Patent ID: 11870208
Assignee: NEC CORPORATION
Field: Optics (Instruments)
Classification: CPC H  G | IPC H

Claim 0:
1. An optical fiber amplifier comprising:
an optical fiber that is supplied with pumping light, amplifies an optical signal, and includes a plurality of cores in a clad;
a light source that outputs the pumping light;
a combiner that supplies the pumping light from the light source to the clad in the optical fiber and that causes the pumping light to be combined with the optical signal;
a collector that collects the pumping light that is supplied to the optical fiber but that is not absorbed by the optical fiber, without collecting the optical signal;
a monitor that monitors a modulation frequency component of the pumping light that has been collected by the collector and that has passed through the optical fiber; and
a controller that controls a state of the pumping light, wherein
the pumping light is modulated at a frequency higher than a response time of the optical fiber.