| 摘要 |
PROBLEM TO BE SOLVED: To form a superior modulated optical wave form, having a large extinction ratio and thereby to prevent deterioration of a communication quality, even in a case where the driving power of an input electrical signal into an optical module is insufficient. SOLUTION: The module is provided with an exciton absorbing type semiconductor optical modulation device 1; a transmission line substrate 2, which feeds differential signals which have phases reversed to each other to the semiconductor optical modulation device 1 via transmission lines 2a and 2b and a wire 5; a terminal resistance substrate 3, which matches the impedance accompanying the feeding of an electrical signal, a coupling optical system for input 4a, which inputs a coupled optical input signal to the semiconductor optical modulation device 1; and a coupling optical system for output 4b which outputs a couplingly modulated optical signal which is modulated with the semiconductor optical modulation device 1. A pair of electrodes 6a and 6b are provided at the semiconductor optical modulation device 1, differential signals which are reverse to each other in phase are supplied to electrodes 6a and 6b respectively, a signal amplitude, in which the respective reverse-phased differential signals in the semiconductor is synthesized to two times in magnitude in a same vector direction, is formed, and thus a modulated optical wave form having a large extinction ratio is formed. |
