| 摘要 |
<p>In a wavelength-selective coherent receiver that can extract only a signal having a desired wavelength among from multiple wavelengths, the influence of noises is increased and the receiving sensitivity is deteriorated when the optical input power is high. A coherent light receiver according to the present invention comprises: an attenuation means which attenuates signal light that is a received wavelength multiple signal; a light source which outputs local light having a predetermined wavelength; an interference means which interferes the signal light that has been attenuated by the attenuation means with the local light and outputs first interfering light and second interfering light that is different from the first interfering light; a first photoelectric conversion means which photoelectrically converts the first interfering light and outputs a first electric signal; a second photoelectric conversion means which photoelectrically converts the second interfering light and outputs a second electric signal; an output means which outputs a difference signal between the first photoelectrically converted output and the second photoelectrically converted output; and a monitoring/control means which controls the attenuation means to thereby attenuate the signal light or controls the light source to thereby increase the local light, wherein the control of the attenuation means and the control of the light source are performed in such a manner that the intensity of a noise component of the difference signal that is generated as a result of the difference between the photoelectric conversion efficiency of the first electric signal relative to the intensity of the signal light and the photoelectric conversion efficiency of the second electric signal relative to the intensity of the signal light becomes equal to or smaller than a predetermined ratio relative to the intensity of the signal component of the difference signal.</p> |
