- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A Coherent Homodyne TO-Can Transceiver as Simple as an EML
摘要： The introduction of low-cost coherent signal reception in optical telecommunications is one of the great challenges since its opto-electronic sub-systems are associated to a high degree of complexity. In this work we propose a disruptive approach: the re-use of widely deployed direct-detection technology for simultaneous coherent homodyne reception and transmission. We first show that an externally modulated laser (EML) is sufficient to perform both, coherent reception and transmission functionality. Second, we prove that homodyne detection applies to the EML-based scheme in virtue of an injection-locked local oscillator, which for low input power levels is pulled to the optical carrier frequency of the incident data signal. The proposed methodology for coherent reception enables a greatly simplified transceiver as optical-layer hardware. As we will demonstrate it just requires single fiber access, a single radio frequency port and can be implemented in a transistor-outline package. Full-duplex transmission with coherent homodyne reception is experimentally validated, showing 2.5 Gb/s transmission over 27.5 km reach and a loss budget of 28 dB, and coherent Gigabit Ethernet connectivity – without use of optical-layer digital signal processing functions.
关键词： Externally modulated laser,Optical signal detection,Optical communication terminals,Homodyne detection,Optical fiber communication
更新于2025-09-19 17:15:36
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New binary particle swarm optimization on dummy sequence insertion method for nonlinear reduction in optical direct-detection orthogonal frequency division multiplexing system
摘要： In the paper, a novel new binary particle swarm optimization method based on dummy sequence insertion is proposed and experimentally demonstrated in the IM-DD optical orthogonal frequency division multiplexing (OOFDM) system. This technique can mitigate nonlinearity of OOFDM system without any channel side information. Experimental results demonstrate that compared to the original scheme, the improvement in the receiver sensitivity by the proposed scheme is 1.9 dB and 3.2 dB with launch powers of 2 dBm and 8 dBm, respectively, at the BER of FEC 3.8 × 10^{-3} after transmission over 100-km standard single-mode fiber. At a complementary cumulative distribution function of 10^{-4}, the PAPR of OFDM signal can be reduced about 2.8 dB by using the proposed scheme, while the receiver-side hardware is the same as the origin.
关键词： Optical fiber communication,Particle swarm optimization (PSO),Dummy sequence insertion (DSI),Orthogonal frequency division multiplexing (OFDM)
更新于2025-09-19 17:15:36
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Low complexity soft-decision Viterbi algorithm (SOVA) for IM/DD 56 Gbps PAM-4 system
摘要： In this paper, a soft-decision Viterbi algorithm (SOVA) combined with low-density parity check (LDPC) is investigated to achieve high chromatic dispersion tolerance and alleviate the high OSNR requirement in pulse amplitude modulation 4-level (PAM-4) systems. To reduce complexity increase over a maximum likelihood sequence equalizer (MLSE), we propose a non-binary SOVA algorithm combining the conventional SOVA and the hard decision Viterbi algorithm (VA). To achieve low complexity, only one competing path in a state and time index is used to update reliability. After the updating process, reliabilities that remain to be un-updated are set to a fixed value according to the hard decided VA output. Also, the proposed algorithm generates reliability scalars instead of a reliability vector. The proposed algorithm was verified experimentally in a 56 Gbps PAM-4 system with the transmission distance of 20 km. The results demonstrates that the proposed algorithm has OSNR gain of 0.3 dB over conventional SOVA with lower complexity at the BER of 10-6.
关键词： IM/DD,MLSE,optical fiber communication,LDPC,PAM-4
更新于2025-09-19 17:15:36
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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) - Direct Quantum Error Detection in Spatially Multiplexed Transmission
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： phase-sensitive amplifiers (PSAs),Fiber nonlinearity mitigation,optical amplifiers,optical fiber communication,phase-conjugated twin waves,fiber optical parametric amplifiers (FOPAs)
更新于2025-09-19 17:13:59
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[IEEE 2018 International Conference Laser Optics (ICLO) - St. Petersburg (2018.6.4-2018.6.8)] 2018 International Conference Laser Optics (ICLO) - Spectroscopic and laser properties of Tm <sup>3+</sup> ions optical centers in CaF2-YF3:Tm <sup>3+</sup> solid solutions
摘要： In this paper, we review recent progress on space division multiplexed (SDM) transmission and our proposal of dense SDM (DSDM) with more than 30 spatial channels toward capacities beyond petabit/s. Furthermore, we discuss the requirements for realizing long-haul DSDM transport systems using multicore and/or multimode fiber, including power and space efficient amplification schemes, the use of fibers with large effective areas and transmission lines with low intercore crosstalk, low differential mode delay (DMD), and low mode dependent loss (MDL). Graded index heterogeneous 12-core × 3-mode fiber with low crosstalk, low DMD, and low MDL, parallel multiple-input and multiple-output signal processing, low mode dependent gain Erbium-doped fiber amplifiers, and MDL equalization technologies are significant as regards extending the reach of multicore and multimode transmission. We review our long-distance transmission experiment on polarization-division multiplexed 16-quadrature amplitude modulation signaling over 12-core × 3-mode fiber.
