Showing papers on "Polarization mode dispersion published in 1998"
TL;DR: The dispersion properties of photonic crystal fibers are calculated by expression of the modal field as a sum of localized orthogonal functions to derive uniform dispersion values for single mode and double mode fibers.
Abstract: The dispersion properties of photonic crystal fibers are calculated by expression of the modal field as a sum of localized orthogonal functions. Even simple designs of these fibers can yield zero dispersion at wavelengths shorter than 1.27 µm when the fibers are single mode, or a large normal dispersion that is suitable for dispersion compensation at 1.55 µm.
375 citations
20 Sep 1998
TL;DR: In this paper, a novel adaptive optical polarization mode dispersion equalizer was demonstrated in a 10-Gb/s transmission experiment, which comprises a fast electrooptic polarization transformer, an adjustable differential polarization delay line, and a simple electric distortion analyzer for automatic feedback control.
Abstract: We demonstrate a novel, adaptive optical polarization mode dispersion equalizer in a 10-Gb/s transmission experiment. The equalizer comprises a fast electrooptic polarization transformer an adjustable differential polarization delay line, and a simple electric distortion analyzer for automatic feedback control.
190 citations
TL;DR: In this article, the intrinsic and induced birefringence of optical fibers were measured at 1550 nm using the optical frequency-domain reflectometry technique, which confirmed the theoretical analysis, which predicts the appearance of oscillations on the detected Rayleigh backscattering intensity, with periods equal to the polarization beat length.
Abstract: Measurements of intrinsic and induced birefringence of optical fibers are performed at 1550 nm using the optical frequency-domain reflectometry technique. The experiment confirms the theoretical analysis, which predicts the appearance of oscillations on the detected Rayleigh backscattering intensity, with periods equal to the polarization beat length L/sub b/ and to L/sub b//2. Polarization mode-coupling length values are obtained from local birefringence and polarization mode dispersion measurements.
168 citations
TL;DR: In this paper, the effect of the rotation of the principal states of polarization (PSP) is shown to generate power overshoots on the "1" and "0" bit sequences.
Abstract: The time-space varying birefringence in single-mode optical fibers causes the polarization mode dispersion (PMD) to be a serious problem in high bit-rate transmissions. The PMD first- and second-order statistics are well known in the literature, but second-order PMD-induced pulse distortions have still to be clarified for sequences of pulses of arbitrary shape. We give, for the first time, the exact PMD time impulse response, up to second order. We show, both numerically and experimentally, that the effect of the rotation of the principal states of polarization (PSP) is to generate power overshoots on the "1" and "0" bit sequences.
159 citations
Patent•
08 Sep 1998
TL;DR: In this article, the effect of polarization mode dispersion that an optical signal experiences as it propagates through an optical transmission fiber is compensated for at a receiver using a birefringent compensator, in which the compensator automatically and adaptively generates a level of differential time delay that substantially equals the optical signal experience, but of different sign, and, therefore, essentially cancels out the undesired delay.
Abstract: The effect of polarization mode dispersion that an optical signal experiences as it propagates through an optical transmission fiber is compensated for at a receiver using a birefringent compensator, in which the compensator automatically and adaptively generates a level of differential time delay that substantially equals the differential time delay that the optical signal experiences, but of different sign, and, therefore, essentially cancels out the undesired delay.
154 citations
TL;DR: A simple and exact analytical expression is derived for the amount of broadening that a pulse suffers when it is subjected to the combined actions of polarization mode dispersion, chromatic disp immersion, and chirping.
Abstract: A simple and exact analytical expression is derived for the amount of broadening that a pulse suffers when it is subjected to the combined actions of polarization mode dispersion, chromatic dispersion, and chirping. The theory is then applied to various manifestations of second-order polarization mode dispersions.
130 citations
TL;DR: In this paper, the authors present a description of the phenomenon and of its effects on analog and digital signals, propose definitions, discuss some orders of magnitudes and to present some numerical simulations and experimental results.
