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.

Method and device for reducing mode instability in an optical waveguide

Abstract: The invention relates to a method and corresponding devices for reducing mode instability in an optical waveguide (1), a light signal becoming unstable in the optical waveguide (1) beyond an output power threshold and energy being transformed from a basic mode into higher order modes. The invention proposes a reduction in temperature variation (2) along the optical waveguide (1) and/or a reduction in changes in the optical waveguide (1) that are caused by spatial temperature variation as a result of mode interference.

Mode interference and radiation leakage in a tapered parallel plate waveguide for terahertz waves

Abstract: To exploit tapered parallel plate waveguides for broadband terahertz (THz) spectroscopy, the impact of the waveguide geometry on transmission of terahertz pulses is investigated experimentally. We find that the approximation of single transverse electro-magnetic mode propagation is insufficient for describing the observed behavior. The TE02 mode plays a particularly important role. The mode composition, however, can be controlled by the gap between the waveguide plates, which affects the main loss mechanism, radiation leakage, and group velocity for the TE02 mode. Balancing the waveguide loss and coupling efficiencies results in an optimal gap for the tapered waveguide.

Method and apparatus for optical mode conversion

Abstract: A mode conversion apparatus including a dynamic waveguide section associated with a plurality of control elements that, when activated, are able to produce a periodic refractive-index perturbation pattern in the dynamic waveguide section, wherein the periodic refractive-index perturbation pattern is able to convert at least a fraction of an input signal from a first guided mode of the dynamic waveguide section into a second guided mode of the dynamic waveguide section.

Mode splitter and a magneto-optical disk pick-up device having the mode splitter

Abstract: A mode splitter and the magneto-optical pick-up device including the mode splitter are provided. The mode splitter includes a tapered waveguide portion whose thickness gradually becomes thin so that a light of at least one mode can be cut off. An emission position of a light wave can be varied depending on its mode. In this mode splitter, the emission position of the light wave of each mode can be adjusted by changing a thickness of the tapered waveguide, thereby improving the degree of freedom in designing the device.

A Method for Gyrotron Beam Coupling into a Corrugated Waveguide

Abstract: In the radio-frequency (rf) power transmission system of an electron cyclotron heating and current drive (EC H&CD) system, the gyrotron power should couple with the fundamental mode of the corrugated waveguide (HE11 mode) because unwanted higher-order modes affect the beam radiation characteristics, which is a problem in the quasi-optical launcher design. To achieve high HE11 mode purity, a beam coupling method that measures the transmission mode in the waveguide was examined using a 170-GHz high-power gyrotron for the first time. In beam coupling, the offset and tilt angle of the input beam at the waveguide inlet were minimized by controlling the angles of the mirrors in the matching optical unit (MOU) to minimize unwanted LP11 modes in the waveguide. The rf field profile in free space after 1.3 m of the waveguide from the MOU was measured, and the transmission mode content was analyzed. According to the analyzed mode content, the HE11 mode content was optimized by remote adjustment of the mirror...