Showing papers on "Polarization mode dispersion published in 2006"
05 Jun 2006
TL;DR: This paper discusses the generation and detection of multigigabit/s intensity- and phase-modulated formats, and highlights their resilience to key impairments found in optical networking, such as optical amplifier noise, multipath interference, chromatic dispersion, polarization-mode dispersion.
Abstract: Fiber-optic communication systems form the high-capacity transport infrastructure that enables global broadband data services and advanced Internet applications. The desire for higher per-fiber transport capacities and, at the same time, the drive for lower costs per end-to-end transmitted information bit has led to optically routed networks with high spectral efficiencies. Among other enabling technologies, advanced optical modulation formats have become key to the design of modern wavelength division multiplexed (WDM) fiber systems. In this paper, we review optical modulation formats in the broader context of optically routed WDM networks. We discuss the generation and detection of multigigabit/s intensity- and phase-modulated formats, and highlight their resilience to key impairments found in optical networking, such as optical amplifier noise, multipath interference, chromatic dispersion, polarization-mode dispersion, WDM crosstalk, concatenated optical filtering, and fiber nonlinearity
772 citations
TL;DR: The generation and detection of multigigabit/second intensity- and phase-modulated formats are reviewed to highlight their resilience to key impairments found in optical networking, such as optical amplifier noise, chromatic dispersion, polarization-mode dispersion.
Abstract: Advanced optical modulation formats have become a key ingredient to the design of modern wavelength-division-multiplexed (WDM) optically routed networks. In this paper, we review the generation and detection of multigigabit/second intensity- and phase-modulated formats and highlight their resilience to key impairments found in optical networking, such as optical amplifier noise, chromatic dispersion, polarization-mode dispersion, WDM crosstalk, concatenated optical filtering, and fiber nonlinearity
490 citations
TL;DR: Recent progress in forward error correction (FEC) for optical communications is reviewed and the error count function has proved useful for the adaptive equalization of both chromatic dispersion and PMD.
Abstract: Recent progress in forward error correction (FEC) for optical communications is reviewed. The various types of FEC are classified as belonging to one of three generations. A third-generation FEC, based on a block turbo code, has been fully integrated in very large scale integration, and thanks to the use of 3-bit soft decision, a net coding gain of 10.1 dB was demonstrated experimentally. That has brought a number of positive impacts to existing systems. The Shannon limit is discussed for hard and soft decision decoding. The interplay between FEC and error bursts is discussed. Fast polarization scrambling with FEC has been effective in mitigating polarization mode dispersion (PMD). The error count function has proved useful for the adaptive equalization of both chromatic dispersion and PMD
197 citations
TL;DR: In this paper, the dispersion of ultrafast pulses in a photonic crystal waveguide as a function of optical frequency was studied in both experiment and theory, and the effect of dispersion on the shape of the pulses was determined.
Abstract: We have studied the dispersion of ultrafast pulses in a photonic crystal waveguide as a function of optical frequency, in both experiment and theory. With phase-sensitive and time-resolved near-field microscopy, the light was probed inside the waveguide in a non-invasive manner. The effect of dispersion on the shape of the pulses was determined. As the optical frequency decreased, the group velocity decreased. Simultaneously, the measured pulses were broadened during propagation, due to an increase in group velocity dispersion. On top of that, the pulses exhibited a strong asymmetric distortion as the propagation distance increased. The asymmetry increased as the group velocity decreased. The asymmetry of the pulses is caused by a strong increase of higher-order dispersion. As the group velocity was reduced to 0.116(9)·c, we found group velocity dispersion of -1.1(3)·106 ps2/km and third order dispersion of up to 1.1(4)·105 ps3/km. We have modelled our interferometric measurements and included the full dispersion of the photonic crystal waveguide. Our mathematical model and the experimental findings showed a good correspondence. Our findings show that if the most commonly used slow light regime in photonic crystals is to be exploited, great care has to be taken about higher-order dispersion.
