共查询到20条相似文献,搜索用时 46 毫秒
1.
Optical performance monitoring using nonlinear detection 总被引:3,自引:0,他引:3
A definitive goal for optical performance monitoring in an optical communications network is to provide comprehensive signal quality information in a cost-effective manner. This paper explores in detail the possibility of using nonlinear optical detection to achieve this goal. Sensitive nonlinear detection techniques commonly used in the field of ultrafast optics are applied to the problem of performance monitoring and are shown to allow quantitative measurements to be made of quantities such as accumulated chromatic dispersion, polarization-mode dispersion impairment, optical signal-to-noise ratio, and extinction ratio. Experiments performed on a 40-Gb/s transmission system demonstrate the immediate viability of this approach for measuring these quantities of interest at practical optical power levels. 相似文献
2.
As optical networks continue to grow towards high capacity and high flexibility, new transmission technologies are being introduced. In order to maintain the quality of signal and control over network in the transparent domains, optical performance monitoring (OPM) systems are becoming a necessity. Phase modulation formats emerge as the solution of choice in transparent domains because of their sensitivity, spectral efficiency, and resilience to optical impairments. In this paper, we demonstrate a flexible OPM method for phase-modulated signals using asynchronous amplitude histogram analysis. We show numerically and experimentally the monitoring of optical signal-to-noise ratio (OSNR), chromatic dispersion (CD), and polarization-mode dispersion (PMD) for differential phase-shift keying (DPSK) and differential quadrature phase-shift keying (DQPSK) signals. The OSNR can be measured within range of 20-35 dB and accumulated chromatic dispersion between 600 and 600 ps/nm. The asynchronous amplitude histogram monitoring method is proved to be a precise and versatile monitoring tool for high-capacity optical networks. 相似文献
3.
Ciaramella E. D'Errico A. Proietti R. Contestabile G. 《Lightwave Technology, Journal of》2006,24(11):4039-4046
The authors demonstrate the potential of using POLarization Shift Keying (POLSK) modulation format combined with semiconductor optical amplifiers (SOAs) in wavelength division multiplexing (WDM) transmission systems. The constant intensity of the POLSK modulation format allows for substantial removal of cross-gain-modulation impairments in SOAs so that practical amplifier spacing values (more than 100 km) are demonstrated in various different experimental configurations. Record WDM transmission experiments at 10 Gb/s by using SOA-based amplification are presented in short and medium reach system architectures using either single mode fiber or nonzero dispersion shifted fiber 相似文献
4.
Experimental Investigation of Delay-Tap Sampling Technique for Online Monitoring of RZ-DQPSK Signals 总被引:1,自引:0,他引:1
《Photonics Technology Letters, IEEE》2009,21(3):179-181
5.
D. Fonseca A.V.T. Cartaxo P. Monteiro 《Photonics Technology Letters, IEEE》2006,18(13):1463-1465
A novel label insertion technique, using an adaptive optical single sideband (OSSB) filter, is experimentally shown. The OSSB filter is used to suppress one of the sidebands of the 40-Gb/s payload signal, and a 2.5-Gb/s intensity modulated signal is inserted as a label in the suppressed sideband. Lower label-payload crosstalk is observed using the OSSB filter compared to the absence of sideband suppression, allowing a reduction of 5 dB in the label power without additional penalty. The enhanced tolerance to group velocity dispersion (GVD) of the payload is experimentally assessed and a 5-dB penalty is observed for 136 ps/nm of accumulated dispersion. Additionally, simulation results show the efficient use of electrical dispersion compensation to improve the GVD tolerance, allowing the doubling of the dispersion tolerance. 相似文献
6.
SHAO Yu-feng CHEN Lin WEN Shuang-chun 《光电子快报》2007,3(2):109-111
A novel transmitter to generate a dark RZ signal with tunable duty cycle and extinction ratio is proposed, by modifying the process of precoding, modulating and coding. A dark RZ signal is generated simply by using one dual-arm Mach-Zehnder LiNbO3 modulator. We demonstrate experimentally that this optical dark RZ signal can be directly measured by a conven- tional binary intensity modulation direct detection (IM-DD) receiver. When different values of duty cycles at 2.5 Gbit/s are adjusted, the experimental results show different BER curves and eye diagrams of the optical dark RZ signal. 相似文献
7.
8.