Abstract: Second-order polarization mode dispersion (PMD) is a major limitation to the transmission capabilities of analog systems and of high bit rate digital systems. Basically, the effect of second-order PMD is the same as that of chromatic dispersion. However, like all polarization effects in standard single-mode fibers, the effects of second-order PMD are stochastic, due to the random polarization mode coupling that occurs in such fibers. Hence, the effects of second-order PMD fluctuate with time. The purpose of this article is to present a description of the phenomenon and of its effects on analog and digital signals, to propose definitions, to discuss some orders of magnitudes and to present some numerical simulations and experimental results. Some general understanding of the phenomena of first-order PMD are assumed.
119 citations
TL;DR: In this paper, the impact of the spectral signal width on PMD-induced system outage probability was studied for the first time, and it was shown that low bandwidth modulation schemes (external modulator, low chirp laser) do not suffer from additional outage degradation due to second-order PMD.
Abstract: A theoretical approach is proposed that allows one to quantify the impact of fiber polarization mode dispersion (PMD) on optical binary transmission taking into account not only first-order polarization mode dispersion, but also signal distortion induced by second-order PMD. Using this approach the impact of the spectral signal width on PMD-induced system outage probability could be studied for the first time. An analysis of 10-Gb/s transmission exhibits that, as long as the mean PMD remains below the commonly accepted limit (about 10 ps) for negligible outage, a linear chirp of up to 30 GHz does not lead to an additional increase of the system outage. This result confirms that low bandwidth modulation schemes (external modulator, low chirp laser) do not suffer from additional outage degradation due to second-order PMD.
118 citations
TL;DR: Using coupled-mode theory, a theoretical model shows that PMD can be reduced effectively by use of frequency-modulated spin profiles.
Abstract: Using coupled-mode theory, we develop a theoretical model to analyze the effects of fiber spin profiles on polarization mode dispersion (PMD). Constant, sinusoidal, and frequency-modulated spin profiles are examined, and phase-matching conditions are analyzed. Our analysis shows that PMD can be reduced effectively by use of frequency-modulated spin profiles.
105 citations
TL;DR: In this paper, the authors presented a completely new method able to characterize polarization mode dispersion (PMD) properties of randomly birefringent single-mode fibers, using polarization sensitive backscattering technique.
Abstract: This paper presents a completely new method able to characterize polarization mode dispersion (PMD) properties of randomly birefringent single-mode fibers, using polarization sensitive backscattering technique. We show analytical relationships between evolution of polarization state of backscattered signal with respect to state of polarization of forward one. Our technique allows one to measure differential group delay, beat length, and correlation length at the same time over long single-mode fibers using only one fiber end. Experimental data fit very well with numerical results, confirming the capability of our technique for fast routine characterization of PMD during cabling, before and after installation.
93 citations
TL;DR: In this paper, it was shown that for very strong dispersion management, the energy enhancement depends not only on the dispersion map strength, but also on the ratio between the difference in dispersion difference and the average dispersion, which can be exploited to almost equalise the energy per channel.
Abstract: It is shown that for very strong dispersion management, the energy enhancement depends not only on the dispersion map strength, but also on the ratio between the dispersion difference and the average dispersion. In WDM systems operating near zero average dispersion, this dependence can be exploited to almost equalise the energy per channel.
TL;DR: Analytic and numerical evidence is presented that demonstrates that a dispersion-managed breather can be supported in an optical fiber even when the average dispersion is in the normal regime.
Abstract: Analytic and numerical evidence is presented that demonstrates that a dispersion-managed breather can be supported in an optical fiber even when the average dispersion is in the normal regime. This nonlinear behavior, which is contrary to guiding-center theory, is shown to originate from the reversible dynamics associated with the strong quadratic chirp that is generated in both the anomalous and the normal dispersion regimes.
Patent•
08 May 1998
TL;DR: In this article, the authors proposed a method and apparatus for optimizing dispersion in an optical fiber transmission line. But the method is limited to the case where the optical signal is modulated by a data signal having a bit rate of B bits/second and the specific frequency component is a B hertz component of optical signal.
