenon, we introduce a novel model based on the principles of decomposition and recomposition. Extensive experiments conducted on several baseline low-light datasets—including LOL-v1, LOL-v2, MEF, LIME, DICM, and NPE—demonstrate that our approach not only outperforms the latest methods quantitatively and qualitatively but also excels in handling real and complex low-light scenarios. Furthermore, our method consistently produces superior visual outcomes compared to existing techniques.
PubDate: THU, 13 FEB 2025 09:18:45 -04
Issue No: Vol. 17, No. 2 (2025)
- Fast, Accurate, and Low-Disturbance Automatic Bias Control for Coherent
Optical Transmitter Using Dither Vector Mapping Monitoring
Authors: Hongyu Li;Xinghan Li;Mengfan Cheng;Qi Yang;Ming Tang;Deming Liu;Lei Deng;
Pages: 1 - 5
Abstract: A fast, accurate automatic bias control (ABC) scheme with low disturbance for optical IQ modulators is proposed by using the dither-vector-mapping monitoring (DVMM) technique. The proposed scheme solely necessitates vector length calculation via addition and subtraction operations and obviates the necessity of employing a direct digital synthesis (DDS) module, in contrast to conventional ABC schemes. By this means, the proposed scheme demonstrates reduced algorithmic complexity and a faster convergence rate, requiring only 0.3∼0.5 s to track and lock from a random bias point to a linear bias point, about 30 times faster than current commercial products. Moreover, unlike the commonly used single-tone dither signal (STDS), the PRBS-based dither signal in this scheme is broadband and has lower power spectral density and peak power at the same power level. Therefore, it not only induces lower nonlinear distortion in the transmitted signal but also has strong noise resistance, contributing to good control accuracy and robustness. The performance of DVMM-based ABC and STDS-based ABC is evaluated in 40/20 Gbaud 16/64 QAM coherent optical transmission systems, showing that DVMM can effectively reduce the bit error rate (BER) and has superior transmission performance.
PubDate: WED, 12 FEB 2025 09:16:32 -04
Issue No: Vol. 17, No. 2 (2025)
- Numerical Simulation of Thermal Lens Effect in Laser Diode End-Pumped
Solid-State “Quasi-Rotating” Lasers
Authors: Minghai Wang;Zhuanglin Qian;Xuan Lv;Ying Wang;Peifeng Chen;
Pages: 1 - 9
Abstract: To address thermal effects in end-pumped solid-state lasers, this paper introduces a new motion concept called “quasi-rotating” and proposes a specialized method for evaluating the thermal focal length of dynamic gain medium, which proves valuable for resonator design. Using the finite element numerical analysis method, we analyze the changes of the temperature field distribution within the crystal and demonstrate the effectiveness of the “quasi-rotating” cooling system in thermal management. The results show that the “quasi-rotating” frequency and pump power have a more significant influence on the thermal lens effect than the cooling water temperature. Compared to previous studies, our new method accurately predicts the thermal focal length of the moving crystal and provides direct guidance for resonator design, as shown in this paper. These findings provide a theoretical foundation for the design and enhancement of high-power solid-state lasers. Moreover, the approach offers meaningful insights for the design of other non-traditional lasers with dynamic gain medium.
PubDate: THU, 06 FEB 2025 09:18:26 -04
Issue No: Vol. 17, No. 2 (2025)
- Capacitively Coupled Silicon Modulator Fabricated on the Standard
Silicon-on-Insulator Platform
Authors: Ahmed Shariful Alam;Hao Sun;Joyce K. S. Poon;José Azaña;J. Stewart Aitchison;
Pages: 1 - 8
Abstract: Silicon-on-insulator (SOI) based silicon modulators are essential for modern optical communication links. Almost all these modulators are based on a rib waveguide structure. In this paper, we report our observation of a silicon modulator in a silicon strip waveguide. Such waveguide have a simpler structure, higher optical confinement, lower dispersion and can result in modulators with improved bandwidth compared to a rib waveguide. We demonstrated a novel strip waveguide-based Mach-Zehnder interferometer (MZI) silicon modulator fabricated in the Multi Project Wafer (MPW) run from a commercial foundry. Using a self-heterodyne measurement system we estimated a half-wave-voltage-length product (V $_{\pi }$ L) of $\sim$ 9.4 V.cm at 20 MHz modulation signal. The electro-optic (EO) measurement of the proposed modulator can generate the first order sidebands up to 68 GHz and almost a flat frequency response was observed.
