OPTICAL FIBER AMPLIFIER WITH DEVICE THAT MONITORS PUMP POWER AND INPUT POWER

摘要

PURPOSE: To obtain an optical fiber amplifier which can monitor input power even when the level of the power is low without using any complicated expensive circuit. CONSTITUTION: An optical fiber amplifier is provided with an amplifying section 1 equipped with a doped optical fiber and a pumping light source and a coupler 2 having four ports A1, A2, A3, and A4. In order to receive light in the wavelength domain of optical signals, optoelectric converters 4 and 9 connected to the port A3 of the coupler 2 from which part of light propagated in the direction opposite to the optical signals is outputted are provided. It is also possible to connect another optoelectric converter to the port A4 of the coupler 2 from which the optical signals are outputted.