| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical modulator which has high-performance optical modulation characteristics and is improved with respect to stability. SOLUTION: The optical modulator includes a substrate 1 having an electro-optical effect, a buffer layer 2 formed on the substrate, a traveling wave electrode 4 which is disposed above the buffer layer and comprises a center conductor 4a and grounding conductors 4b and 4c, and a ridge portion formed by a recess provided by digging down at least a part of the substrate in an area wherein a field intensity of a high frequency electric signal propagated through the traveling wave electrode is high. The ridge portion includes a ridge portion 8a for the center conductor, above which the center conductor is formed, and a ridge portion 8b for grounding conductors, above which the grounding conductors are formed. A grounding conductor 4b<SP>(5)</SP>for connection in the recess is made thicker, and an electrode including the center conductor 4a and a grounding conductor 4b<SP>(4)</SP>is disposed symmetrically with respect o a center line V of optical waveguides 3a and 3b. COPYRIGHT: (C)2009,JPO&INPIT
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