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.

Investigation of Mode Coupling in Graded Index Plastic Optical Fibers Using the Langevin Equation

Abstract: By employing the Langevin equation, we have examined a mode coupling in graded index plastic optical fiber. The numerical integration of the Langevin equation is based on the computer-simulated Langevin force. The solution matches the experimental data reported previously. We have shown that by solving the Langevin equation (stochastic differential equation) one can treat a mode coupling in graded index plastic optical fibers, which is result of fiber's intrinsic random perturbations.

Femtosecond inscribed mode modulators in large mode area fibers: experimental and theoretical analysis

Abstract: We present the experimental and theoretical analysis of a mode modulator in a few mode LMA fiber. The mode modulator consists of a section with a modified refractive index alongside the fiber core in the cladding, disturbing the guidance of the modes in the core. The extent of excitation of these disturbed modes depends on the overlap of the excited undisturbed and disturbed modes. At the end of the modulator, undisturbed modes will be excited again in the fiber core, in dependency of the spatial field distribution of the disturbed modes at the boundary. In the mode modulator disturbed higher order modes lead to modal interference, causing a dependency of the spatial distribution of the light in the mode modulator on the propagation length of the disturbed modes. Hence, the modal output field depends on the length of the mode modulator. For the experiments, the mode modulator was inscribed directly into the LMA fiber with ultrashort laser pulses. During the inscription process the modal content at the end of the fiber was measured using a computer generated hologram as a correlation filter. In dependency of the length of the modulator strong oscillations between the content of the fundamental and the higher order modes are observable. In the case of an initially excited fundamental mode, its content could be reduced to below 5%, whereat the content of the LP11 modes was up to 90%. While measurement and simulation show qualitative agreement, differences are caused by inhomogeneities of the refractive index modifications.

Few-mode optical transmission systems in the visible band

Abstract: This paper introduces the principles and current technology of few-mode transmission in guided optical medium for systems operating in the visible band. The visible band opens up the possibility of using standard single mode fibre, as few-mode propagation media, with the advantage of lower cost than equivalent C+L components. Few-mode transmission performance is analysed in detail considering the propagation of two degenerated modes with modal and chromatic dispersion transmission impairments. The results indicate that few-mode optical transmission systems can be used as high-capacity optical interconnects and high-performance computing networks providing 1 Gbps at 322 m operating at 850 nm or 10 Gbps at 11.8 km with 1064 nm.

Structure Mode Geometrical Identification and Application

Abstract: Frequency and mode are character parameters of structure, and mode is also self-contained coordinate basis vector of displacement, so mode can be used for concept design and mechanical design. Through depth-width ratio from one to seven, results indicate the whole deformation of structure varies from shear mode to bend mode gradually; except for vertical mode, general mode is not one deformation, it is coupled by several deformations and one deformation ratio is dominant. During three of depth-width ratio, structure deforms in shear mode, so masonry structure should be in that range. In order to exerting reinforced concrete and steel material property and energy consumption capacity, the depth-width ratio should be from three to seven. For depth-width ratio between five and seven, the first eight modes is the same, manifesting mode has convergence property.

Coupling of fiber-waveguide amplifier

Abstract: High efficient coupling between waveguide amplifier and single mode fiber is an important aspect for component integration in the optical communication. Mode matching degree between waveguide and fiber straightly affects coupling loss and actual light intensity distribution in waveguide. In this paper, Bessel function field in step refractive index fiber excites erbium-doped Al 2 O 3 rib waveguide amplifiers on silicon substrate with SiO 2 buffers with large refractive index changes. Rib height is selected 0.8μm for 1μm film thickness and 3μm rib width waveguide amplifier for single mode operation at signal wavelength. Signal and pump guided modes are calculated by finite element method. Mode excitation fractions of signal and pump are obtained. The dependences of coupling loss and subsequent gain on fiber core radius and fiber-waveguide offset are analyzed in detail. The coupling losses between fiber and three different geometry structure waveguide amplifiers (rectangle, trapeze, trapeze upside down) with the same active core cross-section area are compared. The gains of corresponding waveguide amplifiers are compared as well as.