In order to reduce transmission loss of the optical waveguide in Mach-Zehnder (M-Z) electro-optical (EO) polymer modulator,the basic iterative formula of semi-vector finite-difference beam propagation method (FD-BPM) ...In order to reduce transmission loss of the optical waveguide in Mach-Zehnder (M-Z) electro-optical (EO) polymer modulator,the basic iterative formula of semi-vector finite-difference beam propagation method (FD-BPM) is obtained from the scalar wave equation. The transition waveguide is combined with S-type bend branch waveguide for the M-Z EO modulator in the branch waveguide. The effects of structure parameters such as ridge width,length of the branch waveguide and interferometer spacing on the transmission loss are systematically studied by using the semi-vector FD-BPM method. The structure is optimized as an S-sine bend branch waveguide,with rib width w=7μm,length of branch waveguide L=1200μm and interferometer spacing G=22 μm. The results show that the optimized structure can reduce transmission loss to 0.083 dB,which have a certain reference value to the design of optical waveguide in M-Z polymer modulator.展开更多
We present the solution approach developed by the team“TheAntipodes”during the 12th edition of the Global Trajectory Optimization Competition(GTOC12).An overview of the approach is as follows:(1)generate asteroid su...We present the solution approach developed by the team“TheAntipodes”during the 12th edition of the Global Trajectory Optimization Competition(GTOC12).An overview of the approach is as follows:(1)generate asteroid subsets,(2)chain building with beam search,(3)convex low-thrust trajectory optimization,(4)manual refinement of rendezvous times,and(5)optimal solution set selection.The generation of asteroid subsets involves a heuristic process tofind sets of asteroids that are likely to permit high-scoring asteroid chains.Asteroid sequences“chains”are built within each subset through a beam search based on Lambert transfers.Low-thrust trajectory optimization involves the use of sequential convex programming(SCP),where a specialized formulationfinds the mass-optimal control for each ship’s trajectory within seconds.Once a feasible trajectory has been found,the rendezvous times are manually refined with the aid of the control profile from the optimal solution.Each ship’s individual solution is then placed into a pool where the feasible set that maximizes thefinal score is extracted using a genetic algorithm.Ourfinal submitted solution placedfifth with a score of 15,489.展开更多
基金supported by the National High Technology Research and Development Program of China (No.2009AA03Z413)
文摘In order to reduce transmission loss of the optical waveguide in Mach-Zehnder (M-Z) electro-optical (EO) polymer modulator,the basic iterative formula of semi-vector finite-difference beam propagation method (FD-BPM) is obtained from the scalar wave equation. The transition waveguide is combined with S-type bend branch waveguide for the M-Z EO modulator in the branch waveguide. The effects of structure parameters such as ridge width,length of the branch waveguide and interferometer spacing on the transmission loss are systematically studied by using the semi-vector FD-BPM method. The structure is optimized as an S-sine bend branch waveguide,with rib width w=7μm,length of branch waveguide L=1200μm and interferometer spacing G=22 μm. The results show that the optimized structure can reduce transmission loss to 0.083 dB,which have a certain reference value to the design of optical waveguide in M-Z polymer modulator.
文摘We present the solution approach developed by the team“TheAntipodes”during the 12th edition of the Global Trajectory Optimization Competition(GTOC12).An overview of the approach is as follows:(1)generate asteroid subsets,(2)chain building with beam search,(3)convex low-thrust trajectory optimization,(4)manual refinement of rendezvous times,and(5)optimal solution set selection.The generation of asteroid subsets involves a heuristic process tofind sets of asteroids that are likely to permit high-scoring asteroid chains.Asteroid sequences“chains”are built within each subset through a beam search based on Lambert transfers.Low-thrust trajectory optimization involves the use of sequential convex programming(SCP),where a specialized formulationfinds the mass-optimal control for each ship’s trajectory within seconds.Once a feasible trajectory has been found,the rendezvous times are manually refined with the aid of the control profile from the optimal solution.Each ship’s individual solution is then placed into a pool where the feasible set that maximizes thefinal score is extracted using a genetic algorithm.Ourfinal submitted solution placedfifth with a score of 15,489.