PubDate: THU, 06 FEB 2025 09:18:26 -04
Issue No: Vol. 17, No. 2 (2025)
- Beam-Shape-Based Angle-of-Arrival Estimation in Free-Space Laser
Communication
Authors: Hannes F. Dreier;Ali Derakhshandeh;Andrej Harlakin;Peter A. Hoeher;
Pages: 1 - 16
Abstract: A novel technique is proposed for estimating the angle-of-arrival (AOA) in free-space laser communication based on the shape of a laser beam spot on a flat surface. Two methods are introduced: one where ellipses are fitted to the intensity contour of the beam spot, and another where a least-squares fit of an AOA-dependent two-dimensional Gaussian distribution is applied to the intensity distribution. The effects of beam displacement, discretization, and noise on estimation performance are analyzed. The Cramér-Rao lower bound is derived and examined in relation to the true AOA. Both methods are verified through numerical simulations and experiments. For experimental validation, a novel beam sampling technique using a liquid-crystal display and a single photodiode is developed.
PubDate: THU, 06 FEB 2025 09:18:26 -04
Issue No: Vol. 17, No. 2 (2025)
- Multiband Radar Using Microwave Photonic Time-Frequency Limiter for
Real-Time Detection in Interference Scenarios
Authors: Luhang Xing;Shangyuan Li;Xiaoxiao Xue;Xiaoping Zheng;Bingkun Zhou;
Pages: 1 - 8
Abstract: In this paper, a novel strategy of employing microwave photonic (MWP) time-frequency limiter (TFL) for microwave photonic multiband radar is proposed to suppress the interference, achieving real-time response to the interference scenarios and high-resolution target detection. By mapping the echo signal into optical domain, the time-frequency characteristic is re-constructed through stimulated Brillouin scattering (SBS), realizing the selective suppression on high-power optical signal mapped by the interference. Based on this concept, a MWP TFL system based on the optical spectrum processing is constructed, and proof-of-concept experiments are demonstrated to verify the feasibility of the proposed strategy under different interference scenarios. Employing the proposed MWP TFL, the signal-to-noise ratio of the detection results, which is severely degraded by asynchronous interference, can be improved by 27.97 dB, and the suppression ratio on the false targets generated by the synchronous interference can reach 34.10 dB. The experimental results shows that the strategy can further enhance the survivability of multiband radar without compromising the range resolution for target detection. In addition, experiments are carried out to demonstrate the capability of the proposed strategy under different interference-to-signal ratios, showing a good adaptability to the complex interference scenarios.
PubDate: TUE, 04 FEB 2025 09:18:14 -04
Issue No: Vol. 17, No. 2 (2025)
- Single-Polarization Coupler Based on Dual-Core Photonic Bandgap Fiber With
Thin Slab Waveguide
Authors: Yunhao Zhu;Chuanfei Yao;Xuan Wang;Guochuan Ren;Shu Liu;Jiaqian Si;Pingxue Li;
Pages: 1 - 6
Abstract: An ultralow insertion loss (IL) and ultrahigh polarization extinction ratio (PER) single-polarization (SP) coupler based on dual-core photonic bandgap fiber (DC-PBF) with thin slab waveguide (TSW) is proposed. By introducing the TSW structure into the DC-PBF, the loss of the secondary eigenstate of polarization (ESOP) mode is significantly increased through the strong mode coupling with the higher-order TE/TM mode of the TSW. Thus, the SP performance is achieved through the significantly high loss of the secondary ESOP mode in conjunction with the relatively low loss of the primary ESOP mode. In order to design ultralow IL and ultrahigh PER SP couplers based on DC-PBF with TSW, the low-loss SP DC-PBF with TSW is established by considering the impacts of structure parameters and wavelength on both loss and coupling performance. Furthermore, the dependences of powers, coupling ratio, and PER in x(y)-polarization in two cores with different lengths are analyzed for the SP coupler based on DC-PBF with TSW. Finally, three ultralow IL and ultrahigh PER 3 dB SP couplers based on DC-PBF with TSW are designed through theoretical calculation of fabrication tolerance and operation bandwidth. These couplers exhibit narrow-band high PER (∼ 27.2 dB), short-length ultralow IL (∼ 0.00054 dB), and long-length ultrahigh PER (∼ 61.88 dB), respectively. The proposed ultralow IL and ultrahigh PER SP couplers based on DC-PBF with TSW have potential applications in high-precision resonant PBF optic gyroscopes as well as other PBF applications.
