| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical transmitter the modulated optical output of which is made constant, even when an αparameter is set in matching with an optical transmission system, in order to apply the optical transmitter to an optional system and in order to compensate an optical element characteristic against time aging deterioration and to provide a highly reliable optical transmission system using the transmitter. SOLUTION: Since a light emitting element backward output luminous intensity detected by a PD 6 depends on a light emitting element drive current and an electric field absorption amount of an EA optical modulator 4 detected by an electric field absorption amount monitor 25 depends on the output light of a light emitting element 5 and an EA optical modulation drive point of a drive section 8, taking the difference between both a value of the PD 6 and a value of the electric field absorption amount monitor 25 can detect only the fluctuating components of the EA optical modulator drive point. Then a modulated light output 7 can be compensated automatically, even if the EA optical modulator drive point is changed due to control of the α parameter and fluctuations in the secular deterioration of the light emitting element, by applying a current corresponding to the fluctuation of the EA optical modulator drive point to a drive current source 10. |