153 citations
TL;DR: In this paper, the Manakov-PMD equation was derived using multiple-length-scale techniques and it was shown that the scalar nonlinear Schro/spl uml/dinger equation is valid when the signal is initially in a single polarization state.
Abstract: Aspects of the interaction of the Kerr nonlinearity and polarization mode dispersion (PMD) are reviewed. The basic equation that governs this interaction on the length scale of interest in optical fiber communications systems is the Manakov-PMD equation. This equation is derived using multiple-length-scale techniques. The focus of the derivation is the elucidation of common misunderstandings and pitfalls rather than mathematical rigor. It is shown that the scalar nonlinear Schro/spl uml/dinger equation is valid when PMD is absent and the signal is initially in a single polarization state. Two examples are then presented that illustrate the complexity of the interaction between nonlinearity and PMD. The first example considers the interaction of a nonlinearly induced chirp with PMD. As the power increases, one can obtain an improved eye opening relative to the case when PMD is absent. The second example considers the effect of nonlinear polarization rotation in a wavelength-division-multiplexed system. When nonlinear polarization rotation is important, the principal states of polarization become time dependent and PMD compensation becomes ineffective. This problem can be mitigated through the use of line codes.
138 citations
TL;DR: A novel algorithm to overcome the issues related to the practical availability of finite-range birefringent components and to solve the requirement for endless stabilization is presented.
Abstract: The control of the state of polarization (SOP) of light remains one of the open issues in optical communications. In particular, the achievement of a stabilization of the SOP can find many applications in advanced optical communication systems: from the mitigation of polarization-mode dispersion to the development of novel multilevel modulation formats. In this paper, theoretical and experimental aspects of polarization stabilization are dealt with, and a novel algorithm to overcome the issues related to the practical availability of finite-range birefringent components and to solve the requirement for endless stabilization is also presented. A complete analysis of the control algorithm, based on the Jones matrix formalism, is also presented. The practical implementation of the polarization stabilizer is discussed, and experimental demonstrations based on liquid crystal and magnetooptical retarders are shown
122 citations
TL;DR: In this article, the performance of the polarization-nulling technique was analyzed and several techniques to overcome the effect of nonlinear birefringence in a highly nonlinear transmission link.
Abstract: The polarization-nulling technique utilizes the different properties of optical signal and amplified spontaneous emission (ASE) noise for accurate monitoring of the optical-signal-to-noise ratio (OSNR) in dynamic optical networks. However, the performance of this technique is bound to be deteriorated if the signal is depolarized by polarization-mode dispersion and/or nonlinear birefringence or the ASE noise is partially polarized due to polarization-dependent loss (PDL) in the transmission link. The authors analyze these effects on the performance of the polarization-nulling technique and introduce several techniques to overcome these problems. These improved versions of the polarization-nulling techniques could monitor the OSNR with accuracy of better than plusmn1 dB, even when the differential group delay is as large as 60 ps. These techniques could also negate the effect of the signal depolarization caused by nonlinear birefringence in a highly nonlinear transmission link. The effect of the partially polarized ASE noise due to PDL is found to be not severe in most cases, as long as the PDL/span is smaller than 0.2 dB. To verify the possibility of using the polarization-nulling technique in real systems, the OSNR of the wavelength-division-multiplexed (WDM) signals transmitted through a 120-km-long aerial fiber link is measured for one week. No significant degradation in the monitoring accuracy is observed during this long-term measurement. In addition, the performance of the polarization-nulling technique in an ultralong-haul transmission link is evaluated by using a 640-km-long recirculating loop. The results show that this technique could accurately measure the OSNR in the transmission link longer than 3200 km. From these results, the authors conclude that the polarization-nulling technique is well suited for monitoring the OSNR in dynamic WDM networks
109 citations
TL;DR: Dual-concentric-core photonic crystal fibers having larger negative dispersion coefficient as well as compensating for dispersion slope of SMFs in the entire C band with large effective area can be designed.
