OPTICAL COMMUNICATION SYSTEM

摘要

PURPOSE:To attain efficient signal amplification over a long range by accommodating an excitation light source driver and a wave synthesis coupler or the like into a transmission section and constituting an optical cable block with a function optical fiber. CONSTITUTION:A transmitter 14, an excitation light source driver 3 and a signal light/excitation light synthesis coupler 2 are installed in a station 11 as a transmission section 11. A signal light from the transmitter 14 is synthesized with an excited light having a comparatively short wavelength at the synthesis coupler 2 and the resulting light is propagated through a rate-earth group added fiber 1. The signal light is amplified by the energy when rare-earth group ions in the rare-earth group added fiber 1 excited by the excitation light are restored from the exciting state into the steady-state. The excitation light is cut off by an excitation light cut filter 7 installed at the termination of the optical cable block. Thus, the reception section receives only the amplified signal light through the rare-earth group added fiber 1.