Optical Design for Orthogonal Aperture-Multiplexed Waveguide Holography

Abstract

We study the level spacing distribution p(s) in the spectrum of random networks. According to our numerical results, the shape of p(s) in the Erdős-Rényi (E-R) random graph is determined by the average degree k and p(s) undergoes a dramatic change when k is varied around the critical point of the percolation transition, k = 1. When k 1, the p(s) is described by the statistics of the Gaussian orthogonal ensemble (GOE), one of the major statistical ensembles in Random Matrix Theory, whereas at k = 1 it follows the Poisson level spacing distribution. Closely above the critical point, p(s) can be described in terms of an intermediate distribution between Poisson and the GOE, the Brodydistribution. Furthermore, below the critical point p(s) can be given with the help of the regularized Gamma-function. Motivated by these results, we analyse the behaviour of p(s) in real networks such as the internet, a word association network and a protein-protein interaction network as well. When the giant component of these networks is destroyed in a node deletion process simulating the networks subjected to intentional attack, their level spacing distribution undergoes a similar transition to that of the E-R graph.

The Composite Structure of Hologram and Optical Waveguide

“…(a) (b) [Yagi, et al, 2007]. With OAM holography, the diffracted lights first concentrate in small isolated areas on the aperture plane (dashed line) and then expand and overlap on the imaging plane (solid line), as shown in Fig.…”

“…next generation of optical data storage systems, many researchers have focused on this work [Imai, et al,2003;Ishihara, et al, 2004;Mitasaki & Senda, 2006;Yagi, et al, 2007;Yagi, et al, 2008 ].…”

Tolerance for translation disturbances of template-matching two-dimensional modulation code for holographic memories

“…A reproduction method that satisfies the above conditions using two different numerical apertures ͑NAs͒ is proposed. This method is evaluated as a multilayered optical waveguide-type holographic read-only memory ͑MWH-ROM͒, [10][11][12][13] which is expected to be a compact and large-capacity content distribution ROM.…”

Two-Dimensional Constant-Weight Block Code in Orthogonal Aperture-Multiplexing for Multilayered Waveguide Holographic Memory

“…The orthogonal aperture-multiplexing (OAM) method [1][2][3] for fabricating a multilayered waveguide holographic (MWH) memory [1][2][3][4][5][6][7][8][9][10][11][12][13] has been studied to develop mass storage systems. For commercial systems, a modulation code is useful to reduce the raw bit error rate (BER), which is the BER before error-correction processing.…”

“…Many kinds of modulation codes for holographic memory equipment have been proposed. 3,[12][13][14][15][16][17][18][19][20][21][22] Two-dimensional (2D) constantweight block codes are useful for achieving a low raw BER. 3,[12][13][14][15][16][17] However, there has been no investigation of a suitable code for the OAM method for fabricating MWH memory.…”