Showing papers on "Polarization mode dispersion published in 1981"
TL;DR: It is shown that whereas a conventionally twisted fiber possesses considerable optical rotation, a fiber which has a permanent twist imparted by spinning the preform during fiber drawing exhibits almost no polarization anisotropy, making it possible to virtually eliminate the commonly observed fiber linear birefringence.
Abstract: A theoretical and experimental analysis of the polarization properties of twisted single-mode fibers is presented. It is shown that whereas a conventionally twisted fiber possesses considerable optical rotation, a fiber which has a permanent twist imparted by spinning the preform during fiber drawing exhibits almost no polarization anisotropy. It is thus possible to virtually eliminate the commonly observed fiber linear birefringence. As a consequence, fibers made in this way are ideally suited for use in the Faraday-effect current transducer. It is further shown that a permanent twist of a few turns/meter effectively eliminates polarization mode-dispersion. The technique therefore appears attractive for enhancing the bandwidth of very long unrepeatered telecommunication links.
283 citations
TL;DR: In this paper, the predictions of the nonlinear Schrodinger equation have been tested by passing 5.5psec optical pulses through a 70m single-mode optical fiber, and dramatic reshaping of the input pulses into flat-topped, frequency-broadened, and positively chirped 20psec output pulses with self-steepened fall times of less than 2 psec was observed.
Abstract: The predictions of the nonlinear Schrodinger equation have been tested by passing 5.5-psec optical pulses through a 70-m single-mode optical fiber. With use of a precise cross correlation technique based on pulse compressions, dramatic reshaping of the input pulses into flat-topped, frequency-broadened, and positively chirped 20-psec output pulses with self-steepened fall times of less than 2 psec was observed. The observations are in good agreement with theory.
265 citations
TL;DR: In this article, the theoretical and practical limits of the maximum transmission bandwidth in single-mode fibers were investigated from both the theoretical as well as the practical point of view, and a comparison between the chromatic dispersion and the polarization mode dispersion was made.
Abstract: We consider the question of the maximum transmission bandwidth in single-mode fibers from the theoretical as well as practical point of view. First, we show that there is an optimal input pulsewidth which gives minimum output pulsewidth and, therefore, determines the theoretical maximum transmission bandwidth. Both the first- and second-order dispersion terms are taken into account in calculating the optimal input pulsewidth, the optimal (minimum) output pulsewidth, and the corresponding maximum information rate for given fiber and source parameters. Next, we consider increasing the maximum transmission bandwidth by shifting the fiber's dispersion minimum to the desired wavelength, utilizing the doping and waveguide dispersion shifts. For long concatenated single-mode fibers, we also consider dispersion minimization using optical pulse equalization by purposely connecting fibers with positive and negative dispersion characteristics in series. Lastly, we consider polarization mode dispersion due to birefringence associated with fiber core ellipticity and asymmetrical stress. Based on these dispersion considerations, practical numerical examples are given, and a comparison between the chromatic dispersion and the polarization mode dispersion is made. The practical limit to the maximum transmission bandwidth in single-mode fibers is discussed.
89 citations
TL;DR: In this paper, a method to measure polarisation mode dispersion was described, in which the accuracy was more than 0.1 ps and the result was compared with the retardation obtained for a short length of the fibre.
Abstract: A new method to measure polarisation mode dispersion is described, in which the accuracy is more than 0.1 ps. 0.17 ps polarisation mode dispersion was obtained for about 1 km length of fibre. The result is compared with the retardation obtained for a short length of the fibre.
45 citations
TL;DR: In this paper, the authors measured the wavelength dependence of fiber birefringence in 1 km long single-mode fibers and explained the measured wavelength dependence by a theory taking into account elliptical core deformation.
Abstract: Polarization dispersion in 1 km long single-mode fibers is measured by observing the wavelength dependence of fiber birefringence. A typical measured value is 0.24 ps/km at the 1.2 μm wavelength. The measured wavelength dependence of polarization dispersion is explained well by a theory taking into account elliptical core deformation. Fitted core ellipticity values for the two test fibers are 0.012 and 0.003.
16 citations
TL;DR: In this article, a spatial technique based on a visibility maximum position measurement in an interferometer was used to measure the wavelength dependence of the modal dispersion by varying optical source wavelengths between 821 and 904 nm.
Abstract: Polarisation mode dispersion in elliptical-core single-mode fibres has been measured by a spatial technique based on a visibility maximum position measurement in an interferometer. Using the technique, wavelength dependence of the modal dispersion has been measured by varying optical source wavelengths between 821 and 904 nm. As a result, contribution of geometrical and strain birefringences on the modal dispersion has been evaluated, and normalised frequency dependence of the modal dispersion has been clarified.
12 citations
TL;DR: It is shown that, by using fibers with positive and negative chromatic dispersion, the first-order dispersion term cancels out on average.
Abstract: Optical pulse equalization in single-mode fibers using positive and negative chromatic dispersion has been demonstrated by Lin et al. [
Opt. Lett.5,
476 (
1980)]. In this paper, an earlier theory of pulse propagation in single-mode fibers is extended to the case of a tandem arrangement of N fibers with different dispersive properties. The theory includes first- and second-order dispersion. It is shown that, by using fibers with positive and negative chromatic dispersion, the first-order dispersion term cancels out on average.
11 citations
TL;DR: It is shown that the signal-to-noise ratio caused in this way is of the same order of magnitude as in suitable multimode-fiber systems.
Abstract: So-called single-mode fibers are generally bimodal in that they can propagate two modes with orthogonal polarizations. If both transverse offset and angular misalignment are present in a single-mode fiber connector, the loss will be mode dependent. Physical distortions of the fiber before a connector cause modal noise. It is shown that the signal-to-noise ratio caused in this way is of the same order of magnitude as in suitable multimode-fiber systems.
6 citations
TL;DR: In this article, conditions for maintaining polarization when pulse waves propagate in a single-mode fiber in which both nonuniformity in distribution of the core dielectric constant and cross sectional deformation exist are determined.
Abstract: Conditions are determined for maintaining polarization when pulse waves propagate in a single-mode fiber in which both non-uniformity in distribution of the core dielectric constant and cross sectional deformation exist. The coupling coefficient between the waves with left- and right-handed circular polarizations is denoted by β( = β1 − β2). Deformation of the core cross section from a perfect circle and deviation from uniform dielectric distribution can always be expanded into circumferential Fourier series. The values of β1 and β2 are determined by the second-order Fourier coefficients. The condition of invariant polarization in the fiber is β1 = β2 = 0. The condition for time-invariance of the plane of polarization is frequency independency of β1 and β2. We also study the effect of twisting of fibers satisfying these condtions. Denoting the rigidity by G, the optoacoustic constant by C and the index of refraction by N, we show that if G·C/N is frequency-independent, the degree of polarization is maintained in the fiber with invariant polarization although the plane of polarization rotates. When a fiber time-invariant polarization plane time is twisted, the characteristics remain unchanged. We show several examples of core cross-sectional shapes and dielectric distributions needed for maintaining the polarization.