Patent ID: 8611761

Claim:
A method to control an optical transmitter that provides an auto-temperature controlling ATC loop including a temperature sensor, a first comparator, a first switch, a TEC driver, a TEC, and a temperature controller to control a temperature of an LD installed within said optical transmitter and an auto-power controlling (APC) loop including a monitor PD, a second comparator, a second switch, an LD driver, said LD, and a power controller to control an optical output of said LD, said method comprising steps of: setting said APC loop in an open loop mode and said LD in a constant driving condition when said ATC loop becomes extraordinary, by switching said second switch from a mode in which said LD driver is connected to said second comparator, to another mode in which said LD driver is connected to said power controller, and providing a control signal from said power controller to said LD driver, said control signal corresponding to a driving current provided just before said ATC loop becomes extraordinary providing an output of said monitor PD to said temperature controller; and controlling said temperature of said LD based on said optical output of said LD by switching said first switch from a mode in which said TEC driver is connected to said first comparator, to another mode in which said TEC driver is connected to said temperature-controller, and providing another control signal to said TEC driver from said temperature-controller, said another control signal corresponding to said output of said monitor PD.