2010, 8(9) Column
Chinese Optics Letters 第8卷 第9期
2010-09-0815.pdf
Enabling Science High-Speed Optical Fiber optics Enabling Science High-Speed Optical Fiber optics An adaptive polarization mode dispersion (PMD) compensation experiment is reported in a 40-Gb/s phase shaped binary transmission (PSBT) communication system, with the use of a new digital signal processor (DSP)-based optical PMD compensator. PMD tolerance is found to be enhanced by 8 ps after PMD compensation with 1-dB optical signal-to-noise ratio (OSNR) penalty. Under the condition of fast change of states of polarization up to 85 rad/s in the fiber link, the performance of our PMD compensator undergoes the bit error ratio (BER) test for as long as 10 h.
光纤通信系统 相位整形二进制传输 偏振模色散补偿 偏振模色散容忍度 060.0060 Fiber optics and optical communications 230.0230 Optical devices 250.0250 Optoelectronics A method of multi-channel receiving for high bit rate heterodyne direct-detection optical orthogonal frequency-division-multiplexing (OOFDM) system is proposed to reduce the sampling rate demand of analog-to-digital converter (ADC). The sampling rate of ADCs can be reduced to 1/N that of the original signal bandwidth in an N-channel receiving system. Aided by a succeeding digital signal processing (DSP) at the receiver, aliasing free signal can be recovered. A back-to-back experimental result is given for a 4-channel system, based on which, a down conversion process for heterodyne can be reduced. The signal rebuilding algorithm is given and analyzed in its complexity and noise tolerance.
光正交频分复用 采样 多通道接收 060.0060 Fiber optics and optical communications 060.4080 Modulation 060.4230 Multiplexing We summarize several novel schemes to generate multi-level modulation formats for high capacity transmission system with high spectral efficiency. We show that multi-level 8QAM, 16QAM, 32QAM, and 64QAM (QAM: quatlrature amplitude modulation) optical signals can be generated by commercial optical and electrical devices. Employing these multilevel modulation formats, we have realized PDM-8QAM (PDM: polarization division multiplexing) 32 Tb/s and PDM-36QAM 64-Tb/s signals transmission over 580- and 320-km fibers, respectively.
调制格式 相干探测 超大容量 光通信 8QAM 32QAM 64QAM 250.0040 Detectors 250.4110 Modulators 250.4480 Optical amplifiers 250.5530 Pulse propagation and temporal solitons 190.4370 Nonlinear optics, fibers We provide a review of our recent 100-Gb/s, high spectral efficiency (SE) experiment targeting transoceanic and regional undersea transmission distances. We demonstrated that simple pre-filtering at the transmitter together with a maximum a posteriori probability (MAP) detection algorithm can significantly improve SE. We transmitted 96×100-Gb/s pre-filtered polarization division multiplexed return-to-zero quadrature phase shift keyed (PDM-RZ-QPSK) channels with 300% SE over 10608 km using 52-km spans of 150-μm2 fiber and simple single-stage erbium-doped fiber amplifiers (EDFAs). We also achieved 400% SE over 4368 km using similar techniques.
光纤通信 相干通信 光通信 060.2330 Fiber optics communications 060.1660 Coherent communications 060.4510 Optical communications A novel 40-Gb/s constant envelope optical frequency shift keying (FSK) transmitter and the transmission characteristics are investigated both by simulation and experiment. Meanwhile, to increase the spectrum efficiency of FSK, we propose a novel optical minimum-shift keying (MSK) scheme and analyze its performance compared with other MSK schemes and other traditional modulation formats. Simulation and experimental results show that the novel FSK scheme could be a potential candidate for the future high speed transmission and label switching systems. And the novel MSK scheme deserves future deep research for its potential excellent performance.
