| 摘要 |
PURPOSE:To keep the long service life of an optical module by preparing plural light emitting elements of one channel in the optical module, and driving them by switching. CONSTITUTION:A certain laser diode (LD) in an LD module 3 is used by being selected at an LD switching circuit 2. A driving current is increased by an APC(Auto Power Control) circuit 6 according to deterioration in the LD due to its service life, etc. When the current arrives a certain value, the LD switching control circuit 5 is operated, the LD switching circuit 2 is operated, and the LD is switched to another LD in the LD module 3, and it is driven and emits light by an LD driving circuit 1. In such a way, it is possible to realize the long service life of an optical transmission module. |
