Patent ID: 8363308

Claim:
A fiber optical device comprising: an amplification optical fiber that includes a core containing a laser active substance; a seed light source for supplying pulse seed light to the amplification optical fiber; an excitation light source for supplying excitation light for the laser active substance to the amplification optical fiber; a bleaching light source for supplying, to the amplification optical fiber, bleaching light for reducing a light transmission loss caused by photodarkening; and control means that controls mutual timing of the supply of the pulse seed light from the seed light source to the amplification optical fiber, the supply of the excitation light from the excitation light source, and the supply of the bleaching light from the bleaching light source, wherein the pulse seed light is supplied to the amplification optical fiber that is brought into a population inversion state by the supply of the excitation light such that an output light pulse resulting from the amplification of the pulse seed light is generated and output, and the control means divides a period between a first output light pulse and a succeeding second output light pulse into a plurality of periods including a first period which includes a time point immediately after an output of the first output light pulse and during which the population inversion in the amplification optical fiber is unsaturated and a second period which includes a time point immediately before an output of the second output light pulse, supplies the bleaching light from the bleaching light source to the amplification optical fiber in the first period, and supplies the excitation light from the excitation light source in the second period.