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.

Waveguide mode coupler for separating waves of useful mode from waves of higher mode

Abstract: A mode coupler useful in ranging systems for evaluating higher waveguide wave modes resulting from aperture deviations of an antenna exciter for determining angular deviation in the azimuth plane as well as in the elevation plane. Waves of the useful mode are separated from waves of a higher mode. A first waveguide section for propagating all evaluatable wave modes is adapted to be coupled to an antenna. A second waveguide section for propagating exclusively the useful wave mode is connected in series with the first waveguide section. A gap is provided between the first waveguide section and the second waveguide section and is provided with a plurality of apertures for the higher wave modes in the direction of propagation of the waves. New modes corresponding to the higher wave modes are substantially excited by the useful mode containing the ranging signal.

Mode coupling in low NA plastic optical fibers

Abstract: Using the power flow equation and experimental measurements, investigated in this article is the state of mode coupling in low NA (0.3) step-index plastic optical fibers for laser beam launch. Results show the coupling length L c at which the equilibrium mode distribution is achieved and the length z s of the fiber required for achieving the steady-state mode distribution. Numerical results obtained using the power flow equation agree well with experimental measurements.

Integrated fiber-based transverse mode converter

Abstract: A transverse mode converter based on a binary micro relief implemented directly on the endface of a few-mode fiber was numerically investigat ed. The results of numerical simulation demonstrated the converter to form LP-11 and LP-21 modes with high efficiency, providing a more-than 92 % mode purity. Transformations of modes excited by a fiber microbending were also numerically investigated. The excited beams were sh own to save their mode purity even in a strong bending as the arising parasitical modes wer e mostly unguided by the fiber. The resulting beam power and mode content were also demonstrated o depend on the beam and bending mutual orientation for beams with strong rotational symmet ry.

Analysis of the cross-coupled lateral mode in a twin-stripe four-contact laser with diagonal current injection

Abstract: Cross-coupled resonant lateral modes in a twin-stripe four-contact laser are analyzed by coupled-mode theory for conditions in which the current injection into each diagonal pair of stripes is equal. The dependence of the optical power distribution on the laser length and on the carrier-density or the current-density distribution is investigated. The most interesting result is that the highest optical power interesting result is that the highest optical power appears in the waveguide with the lowest carrier density when the carrier-density difference between the adjacent waveguides is small and the laser is shorter than the coupling length. This makes it possible to show that a cross-coupled mode can be supported even in a two-contact twin-stripe laser and that bistable switching between the mode and its mirror image is possible. >

Influence of the angle-dependence of mode coupling on optical power distribution in step-index plastic optical fibers

Abstract: Determination of the power distribution in step index plastic optical fibers by the power flow equation has been reported in the literature both with and without the simplifying assumption of constant coupling that is independent of the angle of light propagation The need for this assumption is evaluated in this paper Results with the angle-dependent coupling coefficient are compared to those derived under the simplifying assumption of constant coupling Benchmarked to values measured experimentally, this comparison covered the coupling lengths Lc (denoting where the equilibrium mode distribution is achieved in the fiber) and lengths zs (for achieving the steady-state distribution) Results differ slightly but only for longer fiber lengths, thus largely vindicating the simplifying assumption of constant coupling