FIBER RAMAN AMPLIFIER AND OPTICAL TRANSMISSION SYSTEM

摘要

PROBLEM TO BE SOLVED: To solve problems relating to light noise in a fiber Raman amplifier. SOLUTION: This fiber Raman amplifier (20) which has its pump conversion efficiency improved by increasing the gain is constituted by including a high-pass optical filter (22) in the amplifier structure. This filter can be formed as a 'dispersion type' filter which can include one or more individual components or is arranged a long fiber amplifier. The cutoff frequency of the high-pass optical filter is set to a little lower than the frequency of an input signal to be amplified. When this is used for constitution which has plural input signals, the cutoff frequency is controlled to a little lower than the lowest input signal frequency.