Browsing by Author "Chiang, Po-Yi"

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A Hierarchical Bin-Based Legalizer for Standard-Cell Designs with Minimal Disturbance
(2010)
Lee, Yu-Min
;
Wu, Tsung-You
;
Chiang, Po-Yi
;
交大名義發表
;
National Chiao Tung University
In this work, a hierarchical bin-based legalization approach, HiBinLegalizer, is developed to legalize standard cells with minimal movement. First, a chip is divided into several bins with equal size. Then, starting with the most crowed unlegalized bin, a merging procedure for bins is used to integrate bins into a cross-shape region or a square-shape region until the cell density in that region is less than a specific cell-density-threshold. After that, an efficient legalization method which simultaneously preserves the cell orders in each row and minimizes the weighted sum of movement distances is developed to legalize cells in that region to limit the movable scope. To improve the legalization quality, HiBinLegalizer refreshes the positions of legalized cells during legalization. The legalizing procedure is repeated until all cells are non-overlapped. Compared with the state-of-the-art method, Abacus, HiBinLegalizer can reduce the total movement of cells to be 48% in average and save the largest movement of cells to be 140% in average. Moreover, HiBinLegalizer can reduce the HPWL by 47% and obtain average 1.11 x runtime speed up.
Extracting photon periodic orbits from spontaneous emission spectra in laterally confined vertically emitted cavities
(2010-08-15)
Chen, Yung-Fu
;
Yu, Yan-Ting
;
Huang, Yu-Jen
;
Chiang, Po-Yi
;
Su, Kuan-Wei
We report our observation of the signature of photon periodic orbits in the spontaneous emission spectra of large-aperture vertical-cavity surface-emitting lasers (VCSELs). The high-resolution measurement clearly demonstrates that over a thousand cavity modes with a narrow linewidth can be perfectly exhibited in the spontaneous emission spectrum just below the lasing threshold. The Fourier-transformed spectrum is analyzed to confirm that the spontaneous emission spectra of large-aperture VCSELs can be exploited to analogously investigate the energy spectra of the 2D quantum billiards. (C) 2010 Optical Society of America
Post-Routing Redundant Via Insertion with Wire Spreading Capability
(2009)
Lei, Cheok-Kei
;
Chiang, Po-Yi
;
Lee, Yu-Min
;
電信工程研究所
;
Institute of Communications Engineering
Redundant via insertion is a widely recommended technique to enhance the via yield and reliability. In this paper, the post-routing redundant via insertion problem is transformed to a mixed bipartite-conflict graph matching problem, and an efficient heuristic minimum weighted matching (HMWM) algorithm is presented to solve it. The developed method not only inserts redundant vias for alive vias but also protects the dead vias by utilizing the wire spreading capability- that's to say, the method shifts wires into the empty space and adds redundant vias for dead vias to further enhance the via yield. Experimental results show that the average insertion rate of alive vias is 99.54% with a short run time, and the wire spreading technique can achieve average insertion rate to be 54.41% for dead vias.
The Influences of Boundary Shapes on Polarization Characteristics and Lasing Modes in Broad-Area Vertical-Cavity Surface-Emitting Lasers With Cryogenic Detuning: Regular Versus Chaotic Cavities
(2015-11-01)
Yu, Yan-Ting
;
Tuan, Pi-Hui
;
Chiang, Po-Yi
;
Su, Kuan-Wei
;
Huang, Kai-Feng
The broad-area rectangular-shaped and stadiumshaped VCSELs with nearly the same aspect ratio are designed to explore the influence of lateral boundary shapes on polarization states and lasing spectra with large detuning by cryogenic cooling. For the rectangular-shaped VCSEL, the lasing modes usually exhibit linearly polarized state and their far-field emissions mainly concentrate on four diagonal directions. On the other hand, the lasing modes of the stadium-shaped VCSEL generally display two orthogonally polarized states and their far-field emissions extensively spread on azimuthal directions. More intriguingly, the lasing spectra of the two devices clearly manifest the features of the energy-level distribution in regular and chaotic quantum billiards, respectively.