关键词： optical communication systems,optical fibers,optical fiber communication,spectral efficiency,space division multiplexing,Digital signal processing (DSP)
更新于2025-09-19 17:13:59
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Rationality Modeling of 3D Scanning Image of Digital Print Laser Based on Block Matching Texture Information Repair
摘要： We experimentally investigate mutual information and generalized mutual information for coherent optical transmission systems. The impact of the assumed channel distribution on the achievable rate is investigated for distributions in up to four dimensions. Single channel and wavelength-division multiplexing (WDM) transmission over transmission links with and without inline dispersion compensation are studied. We show that for conventional WDM systems without inline dispersion compensation, a circularly symmetric complex Gaussian distribution is a good approximation of the channel. For other channels, such as with inline dispersion compensation, this is no longer true and gains in the achievable information rate are obtained by considering more sophisticated four-dimensional (4D) distributions. We also show that for nonlinear channels, gains in the achievable information rate can also be achieved by estimating the mean values of the received constellation in four dimensions. The highest gain for such channels is seen for a 4D correlated Gaussian distribution.
关键词： mutual Information,digital communication,fiber nonlinear optics,optical fiber communication,Channel models
更新于2025-09-19 17:13:59
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[IEEE IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium - Yokohama, Japan (2019.7.28-2019.8.2)] IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium - Characterization of double-bounce scattering in RVoG scenarios using controlled HR-PolTomSAR experiments
摘要： We experimentally investigate mutual information and generalized mutual information for coherent optical transmission systems. The impact of the assumed channel distribution on the achievable rate is investigated for distributions in up to four dimensions. Single channel and wavelength-division multiplexing (WDM) transmission over transmission links with and without inline dispersion compensation are studied. We show that for conventional WDM systems without inline dispersion compensation, a circularly symmetric complex Gaussian distribution is a good approximation of the channel. For other channels, such as with inline dispersion compensation, this is no longer true and gains in the achievable information rate are obtained by considering more sophisticated four-dimensional (4D) distributions. We also show that for nonlinear channels, gains in the achievable information rate can also be achieved by estimating the mean values of the received constellation in four dimensions. The highest gain for such channels is seen for a 4D correlated Gaussian distribution.
关键词： fiber nonlinear optics,optical fiber communication,digital communication,Channel models,mutual Information
更新于2025-09-19 17:13:59
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Secure 100 Gb/s IMDD Transmission Over 100 km SSMF Enabled by Quantum Noise Stream Cipher and Sparse RLS-Volterra Equalizer
摘要： In this paper, we have experimentally demonstrated a secure 100 Gb/s intensity-modulation and direct-detection transmission over 100 km standard single-mode fiber (SSMF) based on quantum noise stream cipher (QNSC) for the first time. The original 4-level pulse-amplitude modulation (PAM4) data is mapped to M-level data sequence randomly, and quantum noise such as the generated amplified spontaneous emission noise and the shot noise in the channel can mask these adjacent signal levels. The legitimate receiver needs to distinguish not M-level encrypted data but 4-level data with the shared key. In our scheme, a calculated detection failure probability of 98.72% is achieved. Apparently, more quantum noise contributes to higher security but the worse signal to noise ratio. To balance algorithm complexity, transmission performance and security performance, a sparse regularization based on recursive least square (RLS) algorithm is proposed and firstly used in Volterra equalizer. To eliminate the power fading induced by fiber dispersion, a dual-drive Mach-Zehnder modulator is used to achieve single-sideband modulation, and no dispersion compensation is required. By these means, 100Gb/s PAM4-QNSC signal transmission over 100 km SSMF with the bit error rate (BER) below the 7% overhead hard-decision forward error correction threshold of 3.8x10-3 is achieved, and >59% complexity reduction of Volterra equalizer is realized. Moreover, the measured BER of 150 Gb/s PAM8-QNSC signal transmission over 50 km SSMF could go below the 20% overhead soft-decision forward error correction threshold of 2.0×10-2. The results validate that the proposed scheme is effective to realize low-cost, high-speed (>100 Gb/s), and secure optical fiber transmission in the data center.
关键词： quantum noise cipher stream,Optical fiber communication,sparse RLS-Volterra equalizer
更新于2025-09-19 17:13:59
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[IEEE 2019 International Vacuum Electronics Conference (IVEC) - Busan, Korea (South) (2019.4.28-2019.5.1)] 2019 International Vacuum Electronics Conference (IVEC) - Notice of Removal: Compact Waveguide Coupler with Broadband and High Coupling Flatness
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 International Conference on Electrical Engineering and Informatics (ICEEI) - Bandung, Indonesia (2019.7.9-2019.7.10)] 2019 International Conference on Electrical Engineering and Informatics (ICEEI) - Rooftop Photovoltaic Hosting Capacity Assessment: A Case Study of Rural Distribution Grids in Yogyakarta, Indonesia
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