| 摘要 |
PURPOSE:To provide a light-amplifier device with less sharp signal which is generated momentarily by switching a light switch,etc. CONSTITUTION:A fiber length L of an optical fiber type amplifier 1 is reduced shorter than its optimum length L0, where the optimum length Lg is a constant which is determined by the following, namely P0exp(-alphaL0)Pih, P0: connection excitation light power density to an optical fiber type amplifier 1, alpha: absorption coefficient per unit length of the optical fiber type amplifier 1, Pih: threshold excitation light power density generating gain. Furthermore, a gain G1 in a usage state at a saturation region satisfies the following expression, namely G0-G1<P0-Pmax where G0: small signal gain of the optical fiber type amplifier 1, P0: light power which is received by a light receiver 2 on a steady time, Pmax: maximum light-reception power allowable for the light receiver 2. |
