| 摘要 |
<p>An optical transmission device which fetches drive control data corresponding to a temperature detected by a temperature detector (112) from a memory means (173), and controls a drive current to be fed to a laser diode (100) on the basis of the drive control data. The optical transmission device measures a drive current actually fed to the laser diode, the light emitting intensity of which is made constant by automatic optical output control circuits (115, 113), and updates the drive control data relating to the temperature on the memory means, when a difference between the measured drive current and a drive current determined by the drive control data according to the detected temperature exceeds an allowable range, so that the difference thus obtained may be designated as the individual increments of a bias current and a modulated current. For deciding the deterioration of the laser diode, the progress of the laser diode deterioration is decided on the basis of the difference between the drive current designated by the drive control data according to a newly measured temperature, and the actual drive current produced by an automatic optical output control. Thus, the drive control data corresponding to an ambient temperature can be updated by reliably discriminating whether the increase in the drive current by the automatic optical output control is caused by the deterioration of the laser diode or by the change in the temperature.</p> |
