Methods and apparatus for control of variable optical attenuators are described. A method for control of a variable optical attenuator located in an optical link comprising a plurality of optical attenuators. The method comprises determining that an initial calibration step of a variable optical attenuator has been completed, and transmitting a signal indicative of the variable optical attenuator having completed the initial calibration step for receipt by a downstream variable optical attenuator. A method of controlling a variable optical attenuator comprises receiving a signal indicative of an upstream variable optical attenuator having completed an initial calibration step, and initiating calibration of the variable optical attenuator in response to receipt of said signal.