| 摘要 |
PURPOSE:To relax production conditions to attain a high extinction ratio by giving asymmetrical branch structures different in width to the entrance side and the exit side of an optical waveguide which forms a directional coupler of an optical switch of balanced bridge type. CONSTITUTION:Asymmetrical branch structures different in width are given to light input/output branching waveguides 1a, 1b, 2a, and 2b, and they are connected by branch waveguides 3a, 3b, 4a, and 4b having the same structure and linear waveguides 5a and 5b, thus forming the optical switch of bridge type. Refractive index controlling electrodes 6a and 6b are put on linear waveguides 5a and 5b. For example, if electrodes 6a and 6b are n-voltage and the light having an electric field intensity distribution 9a is inputted to the input branch path 1b, the output is outputted to the branch path 2b as shown by 13a; and if voltages are applied to electrodes, the output is outputted to the branch path 2a reverse. This switch is operated similarly with respect to the input from the input branch path 1a. Thus, the optical switch which has a simple structure and is superior in extinction ratio is formed. |
