SEMICONDUCTOR MACH-ZEHNDER MODULATOR

摘要

PROBLEM TO BE SOLVED: To realize a travelling wave type semiconductor Mach-Zehnder modulator which has a wide band or is driven at a low voltage.SOLUTION: The Mach-Zehnder interferometer is formed with a first and second optical guide 203 and 204, and a first and second travelling wave type electrodes are formed on the first and second optical guide 203 and 204. The first and second travelling wave type electrodes respectively include a first regions 205 and 207 with a first element length having a first inductance and a first capacitance, and a second regions 206 and 208 with a second element length having a second inductance and a second capacitance. The second inductance is larger than the first inductance and the second capacitance is smaller than the first capacitance. The first element length and the second element length are sufficiently smaller than the operation frequency.