PubDate: TUE, 04 FEB 2025 09:18:14 -04
Issue No: Vol. 17, No. 2 (2025)
- High Ambient Contrast Ratio and Efficiency LED Display Devices Utilizing
Inverted Packaging Structure
Authors: Zong-Tao Li;Yi-Hua Qiu;Jia-Sheng Li;Jin-Cheng Li;Bin-Hai Yu;Xin Zhu;Xin-Rui Ding;
Pages: 1 - 7
Abstract: Highly light-absorbed encapsulation is generally used to eliminate the ambient light for light-emitting diode (LED) display devices, it is challenging to simultaneously achieve a high ambient contrast ratio (ACR) and high light output efficiency (LOE). To solve this problem, we propose an inverted packaging structure for LED display devices. The LED chips’ emitting surface is mounted on the transparent carrier board (TCB) while the backside is packaged by the composite encapsulation, causing that the substrate is inverted to the topside of devices. As a result, the chips can emit light directly from the TCB and avoid the absorption loss of the encapsulation, leading to the high ACR and LOE performances. Compared to traditional devices, the inverted device showed an average increase of over 800% in luminous flux (LF) and LOE, and an average increase of over 390% in ACR. Additionally, the devices exhibited excellent soldering performance, corrosion resistance, airtightness, and thermal stability. This novel device overcomes the bottleneck of achieving both high ACR and high LOE, providing new insights for the development of LED display technology. Future work can further optimize the structure and materials of the TCB and composite encapsulation to enhance device performance.
PubDate: FRI, 31 JAN 2025 09:16:56 -04
Issue No: Vol. 17, No. 2 (2025)
- Flexible Broadband Frequency Hopping Signal Generation Based on a
Filter-Free Optoelectronic Conversion Loop
Authors: Xun Wang;Jingjing Hu;Yiying Gu;Xiaozhou Li;Shuai Zu;Dongxu Li;
Pages: 1 - 7
Abstract: We propose and experimentally demonstrate a photonics method for generating broadband frequency hopping (FH) microwave signals based on an optoelectronic conversion (OEC) loop. In the proposed scheme, FH signals are generated after feedback modulation when low-frequency seed pulses are applied to the MZM in the OEC loop. The scheme can achieve a large-scale frequency hopping between S/C/X bands and C/X/Ku frequency bands. The experimental results indicate that 3-level FH signals with frequencies of 3/6/12 and 4/8/16 GHz have been successfully generated. Frequency-hopped linear frequency modulation (FH-LFM) signals from 2.5 GHz to 4.5 GHz, 5 GHz to 9 GHz and 10 GHz to 18 GHz with different chirp rates can also be generated. The achievable time-bandwidth product (TBWP) is as high as 15400. The autocorrelation results indicate that FH-LFM has good pulse compression ability. The pulse width, period and bandwidth of the FH signal can be adjusted flexibly. The proposed system does not require any optical filters or high-frequency RF signal source. It has potential to apply in radar, electronic warfare and wireless communication systems.