光频移键控 光最小频移键控 060.2330 Fiber optics communications 060.2360 Fiber optics links and subsystems 060.4080 Modulation Using numerical simulations, the nonlinear transmission performance of polarization-division-multiplexed quadrature-phase-shift-keying (PDM-QPSK) coherent systems is studied. It is found that inter-channel cross-polarization modulation (XPolM) induced nonlinear polarization scattering can significantly degrade the transmission performance of PDM-QPSK coherent systems and change the perspective of dispersion management in optical coherent transmission systems. Some techniques to mitigate nonlinear polarization scattering in dispersion-managed PDM coherent transmission systems are discussed, including the use of time-interleaved return-to-zero (RZ) PDM formats, the use of periodic-group-delay PGD dispersion compensators, and the judicious addition of some polarization-mode-dispersion (PMD) in the transmission link. It is shown that if nonlinear polarization scattering can be well mitigated, a polarization multiplexed optical coherent transmission system with dispersion management could perform better than that without it.
光纤光通信 非线性偏振效应 交叉偏振调制 交叉相位调制 偏振复用 060.2330 Fiber optics communications 060.4370 Nonlinear optics, fibers 260.5430 Polarization We propose a novel advanced orthogonal modulation format dark return-to-zero frequency shift keying/differential phase shift keying (DRZ-FSK/DPSK) and its realization scheme. The DRZ-FSK/DPSK is generated by the combination of a 40-Gb/s return-to-zero (RZ) signal and a DRZ signal which is converted from the RZ using a semiconductor optical amplifier (SOA) based on nonlinear cross polarization rotation (XPR) and then re-modulated by high-bit-rate DPSK at 40 Gb/s. The feasibility of the scheme is experimentally demonstrated. Bit error rate (BER) results of the total 80-Gb/s DRZ-FSK/DPSK orthogonal modulation signal with a subsequent 100-km single-mode fiber (SMF) transmission link show its potential for future high-speed long-haul optical communication.
060.2330 Fiber optics communications 060.4080 Modulation Analysis of smooth phase modulation formats compared with conventional QPSK and BPSK using coherent detectionDownload:827次
Novel optical offset quadrature phase shift keying (OQPSK) and improved minimum-shift keying (MSK) modulation schemes to smooth optical phase hopping for high speed fiber optics transmission are proposed. Simulations have been done among the MSK, OQPSK, quadrature phase shift keying (QPSK), and binary phase-shift keying (BPSK) modulation formats at 40 Gb/s over 100-km transmission link using coherent detection. Simulation results present good performances to elevate chromatic dispersion tolerance and reduce the influence of nonlinear effects by adopting the smooth phase modulation formats. Inter-symbol interference decreases for the fast side-lobe property and tight spectrum as a result of avoding the π phase shift and reducing envelop fluctuation.
相位平滑调制 偏移四相相移键控 最小移频键控 060.2330 Fiber optics communications 060.4080 Modulation 060.5060 Phase modulation We propose and investigate a novel technique to realize non-return-to-zero (NRZ) to return-to-zero (RZ) format conversion of a multichannel 4-ary amplitude shift keying (4-ASK) signal. The proposed format converter composed of two modulators and a dispersion compensating fiber (DCF) is theoretically investigated using numerical simulation as basis. Research shows that a 4-channel 20-Gb/s NRZ-4-ASK signal can be converted to a RZ-4-ASK signal simultaneously without wavelength shifting and signal quality degradation, with the converted signal multiplexed to 40 Gb/s.
060.2330 Fiber optics communications 070.4340 Nonlinear optical signal processing 230.0250 Optoelectronics This paper presents a review on the recent progress of digital signal processing (DSP) in the high-speed optical transmission system using single-carrier based multi-level modulation formats. The principle of several digital phase and polarization tracking algorithms recently proposed and demonstrated for future spectrally-efficient optical transmission system are discussed in detail. A novel DSP-based interference mitigation algorithm for the single-ended coherent receiver has been included. Recent technology advance on transmitter-side DSP such as digital pulse-shaping, pre-equalization and digital nonlinear compensation has also been discussed.
光通信 数字信号处理 相干与统计光学 060.0060 Fiber optics and optical communications 030.0030 Coherence and statistical optics A phase pre-emphasis technique used in an all-optical sampling orthogonal frequency division multiplexing (AOS-OFDM) system is proposed and demonstrated. With the application of this technique, 50-Gb/s AOS-OFDM data are successfully transmitted over 20-km uncompensated single-mode fiber (SMF) with real-time direct-detection. The constructive interference effect between symbols is decreased with this technique.
