| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of control terminals to one, and thereby downsize an element.SOLUTION: In a tree type optical switch structure 20 of a Mach-Zehnder type optical switch SW, a phase modulation region and a phase adjustment region are formed in one arm optical waveguide of each optical switch SW. The length of the phase modulation region is L at a first step, and L/2 at a second step. The phase difference capable of being imparted by the phase adjustment region is 0 at the first step, and 0 and -&pgr;/4 at the second step. Then, one control terminal CT1 and the electrode terminal of each optical switch SW are connected by an electric wiring LE.SELECTED DRAWING: Figure 1 |