Kluitmans J.T.M. Kuindersma P.I. Meier M. Mink J. Roll G. Will D.J. 《Electronics letters》1990,26(9):566-567
The transmission experiments demonstrate that operation of 2.488 Gbit/s optical transmission systems over more than 150 km standard SMF is not dispersion limited using today's 1550 nm DFB-lasers. With an extinction ratio as low as 11 dB a dispersion and extinction ratio penalty of less than 0.7 dB was observed.<> 相似文献
9.
Optical generation and distribution of continuously tunable millimeter-wave signals using an optical phase modulator 总被引:5,自引:0,他引:5
Guohua Qi Jianping Yao Seregelyi J. Paquet S. Belisle C. 《Lightwave Technology, Journal of》2005,23(9):2687-2695
In this paper, we propose an approach to generate and distribute two wide bands of continuously tunable millimeter-wave (mm-wave) signals using an optical phase modulator and a fixed optical notch filter. We demonstrate theoretically that the odd-order electrical harmonics are cancelled and even-order electrical harmonics are generated at the output of a photodetector when the optical carrier is filtered out from the phase-modulated optical spectrum. Analysis shows that dispersion compensation is required in order to maintain the suppression of the odd-order electrical harmonics, in order to eliminate signal fading of the generated electrical signal when the optical signal is distributed using conventional single-mode optical fiber. It is experimentally demonstrated that, when the electrical drive signal is tuned from 18.8-25 GHz, two bands of mm-wave signals from 37.6 to 50 GHz and from 75.2 to 100 GHz with high signal quality are generated locally and remotely. This approach does not suffer from the direct current (dc) bias-drifting problem observed when an optical intensity modulator is used. 相似文献
10.
Z.G. Lu F.G. Sun G.Z. Xiao C.P. Grover 《Photonics Technology Letters, IEEE》2004,16(5):1280-1282
We describe and demonstrate a tunable triple-wavelength erbium-doped fiber ring laser along with a method of measuring polarization-mode dispersion (PMD) in optical fibers based on a broad-band orthogonal-pump four-wave mixing in a semiconductor optical amplifier. The measured PMD results for optical fibers are in good agreement with values measured by means of commercial PMD testing equipment. 相似文献
11.
Chromatic dispersions of optical fibers with Kerr-effect nonlinearity are investigated. Under high optical intensity, dispersion characteristics become different from those of the linear state (or weak optical intensity) since the refractive index profile changes in accordance with the intensity profile. Nonlinear dispersion characteristics are calculated for step-index and quadratic profile fibers with core-cladding, core, and cladding nonlinearity. It is shown that although the propagation constant of the step-index fiber increases substantially from the linear value, the group delay and waveguide dispersion do not increase as much 相似文献
12.
Jianjun Yu Lei Xu Yong-Kee Yeo Ji P.N. Ting Wang Gee-Kung Chang 《Photonics Technology Letters, IEEE》2006,18(14):1524-1526
We experimentally demonstrate a novel and simple method to generate a dark return-to-zero (RZ) pulse with tunable pulsewidth and extinction ratio by using a dual-arm LiNbO /sub 3/ intensity modulator. Our experimental results show that this dark RZ pulse signal can be used in a 10-Gb/s optical packet switching system as an optical label. In addition, we demonstrate that this dark RZ label can be easily erased using the gain saturation effect in a semiconductor optical amplifier. 相似文献
13.
McCarthy M.E. Jian Zhao Ellis A.D. Gunning P. 《Lightwave Technology, Journal of》2009,27(23):5327-5335
We experimentally demonstrate the use of full-field electronic dispersion compensation (EDC) to achieve a bit error rate of 5times10- 5 at 22.3 dB optical signal-to-noise ratio for single-channel 10 Gbit/s on-off keyed signal after transmission over 496 km field-installed single-mode fibre with an amplifier spacing of 124 km. This performance is achieved by designing the EDC so as to avoid electronic amplification of the noise content of the signal during full-field reconstruction. We also investigate the tolerance of the system to key signal processing parameters, and numerically demonstrate that single-channel 2160 km single mode fibre transmission without in-line optical dispersion compensation can be achieved using this technique with 80 km amplifier spacing and optimized system parameters. 相似文献
14.
《Photonics Technology Letters, IEEE》2009,21(6):350-352
15.