全光采样正交频分复用 相位预加重 实时 060.2330 Fiber optics communications 060.4230 Multiplexing Phase pre-emphasis for PAPR reduction in optical OFDM systems based on OIDFT or time lensDownload:524次
Phase pre-emphasis is theoretically studied and introduced to reduce peak-to-average power ratio (PAPR) in optical orthogonal frequency division multiplexing (OFDM) systems. In intensity modulated (IM) systems, simulations show noticeable PAPR reductions: 4.14 dB (N = 16) and 15.48 dB (N = 512) in time lens-based OFDM, N is the number of subcarriers. An equation is developed to calculate phase values and is proved to be effective. Optical implementing methods are proposed and analyzed. In a time lens-based OFDM system, phase pre-emphasis reduces fiber nonlinearity and results in a 5.2-dB increase of launch power at the bit error rate (BER) of 10?6. Simulations also show similar PAPR reduction and fiber nonlinearity mitigation in optical inverse discrete Fourier transformer (OIDFT) based OFDM systems.
峰均比 正交频分复用 光纤通信 相位预加重 光纤非线性 060.4230 Multiplexing 060.4510 Optical communications 190.4370 Nonlinear optics, fibers A novel non-feedback precoder circuit for high-speed parallel optical differential quadrature phase shift keying (DQPSK) modulation is proposed. The alternative control signal is introduced in replacement of the conventional feedback one, which eliminates the speed limitation due to the electronic propagation delay. The proposed precoder consists of four differential encoders, an exclusive OR gate, a cross switch, and delay lines. It is demonstrated by a true pseudo random bit sequence (PRBS) transmission at 20 Gb/s.
光差分正交移相键控 光调制 光纤通信 060.2330 Fiber optics communications 060.5060 Phase modulation Construction of optimal 2D variable-weight optical orthogonal codes for high-speed OCDMA networksDownload:942次
A new construction method of two-dimensional (2D) variable-weight optical orthogonal codes (VWOOCs) is proposed for high-speed optical code-division multiple-access (OCDMA) networks supporting multiple qualities of services (QoS). The proposed codes have at most one-pulse per wavelength (AM-OPPW) property. An upper bound of the codeword cardinality of the 2D VWOOCs with AM-OPPW property is derived. It is then shown that the constructed codes have ideal correlation properties and optimal cardinality. Moreover, the code length and the bit-error-rate (BER) performance of the proposed codes are compared with those of the codes proposed previously.
二维 高速 光正交码 最优 变重量 060.1155 All-optical networks 060.2360 Fiber optics links and subsystems 060.4230 Multiplexing Blind frequency offset estimation based on cyclic prefix and virtual subcarriers in CO-OFDM systemDownload:990次
A new blind frequency offset estimation method based on cyclic prefix and virtual subcarriers in coherent optical orthogonal frequency division multiplexing (CO-OFDM) system is presented. It is able to estimate the fractional part and integral part of frequency offset at the same time. Its estimation range is about [?3.5 GHz, 3.5 GHz]. The influence of the integral frequency offset is comprehensively analyzed in COOFDM system. Its performances in the additive white Gaussian noise (AWGN) channel and the dispersive channel are investigated, respectively. Simulation results indicate that even in the dispersive channel, when the optical signal-to-noise ratio (OSNR) is low, it can still work very well.
盲估计 频偏 循环前缀 虚载波 060.0060 Fiber optics and optical communications 060.1660 Coherent communications 060.2330 Fiber optics communications 060.5060 Phase modulation A novel scheme to generate, transmit, and receive an optical orthogonal frequency division multiplexing (OFDM) continuous phase modulation (CPM) signal, which is combining minimum shift keying (MSK) coding with OFDM optical modulation, for downlink application in a 4×2.5-Gb/s wavelength division multiplexing (WDM) passive optical access network, is proposed and experimentally validated. We also realize wavelength remodulation for carrying upstream on-off keying (OOK) data to reduce the cost budget at the optical network unit. The experimental results show that the power penalties for the downlink and the uplink data after transmission over 25-km SMF-28 fiber are 0.1 dB and smaller than 0.4 dB, respectively.
