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- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2019 IEEE International Conference on Imaging Systems and Techniques (IST) - Abu Dhabi, United Arab Emirates (2019.12.9-2019.12.10)] 2019 IEEE International Conference on Imaging Systems and Techniques (IST) - A Multi-frequency WMS Method for Tunable Diode Laser Absorption Spectroscopy Tomography
摘要： In this paper, we investigate the properties of transmission links amplified by phase-sensitive amplifiers (PSAs). Using an analytic description, we explain the principles enabling improved sensitivity compared to conventional links amplified by phase-insensitive amplifiers (PIAs) and mitigation of nonlinear transmission distortions. We demonstrate these features using numerical simulations, and in particular, we show the possibility of efficiently mitigating both self-phase modulation (SPM)-induced distortions and nonlinear phase noise (NLPN) if the link dispersion map is optimized. The properties of the noise on signal and idler are important and to enable NLPN mitigation, the noise must be correlated at the link input. We investigate the role of the dispersion map in detail and show that in a link with standard single mode fiber (SSMF) the optimum dispersion map for efficient nonlinearity mitigation corresponds to precompensation of an amount equal to the effective loss length. Furthermore, we experimentally demonstrate both improved sensitivity and mitigation of nonlinearities in a 105 km PSA-amplified link transmitting 10 GBd 16-ary quadrature amplitude modulation (16QAM) data. We measure a combined effect allowing for more than 12 dB larger span loss in a PSA-amplified link compared to a conventional PIA-amplified link to reach the same bit error ratio (BER) of 1 × 10?3.
关键词： Fiber nonlinearity mitigation,phase-conjugated twin waves,fiber optical parametric amplifiers (FOPAs),optical amplifiers,phase-sensitive amplifiers (PSAs),optical fiber communication
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - All-Fiber Bi-Doped Laser Continuously Tunable from 1317–1375nm
摘要： Exploring the new wavelength bands is of great importance for many different applications such as medicine, astronomy, material processing, defence and optical fiber communication. Ytterbium (Yb), Erbium (Er), and Thulium (Tm) or Holmium (Ho)- doped fibers covers the wavelength bands around 1, 1.5 and 2μm, respectively. However, the band between Yb and Er is mostly not covered by the rare earth (RE)-doped silica fibers. Recent years, there is a growing interest to use Bi-doped fibers with different host materials such as aluminosilicate, phosphosilicate and germanosilicate to explore the wavelength band from 1150-1500nm. Also, Bi-doped germanosilicate fibers with a high concentration of germanium (up to 50mol%) were used to cover the band from 1600-1800nm. Many optoelectronic devices including amplifiers, lasers, amplified spontaneous emission (ASE) sources and pulsed lasers were reported using Bi-doped fibers [1-3]. However, less work is being done to develop tunable Bi-doped fiber lasers. Using a Bi-doped germanosilicate fiber a tunable laser operating from 1360 to 1510nm was reported. The cavity was formed by a loop reflector and an external plane diffraction grating [4]. In this paper, we demonstrate a tunable laser operating in 1317 to 1375nm band using Bi-doped phosphosilicate fiber fabricated in-house using modified chemical vapour deposition (MCVD)-solution doping technique. The fiber has a core and clad diameter of 9μm and 125μm, respectively. The index difference (Δn) between the core and clad was around 0.004. The absorption at 1270nm pump wavelength was 0.57dB/m.
关键词： Bi-doped fiber,optical fiber communication,tunable laser,phosphosilicate fiber
更新于2025-09-16 10:30:52
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Laser Phase Noise Tolerance of Uniform and Probabilistically-shaped QAM Signals for High Spectral Efficiency Systems
摘要： We numerically and experimentally investigate the laser phase noise tolerance of probabilistically shaped (PS) and uniformly shaped (US) quadrature amplitude modulation (QAM) signals. In the simulations, we compare PS-64QAM to US-16QAM, PS-256QAM to US-64QAM, and PS-1024QAM to US-256QAM under the same information rate (IR). We confirm that a sufficient shaping gain is observed with narrow linewidth lasers, whereas degradation of the shaping gain is clearly observed when large phase noise and high order modulation formats are assumed. We also evaluate the pilot ratio dependency of the required optical signal-to-noise ratio at the forward error correction limit and the achievable information rate. Additionally, we compare the performance of two types of CPR updating schemes: updating phase estimation at only the pilot symbol or at all symbols.
