Patent attributes
A broad-band light source has a reduced tendency to oscillate and has high efficiency. The broad-band light source comprises (a) an optical waveguide that comprises a optical active element to generate an ASE lightwave when a pumping lightwave is supplied, that outputs an ASE lightwave in a first wavelength band from its first end, and that outputs an ASE lightwave in a second wavelength band from its second end, (b) a pumping lightwave-supplying means for supplying a pumping lightwave to the optical active element, and (c) a lightwave-combining means that receives the ASE lightwave in the first wavelength band, that receives the ASE lightwave in the second wavelength band, that combines the received ASE lightwaves, and that outputs the resultant ASE lightwave.