| 摘要 |
PROBLEM TO BE SOLVED: To reduce waveform distortion of a semiconductor optical amplifier, by arranging an optical filter in the output stage of the amplifier which filters out frequency component chirped by carrier density fluctuation of the amplifier, from the output light of the amplifier. SOLUTION: An optical filter 2 having bandpass characteristics which filters out frequency chirping components of an output light is arranged in the output stage of a semiconductor amplifier 1. The optical filter 2 may have bandpass characteristics, and, e.g. a Fabry-Perot interferometer filter and a Mach-Zehnder interferometer filter can be used. The optical spectrum of the output signal of the amplifier 1 is spread to the low frequency side by frequency chirping, and the signal waveform is distorted. As to an output signal light which has been made to pass the optical filter 2, a part of the frequency components chirped to the low frequency side is filtered out, and the signal waveform is shaped. |