关键词： Digital coherent,high order quadrature amplitude modulation,laser phase noise,probabilistic shaping,optical fiber communication
更新于2025-09-16 10:30:52
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Advanced DSP for Coherent Optical Fiber Communication
摘要： In this paper, we provide an overview of recent progress on advanced digital signal processing (DSP) techniques for high-capacity long-haul coherent optical fiber transmission systems. Not only the linear impairments existing in optical transmission links need to be compensated, but also, the nonlinear impairments require proper algorithms for mitigation because they become major limiting factors for long-haul large-capacity optical transmission systems. Besides the time domain equalization (TDE), the frequency domain equalization (FDE) DSP also provides a similar performance, with a much-reduced computational complexity. Advanced DSP also plays an important role for the realization of space division multiplexing (SDM). SDM techniques have been developed recently to enhance the system capacity by at least one order of magnitude. Some impressive results have been reported and have outperformed the nonlinear Shannon limit of the single-mode fiber (SMF). SDM introduces the space dimension to the optical fiber communication. The few-mode fiber (FMF) and multi-core fiber (MCF) have been manufactured for novel multiplexing techniques such as mode-division multiplexing (MDM) and multi-core multiplexing (MCM). Each mode or core can be considered as an independent degree of freedom, but unfortunately, signals will suffer serious coupling during the propagation. Multi-input–multi-output (MIMO) DSP can equalize the signal coupling and makes SDM transmission feasible. The machine learning (ML) technique has attracted worldwide attention and has been explored for advanced DSP. In this paper, we firstly introduce the principle and scheme of coherent detection to explain why the DSP techniques can compensate for transmission impairments. Then corresponding technologies related to the DSP, such as nonlinearity compensation, FDE, SDM and ML will be discussed. Relevant techniques will be analyzed, and representational results and experimental verifications will be demonstrated. In the end, a brief conclusion and perspective will be provided.
关键词： coherent detection,neural network,space division multiplexing,digital signal processing,nonlinearity compensation,machine learning,optical fiber communication,equalization
更新于2025-09-16 10:30:52
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Phase Noise Measurements and Performance of Lasers with Non-white FM Noise for Use in Digital Coherent Optical Systems
摘要： We measure the FM noise power spectral density of quantum-dot mode-locked lasers (QD-MLLs) and compare this to their measured linewidths as predictors of performance in a digital coherent system. We explain our observations in terms of the non-Lorentzian line shape of the source wherein linewidth is determined by the low frequency part of its FM noise. Investigation of system performance with simulations based on the measured phase sequences and back-to-back coherent transmission experiments, show that QD-MLLs with linewidths of several MHz can have comparable performance to that of a laser with only a few hundreds of kHz of Lorentzian linewidth, due to the non-white part of their FM noise. We show that spectral linewidths of lasers with similar spectral properties can underestimate their performance in coherent systems, regardless of the linewidth measurement technique used. We propose a “Lorentzian-equivalent linewidth” measure to characterize lasers with non-white FM noise and to estimate their impact in digital coherent optical systems. This measure is obtained from phase variations at frequencies higher than typical frequencies often used to characterize lasers with white FM noise, and comparable to the system baud. The proposed measure is shown to be a better predictor of system performance than the measured linewidth, for lasers with non-white FM noise. The impact of non-white FM noise on the optimization of carrier phase recovery and system performance is also discussed.
关键词： diode lasers,Coherent communication,optical fiber communication,mode-locked lasers
更新于2025-09-12 10:27:22
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Intelligent 2-dimensional soft decision enabled by k-means clustering for VCSEL-based 112-Gbps PAM-4 and PAM-8 optical interconnection
摘要： In this work, we proposed an intelligent 2-dimensional soft decision (2D SD) enabled by k-means clustering, for vertical-cavity surface-emitting laser (VCSEL) based 112-Gbps PAM-4 and PAM-8 optical interconnection. At high modulation speed, VCSEL based link suffers from severe level nonlinearity, level-dependent noise and inter-symbol interference (ISI). For characterizing the above-mentioned three distortions, 2D signaling is performed through time-slotted mapping of PAM. Without extra requirement of Monte Carlo approach, channel conditional probability density function (PDF) can be intelligently estimated using inline data, thanks to 2D k-means machine learning. Thus, improved precision of log likelihood ratio (LLR) can be realized by additional consideration of nonlinearity, level-dependent noise and ISI. Both simulations and experiments have been carried out for proof-of-concept investigations on VCSEL and multimode fiber (MMF) links. 112-Gbps PAM-4 and PAM-8 signaling have been experimentally realized using a commercial-product-level VCSEL with 100-m MMF transmission. The results indicate significant improvement of the proposed k-means 2D SD without training using prior-known sequences.