Wavelength Remodulation Using DPSK Down-and-Upstream With High Extinction Ratio for 10-Gb/s DWDM-Passive Optical Networks 总被引:1,自引:0,他引:1
We propose and demonstrate a novel wavelength remodulation scheme using differential phase-shift keying (DPSK) modulation format in both downstream and upstream signals for ldquocolorlessrdquo dense wavelength-division-multiplexed (DWDM) passive optical networks (PONs). The scheme enables high extinction ratio in both downstream and upstream remodulated signals. Error-free operation was achieved in a 20-km-reach 10-Gb/s DWDM-PON without dispersion compensation. Timing misalignment tolerance between downstream and upstream remodulated signals and maximum launched optical power for the proposed scheme are studied. Comparison with other wavelength remodulation schemes for DWDM-PONs is also performed, showing the proposed scheme can be a potential candidate for next-generation wavelength reuse DWDM-PONs. 相似文献
16.
Khan F. N. Lau A. P. T. Li Z. Lu C. Wai P. K. A. 《Photonics Technology Letters, IEEE》2010,22(3):149-151
17.
Fonseca D. Luis R.S. Cartaxo A.V.T. Monteiro P. 《Photonics Technology Letters, IEEE》2007,19(15):1127-1129
A 10-Gb/s optical single sideband (OSSB) system using alternate mark inversion return-to-zero and ideal electrical precompensation of dispersion is optimized numerically by means of an optical dispersion compensator at the receiver side. The transmission regime observed in the optimized system resembles the pseudolinear regime previously described for systems with bit rates of 40 Gb/s and above. Considering multichannel transmission, the OSSB system has a Q -factor penalty of 2 dB compared to an intensity modulated optical double sideband system with optimized optical dispersion map. 相似文献
18.
《Lightwave Technology, Journal of》2006,24(6):2318-2327
Based on a recently proposed novel optical-signal-modulation technique of adaptively modulated optical orthogonal frequency-division multiplexing (AMOOFDM), numerical simulations of the transmission performance of AMOOFDM signals are undertaken in directly modulated DFB laser (DML)-based single-mode-fiber (SMF) links without optical amplification and dispersion compensation. It is shown that a 30-Gb/s transmission over a 40-km SMF with a loss margin of greater than 4.5 dB is feasible in the aforementioned simple configuration using intensity modulation and direct detection (IMDD). In addition, the DFB-laser frequency chirp and the transmission-link loss are identified to be the key factors limiting the maximum achievable transmission performance of the technique. The first factor is dominant for transmission distances of < 80 km and the second one for transmission distances of > 80 km. It is also observed that fibers of different types demonstrate similar transmission performances, on which fiber nonlinear effects are negligible. 相似文献
19.
Xue-guang YUAN Jin-nan ZHANG Yang-an ZHANG Ming-lun ZHANG Yong-qing HUANG Xiao-min REN 《中国邮电高校学报(英文版)》2009
A novel all-optical label swapping based on optical return zero (RZ) differential quadrature phase shifted keying/inverse return zero amplitude shifted keying (RZ-DQPSK/IRZ-ASK) combined modulation format scheme is investigated and analyzed theoretically. Internet protocol (IP) packets can be efficiently labeled and processed using this proposed scheme. Numerical simulation is taken to demonstrate the transmission characteristic of the all-optical label swapping based on RZ-DQPSK/IRZ-ASK modulation format. The transmission performance can be affected by the duty cycle of the IRZ pulse, the IRZ-ASK label extinction ratio, the dispersion compensation ratio, received optical power and the coupling coefficient of the coupler. Results show that the IRZ-ASK label extinction ratio is almost infinite and preferable performance is obtained. The proposed scheme is a practical solution to meet the data rate and cost-efficient of the optical links simultaneously in tomorrow's all-optical label swapping. 相似文献
20.
Yadlowsky M.J. Deliso E.M. Da Silva V.L. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1997,85(11):1765-1779
The development of optical-fiber amplifiers allowed a dramatic increase in the capacity of optical transmission systems while reducing system costs. Capacity increases are possible because the high output powers afforded by optical-fiber amplifiers support higher bit rates, while their broad bandwidth and slow gain dynamics allow multichannel operation. This benefit comes at the expense of having to manage signal-to-noise ratio degradations due to the accumulation of amplifier noise and dispersion distortions accumulated over the total system link. Furthermore, nonlinear optical effects become significant with the use of high power signals over long lengths of fiber, causing cross talk among the different channels and increasing signal distortions. To fully exploit the potential capacity of wavelength division multiplexing systems, the optical characteristics of the fibers and optical-fiber amplifiers must be optimized. The optical amplifiers should have low noise and flat gain, which can be achieved by using 980-nm pump lasers, optimized fiber glass composition, and gain-flattening filters. The optical fibers should have a small nonzero dispersion and large effective area. Both features can be achieved by optimizing the fiber index profile. This paper summarizes the state of the art in these components and points to directions for future exploration 相似文献