Showing papers on "Polarization mode dispersion published in 1980"

Wavelength dispersion characteristics of single-mode fibers in low-loss region

Abstract: Wavelength dispersion characteristics of single-mode silica fibers in a very low-loss region, including zero dispersion wavelengths, are studied in detail using a "difference method." Wavelength dispersion of single-mode fibers is compared for fibers with same material dispersion but with different waveguide structure. Material dispersion is evaluated by extracting waveguide dispersion from experimental results. Effects of waveguide dispersion on the zero dispersion wavelength of the single-mode fiber in a longer wavelength region are clearly analyzed. Single-mode fiber design consideration is given from the wavelength dispersion point of view.

Characteristics of dispersion free single-mode fiber in the 1.5 µm wavelength region

Abstract: Characteristics of dispersion free single-mode fibers in the wavelength regions 1.5 and 1.3 μm are compared experimentally and theoretically. We consider the influence of the refractive index profile on dispersion, the tolerance limits of structure parameters for minimum dispersion, attainable fiber bandwidth, and transmission loss including splicing and bending losses. For a fiber designed for minimum dispersion at 1.5 μm, the measured fiber loss was less than 1 dB/km and bandwidth was 250 GHz. km. nm. The achievable minimum loss estimation shows the advantage of dispersion free fibers at the 1.5 μm wavelength over dispersion free fibers at 1.3 μm.

Correlation between numerical predictions and measurements of single-mode fiber dispersion characteristics

Abstract: Exact numerical solutions for the LP01 propagating mode of the scalar wave equation are used to calculate propagation constants in single-mode fibers with arbitrary refractive-index profiles. The procedure is used to correlate predicted chromatic dispersion properties of single-mode fibers based on interferometrically measured profiles with direct transmission measurements vs wavelength. Resulting waveguide dispersion effects are used to design single-mode fibers that have minimum chromatic dispersion at desired wavelengths within the 1.3–1.6-μm region.

Pulse broadening in long-span dispersion-free single-mode fibres at 1.5 μm

Abstract: Dispersion-free single-mode fibres at 1.5 μm were fabricated by controlling their waveguide dispersion and dopant-dependent material dispersion. Pulse broadening in the 20 km long fibre was measured by using a laser diode operated at 1.5 μm. Measured pulse broadening was 1.3 ps/km nm, which is in good agreement with theoretical results. The present experiment confirms that it is beneficial to use such fibres for large-capacity and long-distance transmission media.

Minimization of Modal Dispersion in Graded-Index Fibers over a Wide Wavelength Range

Abstract: A new type of index profiles is proposed, which can minimize modal dispersion of multimode optical fibers over an extended spectral range. We deal with a wide class of dopant profiles having an arbitrary distribution in the core. The optimum profiles of the dopant materials are investigated for GeO2 + P2O5 doped silica fibers using numerical calculation. It is shown that a r.m.s. (root mean square) pulse broadening can be reduced to 0.02 ns/km between 0.6 μπι and 1.7 μπι in the gradedindex fibers with the optimized dopant concentration distribution. 2 Theory

Pulse dispersion in a clad lens-like medium

Abstract: The effects of a homogeneous cladding on the dispersion of a square-law dielectric guide are investigated using a perturbation technique. Assuming a Gaussian, band-limited input it is shown that for single mode operation the waveguide dispersion is of the order of the material dispersion. For multimode operation the effect of the cladding on the uniformly polarized modes is examined and it is shown that a significant interaction occurs only for the two modes closest to cut-off. Comparison is made between theoretical and experimental results. The perturbation technique is used to analyse the optimum index profile proposed by Okamoto and Okoshi. It is shown that this variation reduces the dispersion to below that of the infinite medium approximation.