关键词： multidimensional signal processing,optical fiber communication,Decision support systems,machine learning
更新于2025-09-12 10:27:22
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Design on Program-Controlled Initiation System of the SCB explosive devices Based on Optical Fiber Communication
摘要： A control system for Semiconductor Bridge explosive devices is designed based on optical fiber Communication, which can make the explosive devices perform better in the complex electromagnetic environment. By the combination of programmable bus controller, ignition unit and the optical fiber communication, the ignition of the explosive devices in chronological order could be realized. After the system design was completed, the major function and anti-electromagnetic interference capability were tested. The results indicated that the system had remote-control ability, high reliability, high security and good electromagnetic compatibility. The system can be used in more complicated electromagnetic environment than the conventional initiating explosive devices.
关键词： programmable bus controller,ignition unit,electromagnetic compatibility,Semiconductor Bridge explosive devices,optical fiber communication
更新于2025-09-12 10:27:22
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Unified Formalism for Erbium-Doped Fiber Amplifiers and Lasers
摘要： A comprehensive and integrated exact analytical formalism is presented for erbium-doped fiber amplifiers and lasers (EDFALs) in one single configuration based on solutions of a system of rate and propagation equations represented by a homogenously broadened four band transition scheme while incorporating amplified spontaneous emission and excited state absorption effects. The formalism, under steady-state conditions, concurrently provides considerable insight into physical characteristics underlying phenomena pertinent to EDFALs and allows precise evaluation of behavior exhibited by EDFALs through a judicious selection of pump intensity and fiber length in standard eye-safe low-erbium concentration uniformly doped mono-mode silica glass fibers in co- and counter- propagating directions appropriate to signal, pump and ASE regimes.
关键词： analytical modeling,erbium-doped fiber amplifiers,optical fiber communication,erbium-doped fiber lasers
更新于2025-09-11 14:15:04
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The Impact of Local Oscillator Frequency Jitter and Laser Linewidth to Ultra High Baud Rate Coherent Systems
摘要： Through theoretical analysis and simulation, we investigate the system impact due to a sinusoidal jitter tone and the resultant local oscillator (LO) laser linewidth requirement in ultra-high baud rate and long distance coherent optical systems. We also carried out experiments in 64Gbaud, dual-polarization (DP)-16QAM systems to verify the theoretical analysis and simulation. We have also obtained a jitter interference tolerance mask to qualify LO lasers. A jitter tone with a frequency lower than ~1MHz has a higher tolerance since it generally causes constant frequency or phase shift, which can be tracked by a receiver DSP. For a jitter tone with a frequency higher than ~1MHz, the tolerance becomes much tighter since the tone will affect laser lineshape and induce equalizer-enhanced phase noise (EEPN). Consequently, a jitter tone in the higher frequency region could severely affect the system performance. Theoretical analysis and numerical result illustrate that EVM2 due to the effect of laser linewidth and a sinusoidal jitter tone is proportional to the weighted sum of [Δν × Bs × L] and [Δfpp×Bs × L]2, where Δν is the laser linewidth, Bs is the baud rate, Δfpp is the laser peak-to-peak frequency deviation due to a sinusoidal jitter tone, and L is the fiber transmission length. This result is applicable for all orders of QAM constellations. The implication to future 100 Gbaud and beyond systems is delineated.
关键词： laser noise,Optical fiber communication,coherent communication
更新于2025-09-11 14:15:04
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[IEEE 2019 International Conference on Robots & Intelligent System (ICRIS) - Haikou, China (2019.6.15-2019.6.16)] 2019 International Conference on Robots & Intelligent System (ICRIS) - Research on Security Threats and Protection Strategies of Optical Fiber Communication
摘要： Natural factors, human factors and technical factors have many security threats to optical fiber communication with the improvement of informatization. The security threat of optical fiber communication is analyzed. The integration of military and civilian, the combination of field and fixed, the improvement of the equipment performance, and the establishment of standardized guarantee mechanism and operational procedures need to be strengthened is proposed to improve the protection capability of the optical fiber communication network.
关键词： Security Protection,Optical Fiber Communication,Security Threat
更新于2025-09-11 14:15:04