Abstract: Chromatic dispersion profile of dual-concentric-core photonic crystal fibers is optimized for broadband dispersion compensation of single mode fibers (SMFs) by using genetic algorithm incorporated with full-vector finite-element method. From the numerical results presented here, it is found that by increasing the distance between central core and outer ring core, larger negative dispersion coefficient and better dispersion slope compensation are possible. There is a tradeoff between the magnitude of negative dispersion coefficient and dispersion slope compensation due to the concave dispersion profile of dual-concentric-core photonic crystal fibers. In spite of the tradeoff, dual-concentric-core photonic crystal fibers having larger negative dispersion coefficient as well as compensating for dispersion slope of SMFs in the entire C band with large effective area can be designed.
100 citations
TL;DR: The authors discuss the proposition that most of the temporal PMD changes that are observed in installed routes arise primarily from a relatively small number of "hot spots" along the route that are exposed to the ambient environment, whereas the buried shielded sections remain largely stable for month-long time periods.
Abstract: Polarization mode dispersion (PMD), a potentially limiting impairment in high-speed long-distance fiber-optic communication systems, refers to the distortion of propagating optical pulses due to random birefringences in an optical system. Because these perturbations (which can be introduced through manufacturing imperfections, cabling stresses, installation procedures, and environmental sensitivities of fiber and other in-line components) are unknowable and continually changing, PMD is unique among optical impairments. This makes PMD both a fascinating research subject and potentially one of the most challenging technical obstacles for future optoelectronic transmission. Mitigation and compensation techniques, proper emulation, and accurate prediction of PMD-induced outage probabilities critically depend on the understanding and modeling of the statistics of PMD in installed links. Using extensive data on buried fibers used in long-haul high-speed links, the authors discuss the proposition that most of the temporal PMD changes that are observed in installed routes arise primarily from a relatively small number of "hot spots" along the route that are exposed to the ambient environment, whereas the buried shielded sections remain largely stable for month-long time periods. It follows that the temporal variations of the differential group delay for any given channel constitute a distinct statistical distribution with its own channel-specific mean value. The impact of these observations on outage statistics is analyzed, and the implications for future optoelectronic fiber-based transmission are discussed
94 citations
TL;DR: This paper thoroughly investigates the maximum-likelihood sequence detection (MLSD) receiver for the optical ON-OFF keying (OOK) channel in the presence of both polarization mode dispersion and group velocity dispersion.
Abstract: This paper thoroughly investigates the maximum-likelihood sequence detection (MLSD) receiver for the optical ON-OFF keying (OOK) channel in the presence of both polarization mode dispersion and group velocity dispersion (GVD). A reliable method is provided for computing the relevant performance for any possible value of the system parameters, with no constraint on the sampling rate. With one sample per bit time, a practically exact expression of the statistics of the received samples is found, and therefore the performance of a synchronous MLSD receiver is evaluated and compared with that of other electronic techniques such as combined feedforward and decision-feedback equalizers (FFE and DFE). It is also shown that the ultimate performance of electronic processing can be obtained by sampling the received signal at twice the bit rate. An approximate accurate closed-form expression of the receiver metrics is also identified, allowing for the implementation of a practically optimal MLSD receiver
86 citations
01 Dec 2006
TL;DR: In this paper, the authors demonstrate transmission and demodulation of 40Gbit/s per wavelength data, using 10Gbaud polarisation multiplexed QPSK, including carrier recovery and equalisation of all linear impairments, including chromatic dispersion and polarisation mode dispersion.
Abstract: We demonstrate transmission and demodulation of 40Gbit/s per wavelength data, using 10Gbaud polarisation multiplexed QPSK. The digital coherent receiver includes carrier recovery and equalisation of all linear impairments, including chromatic dispersion and polarisation mode dispersion.
