Showing papers on "Polarization mode dispersion published in 1986"

Measurement of spatial distribution of mode coupling in birefringent polarization-maintaining fiber with new detection scheme.

Abstract: We present a new detection scheme for measuring the spatial distribution of mode coupling in birefringent, polarization-maintaining fibers. The new method canl improve the signal-to-noise ratio by a factor of 100 compared with the previously reported heterodyne-detection scheme. As a result, origin of the mode coupling in a low-cross-talk, birefringent fiber is clarified.

A Conceptional Design on Optical Frequency-Division-Multiplexing Distribution Systems with Optical Tunable Filters

Abstract: Optical frequency-division-multiplexing distribution systems providing more than ten frequency multiplexed optical signals separated by on the order of gigahertz, distribute signals to plural receivers, where one of the signals is selected by a frequency selection switch (FS-SW). This paper describes the design of an optical frequency-divisionmultiplexing distribution system. Investigation is made of periodic filters for frequency division multiplexers and FS-SW, and the optical source, as well as single-mode fiber polarization mode dispersion. Preliminary transmission experiments using a bit rate of 450 Mbits/s, fiber length of 13 km, and frequency spacing of 11 GHz are also demonstrated at a 1.5 μm wavelength to show the design's suitability.

Birefringence and polarization mode dispersion in a coil of a single-mode fiber

Abstract: Modal birefringence introduced by lateral stress resulting from bending is evaluated experimentally as a function of bending curvature in wide region of bending radius from 2.2 to 30 mm by a technique utilizing birefringent-matching stimulated four-photon mixing at pump wavelengths of 1.06 and 1.34μm. Wavelength dependence of polarization mode dispersion is also measured in the 0.8–1.6-μm wavelength region by an improved spatial technique based on optical heterodyne detection. The results obtained experimentally on these quantities are compared with those calculated theoretically. It is found that the birefringence evaluated experimentally agrees well with that calculated theoretically, even for a bending radius as small as 2 mm. As for polarization mode dispersion, the theoretical evaluation of the normalized frequency dependence of the modal dispersion agrees well with that obtained experimentally with respect to curve tendency against the V value and the magnitude of the dispersion far from the cutoff V value. However, it is observed that the modal dispersion drastically decreases with the V value in the region of 1.6 1.2. This discrepancy is considered to be due to difference between the actual stress distribution resulting from bending and the calculated one obtained by using the slab approximation to evaluate bending-induced birefringence.

Spectral polarization method for the determination of birefringence and polarization dispersion in strongly birefringent single-mode waveguides

Abstract: It is shown that a spectral polarization method can be used to determine directly the spectral dependence of the polarization dispersion of radiation propagating along a single-mode fiber waveguide, and of the "group" birefringence proportional to this dispersion. The interpretation of the results is confirmed experimentally by a study of a model sample of a birefringent crystal and of a single-mode fiber waveguide using other methods. It is also shown that this method can be used to determine highly accurately the cutoff wavelength of a single-mode fiber waveguide.

Analysis of polarization-maintaining optical fibers with circular pits outside a circular core

Abstract: This paper investigates the polarization-maintaining optical fibers with one circular hollow pit (SCF) and two circular hollow pits (DCF) outside a circular core. The modal birefringence of the following fibers are investigated: i) with homogeneous core, ii) with radially inhomogeneous core. The relation between the modal birefringence (ΔB) and the polarization dispersion (Δτ) is also investigated. The homogeneous core fibers are analyzed by the improved point-matching method. To analyze the inhomogeneous core fibers, the core is divided into several homogeneous layers and the improved point-matching method is then applied. The main conclusions drawn in this paper are as follows: (1) the maximum modal birefringence for DCF can be attained 3.5 times larger than that for SCF; (2) the modal birefringence for inhomogeneous core fiber cannot be greater than that for homogeneous core fiber, even if the core index is chosen equal to the maximum index value of inhomogeneous core; (3) zero polarization mode dispersion can be attained near the wavelength where the modal birefringence takes the maximum value; however, it is not zero at that very wavelength. The relative error of propagation constant computed by our method is less than 10−9 so that the relative errors of the modal birefringence and polarization mode dispersion are less than 10−4.

Precision Of The Phase Shift Method For Measuring Chromatic Dispersion In Single Mode Optical Fibers

Abstract: For the multiple-source phase shift method of measuring chromatic dispersion in single mode optical fibers, the magnitude and origins of measurement errors are examined. Calculations show that worst-case errors can be caused primarily by source wavelength uncertainty for measurement of long fiber lengths with high modulation frequencies. For shorter (factory length) fibers and lower modulation frequencies both phase and wavelength uncertainty can be important error sources.

Dispersion measurement of a long-length concatenated single-mode fiber with a streak camera

Abstract: With the development of long-distance high-capacity optical communication systems using a 1.5-pm wavelength region, it is important to measure the dispersion of optical fibers with high resolution.