| 摘要 |
PURPOSE:To provide an optical preamplifier wherein signal light is input from a Fabry-Perot laser resonator being a vertical multiple mode spectrum light source via a light transmission path, and while each signal component of a vertical mode included in a selected wavelength range is held, the signal light is amplified with a high S/N ratio and output to a receiver. CONSTITUTION:Signal light having a vertical multiple mode spectrum transmitted from a transmitter 100 is input via a transmitting optical fiber 200 to a light preamplifier 300, amplified by stimulated emission of Er excited by an amplifier optical fiber of an optical fiber amplifier part 310, sequentially passes through a Fabry-Perot fiber filter 320 and a bandpass filter 330 and is received by a receiver 400. Since the Fabry-Perot filter 320 has a transmissivity distribution corresponding to the vertical multiple mode of the signal light, each signal component of the vertical mode is held in a light component extracted from the signal light while most of noise components are removed. |
