| 摘要 |
PURPOSE:To increase the flexibility and to improve the efficiency and reliability of an optical amplifying communication system by switching the low-loss passing direction of an optical isolator, which is used together with an optical amplifier, between a forward and a reverse direction optionally. CONSTITUTION:The optical amplification part is equipped with the optical amplifier 16 and the optical isolator 17 whose low-loss passing direction can be switched between the forward and reverse directions. Namely, a current is supplied to, for example, a coil 18 according to the light signal passing direction to apply an optical isolator main body 19 with a magnetic field Hr in the opposite direction from the permanent magnetic field H of a permanent magnet and the low-loss passing direction of the optical isolator 17 is switched by a method which inverts the low-loss passing direction of a light signal or the like. Consequently, the loss distribution of the whole optical transmission line can easily be measured and the efficiency and reliability of the optical communication system are improved. |
