Abstract: An apparatus and method for controlling laser power in an optical recording system in the presence of mark length variations produced by a groove wobble when an incident recording beam is off-track. An optical source supplies an incident write signal to an optical medium, such that data may be recorded on the medium during an incident write pulse as an optically-detectable mark. A reflection of the incident write signal from the medium is detected to provide a reflected write signal. A mark formation effectiveness (MFE) signal is generated from the reflected write signal to provide an indication of mark formation. A feedback circuit connected between the signal generator and the optical source controls a power level of the source in accordance with MFE signal variations produced by the wobbled groove.