TL;DR: In this paper, the authors proposed a coherent optical orthogonal frequency division multiplexing (CO-OFDM) to mitigate polarisation mode dispersion (PMD) in optical media.
Abstract: Coherent optical orthogonal frequency division multiplexing (CO-OFDM) to mitigate polarisation mode dispersion (PMD) in optical media is proposed. It is shown that PMD in deployed links can be overcome by CO-OFDM systems at 10 Gbit/s and beyond.
TL;DR: In this paper, the polarization properties of randomly birefringent strongly-spun fibers are analyzed by means of a simplified model, which applies to a wide range of spin profiles that are either deterministic or random.
Abstract: Spun fibers are one of the most viable solutions to polarization mode dispersion. In this paper, their polarization properties are reviewed with special emphasis on randomly birefringent strongly spun fibers. The analysis is carried out by means of a new simplified model, which applies to a wide range of spin profiles that are either deterministic or random. It is shown that in general, a strongly spun fiber is characterized by an apparent random linear birefringence and an apparent deterministic circular birefringence. The latter term may originate unusual polarization properties; yet, in some cases of practical interest, it is equal to zero, and when this happens, the strongly spun fiber has the same statistical properties of an unspun one
TL;DR: In this article, the performance of symbol-by-symbol maximum a posteriori (sbs-MAP) soft-in/soft-out (SISO) decoders is investigated to mitigate the effects of a polarization-mode dispersion (PMD) in nonreturn-to-zero (NRZ) intensity-modulated optical-fiber transmission systems.
Abstract: This paper investigates the performance of iterative (turbo) equalization to mitigate the effects of a polarization-mode dispersion (PMD) in nonreturn-to-zero (NRZ) intensity-modulated optical-fiber transmission systems. A PMD can lead to severe distortions in the received electrical signal and is a key limiter for the development of high-bit-rate transmission over currently used fibers. In order to reduce the distortions due to a PMD, the performance of symbol-by-symbol maximum a posteriori (sbs-MAP) soft-in/soft-out (SISO) decoders is studied. The SISO algorithms are adapted to the noise statistics of the optical channel where the photo detector leads to a non-Gaussian signal-dependent noise at the receiver side. The modified SISO algorithms are successfully employed for turbo equalization and results show that iterative (turbo) equalization and decoding for the compensation of a PMD can lead to a tremendous reduction in the bit error ratio (BER). Moreover, it is shown that, due to the robustness of mutual information, the extrinsic information transfer (EXIT) chart can be applied for the design of iterative receivers in optical transmission systems even with a non-Gaussian noise
TL;DR: In this paper, the effects of chromatic dispersion, polarization-mode dispersion (PMD), and polarization-dependent loss (PDL) on the intensity noise suppression of spectrum-sliced incoherent light sources achieved by using gain-saturated (GS) optical amplifiers (SOAs) are investigated.
Abstract: The effects of chromatic dispersion (CD), polarization-mode dispersion (PMD), and polarization-dependent loss (PDL) on the intensity noise suppression of spectrum-sliced incoherent light sources achieved by using gain-saturated (GS) semiconductor optical amplifiers (SOAs) are investigated. Passing the spectrum-sliced incoherent light through SOAs, the excess intensity noise (EIN) originating from beating of spontaneous emission against itself can be greatly reduced. However, since the noise suppression is achieved by an elaborate balancing between numerous frequency/polarization components of light, thus, forming a high correlation between them, it is vulnerable to frequency/polarization-dependent optical phenomena. Through Q-factor and bit error rate (BER) measurements, this paper shows that CD, PMD, or PDL deteriorates the SOA-based noise suppression technique by breaking the correlation. Spectral analysis is also performed to investigate the frequency dependency of these effects. It is shown that CD and PMD negate the noise suppression giving rise to intensity noise from high frequencies, whereas there is no frequency dependence for PDL effects. Therefore, CD-, PMD-, or PDL-induced penalties for incoherent light sources using the SOA-based noise suppression technique are considerably greater than those produced by pulse broadening or distortion alone.