PubDate: THU, 30 JAN 2025 09:17:52 -04
Issue No: Vol. 17, No. 2 (2025)
- Probability of Exposure of Optical Receiver to Direct Sunlight in
FSO-Based Wireless Mobile Communications
Authors: Gihong Park;Hoon Kim;
Pages: 1 - 11
Abstract: Free-space optics (FSO) communication systems can be applied to cellular mobile communication networks to offer high-data-rate services to mobile users. In such networks, the exposure of optical receivers to direct sunlight could degrade the system performance and damage light-sensitive photo-detectors permanently. We investigate the average probability of the exposure of optical receiver to direct sunlight in FSO-based wireless mobile communication networks. We first estimate the probability of exposure to direct sunlight in open areas and then extend the theoretical analysis to the urban areas where the direct sunlight can be blocked by buildings. The validity of the analyses is evaluated through Monte Carlo simulations over a virtual city. The results show that the probability of exposure to direct sunlight ranges from 10−6 to 10−2, depending upon the receiver's field-of-view (FoV), latitude, average building heights, and the height of base stations (BSs). We also find out that the probabilities increase with the receiver's FoV to the power of 1.8 when the receiver's FoV is larger than the angular diameter of the sun. In urban areas, the probability decays exponentially with the average height of buildings exceeding the half of the BS height. The results also show that the probability rises with the BS height to the power of ∼2.6 under the same conditions. Finally, we estimate the outage time of FSO-based wireless mobile communications occurring by the exposure to direct sunlight. When the receiver's FoVs are 1 and 10 degrees, the outage times are estimated to be
PubDate: THU, 30 JAN 2025 09:17:52 -04
Issue No: Vol. 17, No. 2 (2025)
- Shot-Noise Limited, 10 MHz Swept-Source Optical Coherence Tomography for
Retinal Imaging
Authors: Sacha Grelet;Alejandro Martinez Jimenez;Patrick B. Montague;Adrian Podoleanu;
Pages: 1 - 5
Abstract: Akinetic swept-sources are essential for high-speed optical coherence tomography (OCT) imaging. Time-stretched supercontinuum (TSSC) lasers have proven to be efficient for multi-MHz swept-sources. However, lack of low-noise broadband lasers and of large dispersion devices in the water low-absorption band at 1060 nm have limited the biomedical applications of TSSC lasers. In this letter, an approach to tune the wavelength around 1050 nm over 90 nm with low-noise at 10 MHz is presented. This is based on all-normal dispersion (ANDi) supercontinuum dynamics, and employs a long chirped fiber Bragg grating (CFBG) to time-stretch a broadband pulse with a duty cycle of 93% . Retinal images are demonstrated, with a sensitivity of 84 dB - approaching the shot noise limit. We believe this high-speed low-noise swept-source will greatly promote the development of OCT techniques for biomedical applications.
PubDate: MON, 27 JAN 2025 09:18:37 -04
Issue No: Vol. 17, No. 2 (2025)
- Dissipative Soliton Generation in a Phase-Biased All-PM Fiber Oscillator
in the Normal-Dispersion Regime
Authors: Yuxian Zhang;Guanyun Ding;Guanyu Liu;
Pages: 1 - 7
Abstract: We numerically and experimentally demonstrate a phase-biased fiber oscillator with all-polarization-maintaining (all-PM) fibers. Through theoretical analysis, it is demonstrated that incorporating a non-reciprocal phase shifter improves the self-starting capability of the designed fiber laser. Moreover, the phase shifter in the all-PM laser configuration helps boost the repetition rate and further enhances the environmental stability. Numerical simulations are conducted for the proposed fiber laser operating in the normal-dispersion regime to investigate the spectral and temporal characteristics and the build-up dynamics. Experimentally, by manipulating the separation of the intra-cavity grating pair for dispersion compensation, this simple and novel Ytterbium-doped fiber laser delivers ultrashort pulses featuring a pulse duration of 1.81 ps, operating at a repetition rate of 44.4 MHz in the 1030 nm band. The delivered pulses are compressed externally using a grating pair, achieving a minimum pulse duration of 174 fs. We believe the proposed fiber oscillator provides a robust pulsed light source for numerous optical applications such as micromachining or optical frequency comb generation.
