| 摘要 |
An optical transmitter for use, for example in a TPON (telecommunications over passive optical networks) network, has a servo circuit for controlling the optical output power of an optical source of the transmitter. In a power setting operation used for bringing the output power to a demand level when the transmitter is first connected to the network, the servo circuit causes the source to produce a series of optical pulses and monitors the power of the pulses using an optical sensor coupled optically to the source. If the modified power level of a pulse is less than the demand level then in the next pulse the drive signal value (ID) applied to the source is increased, relative to the drive signal value for the present pulse, by a predetermined adjustment amount, whereas if the monitored power level is greater than the demand level the drive signal value is decreased by the predetermined adjustment amount. The drive signal value for the first pulse is half the full scale drive signal value, and the predetermined adjustment amount is initially one-quarter of the full scale drive signal value and is thereafter halved for each successive pulse. The power setting operation in the optical transmitter described is desirably fast and accurate.
|