TL;DR: In this paper, the authors review and compare various techniques for PMD emulation and compensation, with an emphasis on the application of programmable differential-group-delay (DGD) elements for manipulating PMD effects.
Abstract: Polarization-mode dispersion (PMD) still remains a challenge for high-data-rate optical-communication systems. Practical solutions are desirable for PMD emulation, monitoring, and compensation. The authors review and compare various techniques for PMD emulation and compensation, with an emphasis on the application of programmable differential-group-delay (DGD) elements for manipulating PMD effects. The authors pay special attention to advanced emulation techniques, such as importance sampling and the hinge model, for practical applications. The tunability of programmable DGD elements proves to be attractive for both system performance evaluation and overall optimization
TL;DR: An optimized design of a dispersion compensating photonic crystal fiber (PCF) to achieve gain-flattened Raman performances over S-band using a single pump and remains single mode over the range of operating wavelengths is presented.
Abstract: This paper presents an optimized design of a dispersion compensating photonic crystal fiber (PCF) to achieve gain-flattened Raman performances over S-band using a single pump. Genetic algorithm interfaced with an efficient full-vectorial finite element modal solver based on curvilinear edge/nodal elements is used as an optimization tool for an accurate determination of PCF design parameters. The designed PCF shows high negative dispersion coefficient (−264 ps/nm/km to -1410 ps/nm/km) and negative dispersion slope, providing coarse dispersion compensation over the entire S-band. The module comprised of 1.45-km long optimized PCF exhibits ±0.46 dB gain ripples over 50 nm wide bandwidth and shows a very low double Rayleigh backscattering value (-59.8 dB). The proposed module can compensate for the dispersion accumulated in one span (80-km) of standard single mode fiber with a residual dispersion of ±700 ps/nm, ensuring its applicability for 10 Gb/s WDM networks. Additionally, the designed PCF remains single mode over the range of operating wavelengths.
TL;DR: In this paper, the authors demonstrate in-service channel monitoring of a chromatic dispersion and polarization-mode dispersion (PMD) for a return-to-zero differential phase-shift keying (RZ-DPSK) signals based on the asynchronous amplitude-histogram evaluation (AAHE) technique.
Abstract: The authors demonstrate in-service channel monitoring of a chromatic dispersion (CD) and polarization-mode dispersion (PMD) for a return-to-zero differential phase-shift keying (RZ-DPSK) signals based on the asynchronous amplitude-histogram evaluation (AAHE) technique. The waveform evolution of the RZ-DPSK signal under the effects of the CD and PMD is investigated analytically and numerically. The CD leads to a power level splitting at the valley of the waveform before demodulation. The intensities of these two levels further increase due to the PMD. By tracking the intensities of these levels using the AAHE method, the CD and PMD can be measured. The principle of a simultaneous monitoring of the CD and PMD is demonstrated experimentally for 10-Gb/s RZ-DPSK signals. The effects of the signal's optical signal-to-noise ratio and the number of the sampling points on the accuracy of the monitoring results are also presented.
TL;DR: In this paper, a distortion-free optical transmission method that can eliminate any kind of linear perturbation including jitter, polarization-mode dispersion, and higher order dispersion as well as time-varying dispersion was proposed.
Abstract: This paper describes a new distortion-free optical transmission method that can eliminate any kind of linear perturbation including jitter, polarization-mode dispersion, and higher order dispersion as well as time-varying dispersion. This method uses transform-limited pulses and time-domain optical Fourier transformation (OFT). With this technique, particular attention is given to the spectral envelope profile of the transmitted signal, which is unchanged regardless of the type and magnitude of the linear perturbation in the transmission fiber. OFT converts the unchanged spectral profile into the time domain and allows to obtain undistorted original waveforms at the output. Experimental and analytical results to show the effectiveness of this method are presented, especially when the method is applied to high-speed signals up to 160 Gb/s, which are sensitive to both higher order and time-varying dispersions. This paper also describes a new all-optical time-domain Fourier transformation technique that uses an optical parabolic pulse. This technique is promising, with a view to improving the elimination of distortion at 160 Gb/s and above.
