PUMP REDUNDANCY FOR OPTICAL AMPLIFIERS

摘要

Currently laser diode pump redundancy for an optical fiber amplifier is obtained by selectively connecting one of two diode pumps to an optical amplifier via an optical switch. When the diode laser pump which is connected to the amplifier becomes defective, the optical switch is activated, either remotely orautomatically, and the good laser diode is substituted for the defective laser diode pump. In another arrangement, two laser diodes are coupled to an optical fiber amplifier via a polarization-dependent optical coupler. In each instance, a second laser diode is required to provide pump redundancy for an optical fiber amplifier. In this invention, at least, two laser diodes are coupled via a 3dB optical coupler to supply pump power to each of the two optical fiber amplifiers simultaneously. If one of the laser diode pumps fails, the other laser diode pump is issued to provide pump power to each of the optical fiber amplifiers. Thus, with the addition of a 3dB coupler, pump redundancy for a pair of optical fiber amplifiers is obtained with only two laser diode pumps instead of the normally required four laser diode pumps. In practice, only one of the two pumps can be active, and the otherturned on only when the first pump fails. In another embodiment, the two laser diode pumps can be active at all times where each laser diode pump is operated at either full or less than full power. In the arrangement where the laser diode pumps are operated simultaneously at less than full power, when a pump failure occurs the power output of the good laser diode pump can be increased to compensate for theloss of power from the defective pump.