| 摘要 |
<p>A 1-input/2-output or 2-input/2-output directional coupler type optical device comprising a junction (Co) including two optical waveguides (A,B) arranged parallel to each other and each fitted with an electrode (F1,F2 F3,F4) for controlling a propagation constant, the incidence end or ends of one or both of the optical waveguides being connected to curved or straight optical waveguides (E), thus forming an incidence-side lead section, and the respective emergence ends of the two optical waveguides being optically connected to curved or straight optical waveguides (D), thus forming an emergence-side lead section. An electrode for suppressing the mode coupling is mounted on each optical waveguide of the emergence- or incidence-side lead section. A high extinction ratio of 30 dB or more can be obtained in either of cross and through modes by activating a required one of the mode coupling suppressing electrodes while applying an electrical signal to each propagation constant control electrode. <IMAGE></p> |
