Dual laser-power-level control and calibration system for burst-mode and continuous-mode transmitter. A first signal path receives a transmit signal that also drives the transmit laser, and a second signal path receives the output of a monitor diode. The first and second signal paths include filtering so that the two signal paths have a similar frequency response. The upper and lower excursions in both signal paths are compared, and the power levels of the optical transmitter are adjusted based on those comparisons. Embodiments with one control loop and two control loops are disclosed.