TL;DR: An analytical approach is presented for describing the Q-factor due to linear (group velocity dispersion, noise, and polarization-mode dispersion) as well as the dominant nonlinear effects in 10-Gb/s nonreturn-to-zero ON-OFF keying transmission systems.
Abstract: Dynamic optical communication systems require fast assessment of the signal quality of the desired path through the network. This paper presents an analytical approach for describing the Q-factor due to linear (group velocity dispersion, noise, and polarization-mode dispersion) as well as the dominant nonlinear effects in 10-Gb/s nonreturn-to-zero ON-OFF keying transmission systems
TL;DR: In this paper, the authors proposed a method based on a spectral analysis of modulation instability occurring in both normal and anomalous dispersion regime and the associated dispersive waves emitted by soliton fission.
Abstract: We describe a novel convenient technique to allow for the accurate measurement of the dispersion coefficients till fourth-order in the zero-dispersion wavelength region of single-mode optical fibers. The proposed method is based on a careful spectral analysis of modulation instability occurring in both normal and anomalous dispersion regime and the associated dispersive waves emitted by soliton fission. It simply requires a high-power tunable continuous-wave fiber laser and an optical spectrum analyzer and is able to retrieve both the sign and magnitude of dispersion coefficients with enhanced precision
TL;DR: In this paper, a stochastic model for studying the polarization-dependent gain in Raman fiber amplifiers with randomly varying birefringence as a function of the pump state of polarization and the polarization mode dispersion parameter is presented.
05 Mar 2006
TL;DR: In this paper, the authors present electrical dispersion compensation by using maximum-likelihood-sequence-estimation (MLSE) and decision-feedback-equalization for different modulation formats.
Abstract: We present electrical dispersion compensation by using maximum-likelihood-sequence-estimation (MLSE) and decision-feedback-equalization for different modulation formats. Especially, MLSE performance with strong optical filtering is investigated.
TL;DR: The authors describe a fast spectral polarimeter operating in the lightwave communications band capable of measuring both state-of-polarization and degree- of-Polarization of hundreds (up to thousands) of spectral components in parallel within milliseconds.
Abstract: The authors describe a fast spectral polarimeter operating in the lightwave communications band capable of measuring both state-of-polarization and degree-of-polarization of hundreds (up to thousands) of spectral components in parallel within milliseconds. In this paper, the design incorporates fast switching ferroelectric liquid crystals for polarization component selection on the 100-mus scale. Dispersion elements and an arrayed detector are used for wavelength-parallel sensing. Bandwidth of coverage can be scaled from a single wavelength-division multiplexed channel to more than 100 nm, and 256 spectral polarization measurements in under 1 ms are verified. Finally, a calibration algorithm is used to minimize measurement error. This instrument offers unprecedented sensing capability relevant to the monitoring and compensation of polarization-related impairments in high-speed lightwave communications
TL;DR: In this paper, the authors measured the wavelength dependences of the phase modal birefringence and the polarization mode dispersion for the LP01 and even LP11 spatial modes supported by Holey fiber.
Abstract: Employing several interferometric methods, we measured in a broad spectral range the wavelength dependences of the phase modal birefringence and the polarization mode dispersion for the LP01 and even LP11 spatial modes supported by a birefringent holey fibre. We also determined the wavelength dependence of the intermodal dispersion between the X- and Y-polarized LP01 and even LP11 spatial modes. Furthermore, using a full-vector finite-element method, we modelled all the measured dispersion characteristics and demonstrated good agreement between experimental and theoretical results.