Abstract: A method and apparatus for optimizing dispersion in an optical fiber transmission line. The method and apparatus (a) determine an optimum amount of total dispersion of an optical transmission line corresponding to a power level of an optical signal transmitted through the optical transmission line; (b) control dispersion of the optical transmission line so that the total dispersion up to a specific point along the optical transmission line becomes approximately zero; and (c) add dispersion to the optical transmission line downstream of the specific point, to obtain the determined optimum amount of total dispersion. The control of dispersion in (b), above, can be performed in several different manners. For example, the control of dispersion can include (i) detecting the intensity of a specific frequency component of the optical signal, the optical signal having an intensity v. total dispersion characteristic curve with at least two peaks; and (ii) controlling the amount of total dispersion of the transmission line to substantially minimize the intensity of the specific frequency component between the two highest peaks of the intensity v. total dispersion characteristic curve of the optical signal. Assuming that the optical signal is modulated by a data signal having a bit rate of B bits/second, then the specific frequency component is preferably a B hertz component of the optical signal.
Patent•
10 Feb 1998TL;DR: In this article, a fixed and variable dispersion compensator can be located at different positions in an optical transmission line, such that one may be in a transmitter and the other in a receiver.
Abstract: An apparatus which compensates for dispersion in an optical transmission line. The apparatus includes a fixed dispersion compensator and a variable dispersion compensator. The fixed dispersion compensator has a fixed dispersion amount and coarsely compensates for the dispersion in the transmission line. The variable dispersion compensator has a variable dispersion amount and finely compensates for the dispersion in the transmission line. The fixed and variable dispersion compensators can be located at many positions. For example, one may be in a transmitter and the other may be in a receiver. Both may be in the transmitter and/or the receiver. One may be in either the transmitter or the receiver, with the other in an optical repeater positioned along the transmission line.
TL;DR: In this paper, the authors analyzed the mutual interaction between a pair of stretched pulses propagating in periodically amplified dispersion-managed fibers by means of the variational method and showed that the location of the amplifier within a unit cell of the dispersion management significantly affects the energy enhancement and interaction between adjacent pulses.
Abstract: Mutual interaction between a pair of stretched pulses propagating in periodically amplified dispersion-managed fibers is analyzed by means of the variational method. It is shown that the location of the amplifier within a unit cell of the dispersion management significantly affects the energy enhancement and interaction between adjacent pulses. The collapse distance of the two pulses can be extended by suitably positioning the amplifier.
TL;DR: In this article, the first fully polarization sensitive optical time domain reflectometer (POTDR) is implemented, which enables the determination of both the linear and twist induced circular birefringence distribution along the fiber.
Abstract: We report the implementation of the first fully polarization sensitive optical time domain reflectometer (POTDR). This nondestructive measurement technique, requiring access to one fiber end only, enables the determination of both the linear and twist induced circular birefringence distribution along the fiber. This information, combined with a knowledge of the mode coupling length, enables the evaluation of the polarization mode dispersion (PMD) properties of fibers and optical cables exhibiting both types of birefringence, as well as identifying fiber sections with and without twist. The POTDR, which has a spatial resolution of 0.3 m, could also be used for monitoring the birefringence properties of fibers at the manufacturing stage, leading to optimization of fabrication techniques to minimize PMD.
TL;DR: In this article, the initial linear birefringence determines the necessary spinning parameters to produce spun fiber with optimum differential group delay (DGD) and polarization mode dispersion (PMD) properties.
Abstract: This paper shows how the initial linear birefringence determines the necessary spinning parameters to produce spun fiber with optimum differential group delay (DGD) and polarization mode dispersion (PMD) properties. DGD measurements are reported on two pairs of fibers, each pair having been fabricated from a particular fiber preform. The fiber pairs each consist of a sample of spun and unspun fiber. These measurements are then compared with theoretical simulations for each fiber to determine the required range of spinning parameters for a given initial linear birefringence. These results should help in optimizing the spinning parameters for producing high-performance spun fibers.
TL;DR: It is shown that there is a trade-off between these two properties and, generally, larger effective areas are associated with larger mode-field diameters.
Abstract: A class of low-nonlinearity dispersion-shifted fibers based on depressed-core multistep index profiles is investigated. A systematic approach for designing these fibers in which a reference W-index profile is used to initiate the design is presented. Transmission properties, including effective area, mode-field diameter, dispersion, dispersion slope, and cutoff wavelength, are evaluated for several design examples. The effects of varying fiber dimensions and indices on effective area and mode-field diameter are assessed. It is shown that there is a trade-off between these two properties and, generally, larger effective areas are associated with larger mode-field diameters. Dispersion-shifted single-mode fiber designs with effective areas of from 78 to 210 microm2 and the corresponding mode-field diameter of from 8.94 to 14.94 microm, dispersion less than 0.07 ps/nm km, and dispersion slope of approximately 0.05 ps/nm2 km are presented.
