Optical loop trasmission system

Abstract

Abstract PURPOSE:To eliminate the need for a bypass optical switch and to improve the reliability of the optical loop transmission system by using light signals with two kinds of wavelength as signals to be transmitted through an optical fiber, and processing the light signals with two wavelengths distinctively through a demultiplexer at each node station. CONSTITUTION:Signals with two kinds of wavelengths from a terminal 39 are used and demultiplexed through a demultiplexer 311 at each mode station 40 into wavelengths lambda1 and lambda2, and the signal with the wavelength lambda1 is reconverted by an optical receiver 34 into an electric signal, which is inputted to a processing circuit 38, converted by an optical transmitter 35 into the signal with the wavelength lambda1 again, and transmitted to the optical fiber 30 through a demultiplexer 312. The light with the wavelength lambda2, on the other hand, is passed through the optical coupler 32 composed of a half-mirror 33 and part of the signal enters the demultiplexer and exits from it to the optical fiber 30. The remainder of the signal is led out of the coupler 32 and reconverted by an optical receiver 36 into an electric signal, which is inputted to a processing circuit 38, converted again by an optical transmitter 37 into the signal with the wavelength lambda2, and reflected by the coupler 32 and transmitted to the optical fiber 30 through the demultiplexer 312. The light with the wavelength lambda1 is normally used and the light with the wavelength lambda2 is used as backup light.

Inventors

• 👤 Takahiro Asai
• 👤 孝弘 浅井
• 👤 Mitsuo Imai
• 👤 光雄 今井
• 👤 Hiroshi Kikuchihara
• 👤 菊地原　宏
• 👤 Yoshiki Takagi
• 👤 高木　慶樹

Bibliographic Details