PubDate: MON, 27 JAN 2025 09:18:36 -04
Issue No: Vol. 17, No. 2 (2025)
- Measurement Research of Free-form Lens Optical Parameters Based on
Transmission Fringe Deflectometry
Authors: Xiaoxiao Wei;Xiaobing He;Zhenqiu Dai;Hao Zhang;
Pages: 1 - 8
Abstract: This paper presents a measurement system based on the transmission fringe deflectometry, which is designed to facilitate the rapid attainment of the free-form lens optical parameters, including spherical power, cylindrical power, and prismatic power. In this paper, we analyze the principle of transmission fringe deflectometry. The key technology, camera calibration, and phase unwrapping techniques are introduced in detail. A single-focus lens is given to demonstrate the validity of the proposed fringe deflection algorithm. Then the optical parameters calculation models of free-form lens, such as progressive lens, is presented and the detection results are given. Moreover, the results of the proposed fringe deflection algorithm are in close agreement with those obtained from simulations and the FFV interferometer. The error of free-form lens measured in this paper is less than 0.02D. The experimental outcomes validate the efficacy of the method, suggesting the potential for its application in the mass measurement of optical parameters for free-form lenses.
PubDate: FRI, 24 JAN 2025 09:16:37 -04
Issue No: Vol. 17, No. 2 (2025)
- Tunable Multi-Band Linear Frequency Modulated Waveforms Generation Based
on Self-Subharmonic Modulating of Optically Injected Semiconductor Laser
Authors: Jiachen Yu;Yiying Gu;Pengyuan Huang;Shuai Zu;Jiaqi Wang;Xiaozhou Li;Mingshan Zhao;Jingjing Hu;
Pages: 1 - 7
Abstract: A tunable multi-band linear frequency modulated microwave waveform generating system based on photonic approach is proposed and experimentally demonstrated. In this system, a semiconductor laser is optically injected in period-one oscillation state. The optical injection signal, modulated by the period-one signal via a photodetector, subharmonically modulates the laser, enhancing waveform stability. The modulated laser period is set as an integer multiple of cavity delay to approach Fourier domain mode-locking, simultaneously boosting signals across frequencies and times. The generated waveform can be tuned to generate either a unidirectional chirped or a bidirectional reciprocal chirped linear frequency modulated signal, and its center frequency and bandwidth can be easily adjusted.
PubDate: THU, 23 JAN 2025 09:17:25 -04
Issue No: Vol. 17, No. 2 (2025)
- Optimization of Inversion Probability Tunable Sequence Phase Modulation
for SBS Suppression in Fiber System
Authors: Qianhe Shao;Yifeng Yang;He Wang;Haowei Xia;Jingshuai Ma;Chenxiang Qian;Junqing Meng;
Pages: 1 - 12
Abstract: Phase modulation optical spectral broadening has been widely used as an effective stimulated Brillouin scattering suppressing scheme in narrow linewidth fiber amplifiers. In particular, tunable inversion probability sequence (p-tunable sequence) phase modulation effectively optimizes the spectral envelope, improving the SBS threshold in a monolithic narrow linewidth fiber amplifier. This paper theoretically and experimentally investigates the SBS suppression capability of p-tunable phase modulation. Firstly, we introduce a theoretical model to illustrate, for the first time, the temporal and spectral properties of light waves that have been phase-modulated by a p-tunable sequence. An optimization scheme for parameter selection of p-tunable sequence phase modulation is established by calculating the SBS threshold. Meanwhile, we establish a three-stage fiber amplifier system with p-tunable phase modulation to verify our theory. The output power is 2390 W with an FWHM optical linewidth of 10 GHz. Compared to the pseudo-random binary sequence (PRBS) case, this scheme increases the output power by 700 W at 10 GHz FWHM optical linewidth.
