| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical transmitter that can perform a stable phase shift amount (operation point) adjustment by preventing an error detection of an orthogonal control optimum point due to average value variations of a phase modulation light that has been a problem in conventional optical transmitters.SOLUTION: Signal correction means 40 including a branch part 39, an LPF 32 and an adder (subtracter) 33 is disposed in a control loop 22 of an optical transmitter. The branch part 39 branches an electrical signal b3 obtained by a monitor PD 31 into a first branch signal b3-1 and a second branch signal b3-2. The LPF 32 obtains an average value b4 of the second branch signal b3-2 by allowing a low frequency component of the second branch signal b3-2 to pass therethrough, while removing high frequency component from the second branch signal b3-2. The adder 33 obtains a corrected monitor signal b5 by subtracting the average value b4 of the second branch signal b3-2 obtained by the LPF 32 from the first branch signal b3-1. |