TL;DR: In this paper, the statistics of the global polarization dependent loss resulting from the concatenation of several components with PDL, connected by standard optical fibers or by elements having some polarization mode dispersion (PMD), are discussed.
Abstract: Due to the statistical nature of the evolution of the polarization state in optical fibers and components, it is difficult to measure the global polarization dependent loss (PDL) of a series of concatenated components, each having a different PDL value. The global PDL of concatenated components with PDL cannot be obtained by a simple addition of the single PDL values, moreover, it requires a statistical description. In the present work the statistics of the PDL resulting from the concatenation of several components with PDL, connected by standard optical fibers or by elements having some polarization mode dispersion (PMD) is discussed. Simulations and experimental results supporting the existing theory are presented.
22 Feb 1998
TL;DR: In this paper, the authors evaluated the PMD sensitivity in 40-Gbit/s OTDM transmission using a PMD emulator and found that the 40-GHz frequency component in the baseband signal is sensitive to waveform distortion due to PMD, and can be used for PMD monitoring.
Abstract: Summary form only given. We established guidelines for the 40-Gbit/s system design with optimum dispersion compensation and optical power against chromatic dispersion and self-phase modulation (SPM). The signal distortion due to PMD remains a major limitation on transmission distance. This paper describes our experimental evaluation of PMD sensitivity in 40-Gbit/s OTDM transmission using a PMD emulator. We also found that the 40-GHz frequency component in the baseband signal is sensitive to waveform distortion due to PMD, and can be used for PMD monitoring. We also investigated PMD sensitivity and monitoring in 10-Gbit/s nonreturn to zero (NRZ) transmission experiments.
TL;DR: This work demonstrates the possibility of transmitting solitonlike pulses over 2000 km of standard fiber at a single-channel data rate of 40 Gbits/s, and employs a novel dispersion map to overcome the large fiber dispersion.
Abstract: We demonstrate, through numerical simulations, the possibility of transmitting solitonlike pulses over 2000 km of standard fiber at a single-channel data rate of 40 Gbits/s. The system used here employs a novel dispersion map to overcome the large fiber dispersion. The longest transmission distance was achieved with pulses that did not exhibit the enhanced energy normally associated with dispersion management and indeed had lower energy than an equivalent average soliton.
TL;DR: In this article, a fiber-based quasi-soliton-like pulse is proposed to propagate quasi-solons, which allows significantly improved transmission property by reducing much of the intrinsic problems of solitons.
TL;DR: In this paper, the authors measured the time evolution of polarization mode dispersion (PMD) for installed aerial and buried cables and for a spooled fiber in a temperature controlled chamber.
Abstract: The fluctuation of polarization mode dispersion (PMD) due to environmental change is an important issue for fiber-optic communication systems. We measure the time evolution of PMD for installed aerial and buried cables and for a spooled fiber in a temperature controlled chamber. The results show that PMD fluctuates much more rapidly for aerial cables than for buried cables. The magnitude of PMD is different for the three fibers and our results also show that the magnitude of PMD fluctuation depends on the magnitude of the PMD.
Patent•
02 Jul 1998TL;DR: In this article, the authors proposed an apparatus for compensating for dispersion of an optical fiber in an optical line, which compensates for the dispersion generated in the optical fiber when an optical signal produced by an optical transmitter is transmitted to an optical receiver via the optical line.
Abstract: An apparatus for compensating for dispersion of an optical fiber in an optical line, which compensates for dispersion generated in the optical fiber when an optical signal produced by an optical transmitter is transmitted to an optical receiver via the optical line, is provided. The apparatus includes a dispersion compensation fiber for compensating an optical signal produced by an optical transmitter in order to predict and compensate for dispersion generated in the optical line, a dispersion compensation filter for controlling the dispersion value of the optical signal dispersion-compensated by the dispersion compensation fiber, to gain zero overall dispersion, and an optical amplifier for amplifying a signal having a dispersion value adjusted by the dispersion compensation filter and outputting the result to the optical line. Accordingly, it is easy to zero a dispersion value of an optical fiber in the optical line by regulation of the dispersion compensation fiber and filter. When the dispersion value varies with the deterioration of the optical fiber in the optical line, continuous compensation is not possible using only the dispersion compensation fiber. However, continuous compensation is easily made by adding the dispersion compensation filter.