PubDate: THU, 23 JAN 2025 09:17:23 -04
Issue No: Vol. 17, No. 2 (2025)
- Cryophotonics: Experimental Validation of a SOA Model Down to Cryogenic
Temperatures
Authors: Maeva Franco;Lydia Kacel;Edwin Fontenelle;Pascal Morel;Thierry Rampone;Arnaud Gardelein;Ammar Sharaiha;
Pages: 1 - 9
Abstract: Cryophotonics is a promising way of boosting state-of-the-art photonic components using cryogenic temperatures. In this work, in addition to confirm our experimental results with measurements on another component, we present a theoretical analysis of SOA behavior at cryogenic temperatures. Based on the obtained experimental results, we expand the SOA model range by introducing temperature dependence on the main SOA physical parameters such as band gap energy level, recombination coefficients, internal losses and effective electron and holes masses. The model is applicable over a wide temperature range from ambient down to cryogenic temperatures. A qualitative agreement is found between simulations and experiments. The comparisons are given down to 70 K in terms of gain spectrum, saturation output power and noise figure which demonstrate the effectiveness of the model.
PubDate: WED, 22 JAN 2025 09:17:01 -04
Issue No: Vol. 17, No. 2 (2025)
- Hybrid Semiconductor Plasmonic Lasers for Biochemical Sensing: Theory and
Design
Authors: Shayan Saeidi;Jens H. Schmid;Pavel Cheben;Pierre Berini;
Pages: 1 - 12
Abstract: An electrically driven InP-based Fabry-Perot biochemical sensing laser is proposed and analyzed. The design incorporates a sensing area on top of the laser to alter its characteristics and operates in a hybrid plasmonic-semiconductor lasing mode. Our device is designed for an etch-free III-V (InP) based stack, where lateral confinement of the hybrid mode is ensured by a thin gold (Au) strip on a thin indium tin oxide (ITO) strip. We optimize the waveguide geometry to produce maximum sensitivity while having compensable loss. Our investigation centers on three laser characteristics that are affected by the sensing fluid and that could serve as measurands: lasing wavelength, threshold current, and power-current slope efficiency. We determine the sensitivity of each measurand, assess the potential noise sources, and the limit of detection (LoD) associated with them. Our calculations indicate that the proposed biosensor can achieve LoDs as low as 10−5 RIU when employing the threshold current as the measurand.
PubDate: TUE, 21 JAN 2025 09:16:30 -04
Issue No: Vol. 17, No. 2 (2025)
- Meijer-G Function With Continued Product and Integer Exponent: Performance
of Multi-Aperture UOWC System Over EGG Turbulence
Authors: Arvind Kumar;Nikumani Choudhury;Jayendra N. Bandyopadhyay;S. M. Zafaruddin;
Pages: 1 - 15
Abstract: Signal transmission over underwater optical wireless communication (UOWC) experiences the combined effect of oceanic turbulence and pointing errors statistically modeled using the sum of two Meijer-G functions. There is a research gap in the exact statistical analysis of multi-aperture UOWC systems that use selection combining diversity techniques to enhance performance compared to single-aperture systems. In this paper, we develop a general framework for the continued product and positive integer exponent for the sum of Meijer-G functions to analyze the exact statistical performance of the UOWC system in terms of multivariate Fox-H function for both independent and non-identically distributed (i.ni.d.) and independent and identically distributed (i.i.d.) channels. We also approximate the performance of a multi-aperture UOWC system with i.i.d. channels using the single-variate Fox-H function. Using the generalized approach, we present analytical expressions for average bit-error rate (BER) and ergodic capacity for the considered system operating over exponential–generalized gamma (EGG) oceanic turbulence combined with zero-boresight pointing errors. We also develop asymptotic expressions for the average BER at a high signal-to-noise (SNR) to capture insights into the system's performance. Our simulation findings confirm the accuracy of our derived expressions and illustrate the impact of turbulence parameters for i.ni.d. and i.i.d. models for the average BER and ergodic capacity, which may provide a better estimate for the efficient deployment of UOWC.
PubDate: TUE, 24 DEC 2024 09:18:40 -04
Issue No: Vol. 17, No. 2 (2024)
