| 摘要 |
<p>An optical transmission system, especially useful in undersea applications, comprises an optical path between two terminals with one or more repeaters (10) located between the terminals for amplifying optical communications signals flowing in the optical path. The repeaters contain optical fiber amplifiers (24,26) driven by pump lasers (40,64). The average optical power produced by the pump lasers is controlled in proportion to the magnitude of electrical line current (30) produced by a controllable constant current source located in one of the terminals. This is achieved by regulator circuits (38,60) which are responsive to a signal related to the magnitude of the line current and signals related to the actual optical output of the pump lasers. The magnitude of the line current may be conveniently set at the terminals so that the lowest bit error rate is achieved in the transmission system. Alternatively, the magnitude of the line current may also be set to some minimum level to achieve an acceptable bit error rate and low pump laser and fiber amplifier aging. <IMAGE></p> |