光通信 无源光网络 正交频分复用 功率代价 060.2330 Fiber optics communications 060.2360 Fiber optics links and subsystems 060.4080 Modulation A distributed access scheme using optical add/drop multiplexers (OADMs) for long reach hybrid wavelength division multiplexing and time division multiplexing passive optical networks (WDM-TDM PONs) is proposed and demonstrated. Colorless operations are implemented by using commercially available reflective semiconductor optical amplifiers (RSOAs) at both the center office (CO) and the customer side. Four 1.25-Gb/s channels are successfully transmitted over 80-km single-mode fiber with four OADMs. The dynamic input power range of the RSOA is also investigated. Compared with traditional access schemes, the proposed scheme could cover the area along the feed fiber with no blind zone. The experimental results show that it could be an ideal solution for the next generation access networks.
无源光网络 光分插复用器 分布式接入 反射式半导体光放大器 060.0060 Fiber optics and optical communications 060.2330 Fiber optics communications 060.4250 Networks 060.4254 Networks, combinatorial network design A scheme for photonic generation of ultra-wideband (UWB) pulses using a semiconductor optical amplifier (SOA) and an electro-absorber (EA) in parallel is proposed and numerically demonstrated. By adjusting the time delay between two pump signals incident into the SOA and the EA, we can obtain monocycle pulses with reversed polarities and different bandwidths. The proposed method is flexible in pulse shaping and easy in practical optimization.
超宽带 半导体光放大器 电吸收调制器 350.4010 Microwaves 250.5980 Semiconductor optical amplifiers 070.4340 Nonlinear optical signal processing Optical frequency shift keying (FSK) homodyne detection utilizing image rejection in FSK/amplitude shift keying (ASK) re-modulation wavelength-division-multiplexed passive optical network (WDM-PON) is proposed and demonstrated. Image rejection is adopted to achieve better performance. We show the result in back-to-back and 40-km distance respectively and apparent improvement is obtained in the latter situation by using image rejection. Several factors which affect the image rejection receiver are analyzed in order to find out the optimum parameters. Result shows that the presented scheme is suitable for super long reach access network, especially for future metro access network.
频移键控 虚频抑制 再调制 波分复用无缘光网络 相干接收 060.2330 Fiber optics communications 060.2360 Fiber optics links and subsystems Integrated nano-structured silicon waveguides and devices for high-speed optical communications (Invited Paper)Download:539次
With progress in fabrication technology, integrated photonics plays an increasingly important role in highspeed optical communications, from monolithic transmitters and receivers for advanced optical modulation formats to on-chip subsystems for optical signal processing. We review our recent work on the highly tailorable physical properties of silicon waveguides for communication and signal processing applications, using slot structures. Controllable chromatic dispersion, nonlinearity, and polarization properties of the waveguides are presented, and the enabled wideband wavelength conversion, optical tunable delay, and signal processing of polarization-multiplexing data channels are discussed.
060.4510 Optical communications 130.0130 Integrated optics 130.4310 Nonlinear 130.5440 Polarization-selective devices Semiconductor ring laser (SRL) has been shown to possess robust bistability between its two possible directions, i.e., clockwise (cw) and counter-clockwise (ccw) lasing, routinely demonstrating directional extinction ratio (DER) of > 25 dB. In this paper, experimental schemes and results using the SRL as a universal photonic digital element to form all-optical logic, memory, and signal processing circuits are summarized. It is demonstrated that the SRL can be used for both combinatorial and sequential logic functions, and as all-optical regeneration devices. Furthermore, it is shown that a SRL logic circuit can be all-optically reconfigured to perform different all-optical logic functions.
半导体环形激光器 全光逻辑 全光开关 全光信号处理 130.3750 Optical logic devices 140.3560 Lasers, ring 140.5960 Semiconductor lasers 130.4815 Optical switching devices 130.3120 Integrated optics devices 动态信息
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