05 Mar 2006
TL;DR: In this paper, the authors discuss dispersion and power map optimization for 42.8-Gbit/s RZ-DQPSK DWDM transmission over standard singlemode-fiber with terrestrial length fiber spans.
Abstract: We discuss dispersion and power map optimization for 42.8-Gbit/s RZ-DQPSK DWDM transmission over standard-single-mode-fiber with terrestrial length fiber spans. We experimentally show that long-haul 42.8-Gbit/s RZ-DQPSK transmission is feasible with high tolerances towards deviations in the dispersion map.
TL;DR: In this paper, a detailed study of fiber-coil-based polarization controllers (PCs) is performed and a method to deterministically calculate the PC configuration in order to transform between any two states of polarization is presented.
Abstract: A detailed study of fiber-coil-based polarization controllers (PCs) is performed. First, a method to deterministically calculate the PC configuration in order to transform between any two states of polarization is presented. In a second stage, the case in which the configuration angles are randomly changed is studied. The cases of a single PC and of the system obtained with the concatenation of several PCs are analyzed. For both cases, a general expression for the variance of the Stokes parameters is obtained. Using this expression, it is demonstrated that it is possible to achieve uniform polarization scattering using a concatenation of fiber-coil-based PCs. Finally, it is shown that fiber-coil-based PCs can be used to emulate both first- and second-order polarization-mode dispersions
TL;DR: A generalized Mueller matrix method, based on the polar decomposition of a 4X4 matrix which corresponds to a Lorentz transformation, can measure PMD accurately with a relatively larger frequency step, and the obtained data has very low noise level.
Abstract: A generalized Mueller matrix method (GMMM) is proposed to measure the polarization mode dispersion (PMD) in an optical fiber system with polarization-dependent loss or gain (PDL/G). This algorithm is based on the polar decomposition of a 4X4 matrix which corresponds to a Lorentz transformation. Compared to the generalized Poincare sphere method, the GMMM can measure PMD accurately with a relatively larger frequency step, and the obtained PMD data has very low noise level.
TL;DR: In this article, a 40-Gb/s 3R regenerator with a two-ring injection mode-locked fiber laser as the clock recovery and an electroabsorption modulator (EAM) as the reshaping optical decision gate is proposed and demonstrated.
Abstract: A 40-Gb/s 3R regenerator with a two-ring injection mode-locked fiber laser as the clock recovery and an electroabsorption modulator (EAM) as the reshaping optical decision gate is proposed and demonstrated. The cross-absorption modulation effect in a bulk EAM was also numerically modeled. Using this model, both the shape and the extinction ratio of the optical decision gate are optimized. The model is also employed to investigate the tolerance of the timing jitter, the chromatic dispersion, and the polarization mode dispersion of an all-optical 3R regenerator based on a bulk EAM decision gate. The operation margin of the 3R regenerator is presented. The theoretical results agree well with the experimental results
TL;DR: In this paper, the authors report on the latest experimental polarization characteristics of microstructured photonic crystal fibers filled with prototype nematic liquid crystal guest materials characterized by either extremely low (of the order of −005) or medium (of −02) material birefringence due to anisotropic properties of the microstructrured liquid crystal fibers switching between different guiding mechanisms.
Abstract: The present paper discusses polarization phenomena occurring in microstructrured liquid crystal fibers and in particular solid-core photonic crystal fibers infiltrated with liquid crystals We report on the latest experimental polarization characteristics of microstructured photonic crystal fibers filled with prototype nematic liquid crystal guest materials characterized by either extremely low (of the order ∼ 005) or medium (of the order ∼ 02) material birefringence Due to anisotropic properties of the microstructrured liquid crystal fibers switching between different guiding mechanisms as well as electrically and temperature-induced tuning of light propagation have been demonstrated These preliminary results hold great potential for both fiber-optic sensing and in-fiber polarization mode dispersion control and compensation