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AssigneeNikon Corporation
InventorAkira Tokuhisa
Estimating the term…
A polarization state adjusting optical element is formed by a ½ wavelength plate and a ¼ wavelength plate and its polarization direction and elliptic degree are adjusted. By adjusting the polarization state adjusting optical element in advance, even if the output of a pump light source is changed, the polarization characteristic (polarization direction and elliptic degree) of the output light of an FDFA amplifier will not not change or the change is sufficiently small. In this state, a polarization state adjusting optical element adjusts the polarization state of the laser beam coming into a wavelength conversion optical system so that the wavelength conversion optical system has the maximum conversion efficiency. Thus, it is possible to provide an FDFA having a small change of the polarization state of the output light even if the pump light intensity is changed.
An optical fiber amplifier, wherein the polarization state of an input light is adjusted in such a way that the polarization state of an output light will not change even if an amplification factor is changed.
An optical fiber amplifier, comprising a polarization state adjusting optical element which adjusts the polarization state of an input light in such a way that the polarization state of an output light will not change even if an amplification factor is changed.
A light source device which optically amplifies a laser beam generated from a laser light source by an optical fiber amplifier and allows the optically amplified light to be incident on a wavelength conversion optical system to obtain an output light having a predetermined wavelength, comprising light separation means for taking out a portion of the output light as a monitor light, and a light intensity adjusting device which manipulates the intensity of an excitation light supplied to the optical fiber amplifier in such a way that the intensity of the monitor light taken out by the light separation means is kept at a target value, wherein a polarization state adjusting optical element is arranged between the laser light source and the optical fiber amplifier.
Dependencies are inferred from the claim text.