| 摘要 |
PURPOSE:To obtain the optical modulator which is excellent in modulation efficiency and is short in element length by forming the light guide in at least an exit part to the light guide width smaller than the light guide width of an arm part. CONSTITUTION:The light guide 12 formed on a substrate is constituted of an incident part 12a, branch parts 12b, the arm part 15 consisting of the light guide made into two guides by the branch parts 12b, a confluent part 12c where the two light guides join to one, and a piece of the exit part 16 connected to the confluent part 12c and has a means for changing the refractive index of the light guide of the arm part 15 on the arm part 15. The exit part 16 is formed to have the light guide width smaller than the light guide width of the arm part 15. The modulation efficiency is improved in this way and the small-sized optical modulator which shortens the electrode length is obtd. |
