| 摘要 |
PURPOSE:To remove an up-convert after a base band detection, and to compensate the distribution of an optical fiber only by a base band processing by dividing signal components having a relative delay time of a mutual reversed polarity, overlapped on the base band in an optical area, in the base band detection such as an optical homodyne detection. CONSTITUTION:A received signal received from a transmitter 10 through an optical fiber transmission path 30, and a local oscillation light from a semiconductor laser light source 21 are inputted to a coupler 22 of a receiver 20, synthesized, and inputted to a Mach Zender type optical filter 61 with a ring oscillator, and this signal spectrum is divided into upper and lower side wave bands. Next, the spectrum divided into the upper side band is coherent-detected by a photodetector 62 by using a local oscillation light, and the spectrum divided into the lower side band is detected in the same way by a photodetector 63. Then, the distribution of the base band signal detected by the photodetector 62 generated at an optical fiber is compensated by using a delay equalizer 64, and the distribution of the signal detected by the photodetector 63 at the optical fiber is also compensated by using a delay equalizer 65. |