20 Sep 1998
22 Feb 1998
TL;DR: In this paper, the authors present a method to make the nonlinear optical loop mirror (NOLM) fully insensitive to polarization changes in any of the two input signals by having a fiber with random birefringence.
Abstract: Summary form only given. Polarization independence is a critical issue for all-optical logic gates if they are to be implemented in future high-speed data transmission networks. Here we present a method to make the nonlinear optical loop mirror (NOLM) fully insensitive to polarization changes in any of the two input signals by having a fiber with random birefringence, i.e., a fiber with moderate polarization-mode dispersion (PMD). The basic idea is to make the wavelength difference between the signal and control pulses large enough so the polarization states, when evolving through the fiber, will be different for the two signals as a result of PMD in the fibre.
TL;DR: In this paper, the use of apodized Bragg fiber gratings for dispersion compensation, when operated in transmission, is discussed, and it is shown that these devices have several intrinsic limitations.
Abstract: The use of apodized Bragg fiber gratings for dispersion compensation, when operated in transmission, is discussed. Using a system simulation, it is shown that these devices have several intrinsic limitations. If these limitations can be overcome, apodized Bragg fiber gratings can be used to compensate a 10-Gb/s system over 200 km of standard fiber with an eye-closure penalty of less than 2 dB.
Patent•
29 Jul 1998
TL;DR: In this paper, a method and an optical transmission system for compensation of dispersion in optical transmission lines in which dispersion compensation fibers are applied, with the dispersion compensated fibers being arranged at the beginning as well as at the end of the line segments of the optical fibers forming the transmission line.
Abstract: The invention relates to a method and an optical transmission system for compensation of dispersion in optical transmission lines in which dispersion compensation fibers are applied, with the dispersion compensation fibers being arranged at the beginning as well as at the end of the line segments of the optical fibers forming the transmission line. The signal distortions due to non-linear effects are reduced by making use of the recognition that non-linearities should only occur at as small as possible an accumulated dispersion. This is obtained by an unequal division of the dispersion compensation fiber applied for the compensation of the dispersion of the optical fiber, with the part of the dispersion compensation fiber attached at the beginning of a line segment being directly connected to the optical fiber and having an accumulated dispersion which is smaller as to amount than the accumulated dispersion of the part of the dispersion compensation fiber attached at the end of the optical fiber.
22 Feb 1998
TL;DR: This paper explains why second-order PMD may not significantly reduce the maximum tolerable PMD if only first-order was considered, and shows the statistics of second- order PMD.
Abstract: Summary form only given. Increasing the bit rate to 10 Gbit/s and beyond in a single channel for the terrestrial optical links is one of today's major challenges. At 10 Gbit/s, both first- and second-order polarization-mode dispersion (PMD) are important impairments, which have been already studied theoretically and experimentally. It has already been shown that the impact of second-order PMD is magnified by chromatic dispersion. However, the statistical point of view was not analyzed. In this paper, we will first show the statistics of second-order PMD, and we will explain why second-order PMD may not significantly reduce the maximum tolerable PMD if only first-order was considered.
Patent•
27 Nov 1998TL;DR: In this paper, a dispersion compensation control device used in an ultra-high-speed optical communication system using optical time division multiplexing comprises a first specific frequency component detector (2a), a first intensity detector (3a), and a polarization mode dispersion controller (220a).
Abstract: A dispersion compensation control device used in an ultrahigh-speed optical communication system using optical time division multiplexing comprises a first specific frequency component detector (2a) for detecting a first specific frequency component in a baseband spectrum of a tranmitted light signal inputted into the receiving side via a transmission fiber serving as a transmission line (6a), a first intensity detector (3a) for acquiring information on the intensity of the detected first specific frequency component detected, and a polarization mode dispersion controller (220a) for controlling the polarization mode dispersion of the transmission line (6a) so that the acquired intensity of the first specific frequency component may be maximum. Thus, the polarization mode dispersion that has occurred in a high-speed light signal can readily be detected and compensated for.