Patent ID: 9478935
Filing Date: 2016-10-25
CPC Classification: H01S,H04B,H04J

Claim Text:
1. An optical amplifier including a plurality of multiplexed signal lights of mutually different frequencies as input light, the optical amplifier comprising: a first detector configured to detect a power of the input light; an excitation light outputter configured to output an excitation light to amplify the input light; a second detector configured to detect the power of the amplified input light; a third detector configured to detect a power of the excitation light; and a controller configured to determine that the power of the input light is large upon the power of the excitation light detected by the third detector being greater than or equal to a first threshold, determine that the power of the input light is small upon the power of the excitation light detected by the third detector being smaller than or equal to a second threshold smaller than the first threshold, control the excitation light outputter so as to, upon determination that the power of the input light is large, make a ratio of a detection result by the second detector relative to a detection result by the first detector constant, and control the excitation light outputter so as to, upon determining that the power of the input light is small, make the detection result by the second detector substantially constant.