Equilibrium mode distribution

About: Equilibrium mode distribution is a research topic. Over the lifetime, 928 publications have been published within this topic receiving 14939 citations.

A Practical channel modeling method for few-mode optical fiber communication systems

Abstract: A channel modeling method is developed and proposed to practically model the various effects of mode couplings for optical communication systems with multi-core fiber (MCF) and/or few-mode fiber (FMF). The method is similar to existing channel modeling methods in which strong coupling is exclusively considered but extends them to cover both strong and weak couplings. With the method, the entire channel is divided into K statistically independent sections where each section may represent an optical device or the span of a few-mode fiber transmission line that maintains coherence. Each section is modeled by a channel matrix model comprising full random unitary matrices and a differential mode delay (DMD) matrix. To further enhance the modeling of weak coupling, the matrix is modified by segregating it into partial block matrices and inserting correlation terms among blocks. The method is evaluated with data obtained in two representative cases: midrange (40 km) and long-haul (527 km) transmissions. Its effectiveness and practicality are validated from agreement obtained between simulation and measured results for the two cases.

Dispersion-compensation fiber using higher order mode

Abstract: The fibre optic dispersion compensation has a profiled index from the fibre center to the outside, then a constant gain with profile providing mix fundamental/upper order mode propagation.

Bandwidth characteristics of optical transmission line constructed with short-length optical fibers

Abstract: This paper clarifies the bandwidth characteristics of a VAD-fabricated optical line constructed with short-length optical fibers. The refractive index profiles of these optical fibers are slightly distorted from the ideal profile. Their bandwidth characteristics are calculated and measured under the overfill mode distribution (OMD) and the equilibrium mode distribution (EMD) excitations. As a result, some of the optical fibers are shown to have extremely narrow bandwidths at the short fiber length under OMD excitation as compared with those under EMD excitation. The concatenation factor of the optical line consequently becomes a smaller value than that of an optical line constructed with long-length optical fibers. In addition, the measurement results of the optical subscriber transmission line field trial are shown to be in good agreement with those obtained in this paper.

Mode-conversion type optical Y-branching waveguides fabricated on glass substrate

Abstract: Y-branching waveguides for optical splitting and mixing have been proposed and a low loss structure of these devices have been also proposed. We have also proposed a mode conversion type Y-branching waveguide and the low loss characteristic of this device has been demonstrated by using numerical simulation based on the model of the step-index type slab optical waveguide. The device structure is based on the structural condition for the multi-mode coupling system derived from the mode coupling theory. It can be applied to waveguides other than the slab optical waveguide. In this study, it was experimentally investigated whether this method is applicable to the diffused type Y-branching optical waveguide. In the Y-branching mode converter formed on a soda-lime glass, the loss characteristic can be estimated by the mode coupling theory. The loss in this type of device is lower than that in the conventional linear Y-branching waveguide. It was also confirmed that the low loss structure used in the mode conversion type Y-branching waveguide is applicable to the diffused channel optical waveguide.