摘要 |
An optical fiber amplifier whose characteristics are stable is provided. The optical fiber amplifier provides a short wavelength transmitting coupler that multiplexes pumping light inputted from its forward side and inputted signal light, an EDF that amplifies the signal light inputted from the short wavelength transmitting coupler, a narrow-band coupler that multiplexes the signal light and the pumping light in the transmission band of the narrow-band coupler, a splitting coupler that splits the inputted pumping light at a designated ratio, and a pumping light LD that outputs the pumping light for amplifying the signal light. With this structure, at the optical fiber amplifier that amplifies many wavelengths together being adopted at the WDM transmission, even when the number of input signals is changed, the deterioration of noise figure is avoided.
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