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.

Reception of Dual-Spatial-Mode CO-OFDM Signal Over a Two-Mode Fiber

Abstract: We demonstrate the use of mechanical grating based mode converters to achieve two forms of dual-spatial-mode transmission: LP01 and LP11, and dual LP01 modes. High modal extinction ratio (>; 20 dB) is shown for the mode converter within a 10-nm wavelength range. We first present 107-Gb/s coherent optical OFDM (CO-OFDM) transmission over a 4.5-km two-mode fiber using LP01 and LP11 modes where the mode separation is performed optically. We then show 58.8-Gb/s CO-OFDM transmission using dual LP11 modes where the mode separation is achieved via 4 × 4 electronic MIMO processing.

Mode conversion enables optical pulling force in photonic crystal waveguides

Abstract: We propose a robust scheme to achieve optical pulling force using the guiding modes supported in a hollow core double-mode photonic crystal waveguide instead of the structured optical beams in free space investigated earlier. The waveguide under consideration supports both the 0th order mode with a larger forward momentum and the 1st order mode with a smaller forward momentum. When the 1st order mode is launched, the scattering by the object inside the waveguide results in the conversion from the 1st order mode to the 0th order mode, thus creating the optical pulling force according to the conservation of linear momentum. We present the quantitative agreement between the results derived from the mode conversion analysis and those from rigorous simulation using the finite-difference in the time-domain numerical method. Importantly, the optical pulling scheme presented here is robust and broadband with naturally occurred lateral equilibriums and has a long manipulation range. Flexibilities of the current co...

Adaptive mode control of a few-mode fiber by real-time mode decomposition.

Abstract: A novel approach to adaptively control the beam profile in a few-mode fiber is experimentally demonstrated. We stress the fiber through an electric-controlled polarization controller, whose driven voltage depends on the current and target modal content difference obtained with the real-time mode decomposition. We have achieved selective excitations of LP01 and LP11 modes, as well as significant improvement of the beam quality factor, which may play crucial roles for high-power fiber lasers, fiber based telecommunication systems and other fundamental researches and applications.

Helicon modes in a cylindrical plasma source

Abstract: The axial wavelengths and azimuthal mode structures of a cylindrical helicon plasma source have been investigated over a broad range of input conditions (pressure 1-16microbar, field 0-450 G, rf power 0-2500 W @ 13.56 MHz) in an argon plasma. Several distinct modes of operation, separated by discontinuous jumps, have been identified: an electrostatic mode, an m = 0 wave mode and three m = 1 helicon wave modes. Two different types of mode jump have also been identified. A cavity mode transition has been identified in which a mode jump occurs when the wavelength of standing waves governed by the length of the plasma vessel leads to a node in the wave field at the centre of the antenna. A radial mode transition has also been identified in which the favourable condition that the axial wavelength should be equal to twice the length of the antenna for efficient coupling of the rf power is maintained at high powers by the plasma making a transition from the first to the second radial mode. A procedure based on these observations is suggested for predicting where mode transitions are likely to occur within the parameter space of a helicon source.