Reflection-type Mach-Zehnder LiNbO/sub 3/ optical modulator with double-stub structure

In order to obtain low-driving-voltage band-operation optical modulators, we investigated a reflection-type Mach-Zehnder LiNbO/sub 3/ optical modulator with double-stub structure. The double-stub structure consists of a modulating electrode and two stubs. The modulating electrode has two arms of the same length, and is an asymmetric coplanar waveguide (ACPW). A feeding line, which is a coplanar waveguide (CPW), is connected at the center of the modulating electrode. Two stubs, which are also CPWs of the same length, are also connected at the junction of the modulating electrode and the feeding line, so that we call it a double-stub structure.