Patent ID: 7042634
Filing Date: 2006-05-09
Classification: H01S,H04B

Abstract:
1. An optical amplifier comprising a rare-earth doped optical fiber or rare-earth doped optical waveguide serving as an amplification medium where rare-earth ions have been doped in its core and/or clad, an excitation means for exciting the amplification medium, one or more control light source that can control population inversion state of the amplification medium by inputting a control light with a wavelength in the amplification band of the amplification medium into the amplification medium and changing a power of the inputted control light, a monitor means that monitors powers of lights inputted into and outputted from the amplification medium, and a control unit where a gain is calculated from lights inputted into or outputted from the amplification medium from values from the monitoring means and controls the control light source so that the calculated gain is matched with a prescribed value or an externally decided value.