Light amplifying apparatus

A light amplifying apparatus adopting a redundant structure comprising:

• pump light sources for outputting pump lights;
• optical fibers to which a laser active metal composed of at least one selected from a group consisting of a rare-earth element and a transition metal is added;
• an optical coupler for combining pump lights from said pump light sources and distributing said pump lights to said optical fibers;
• and
• optical fibers which are longer than the coherence length of said pump lights from said pump light sources and each of which is inserted between each of said pump light sources and said optical coupler.

A light amplifying apparatus adopting a redundant structure comprising:

• pump light sources for outputting pump lights;
• optical fibers to which a laser active metal composed of at least one selected from a group consisting of a rare-earth element and a transition metal is added;
• an optical coupler for combining pump lights from said pump light sources and distributing said pump lights to said optical fibers;
• and
• oscillators for superimposing an alternating current on a driving current for said pump light sources.

A light amplifying apparatus adopting a redundant structure comprising:

• pump light sources for outputting pump lights;
• optical fibers to which a laser active metal composed of at least one selected from a group consisting of a rare-earth element and a transition metal is added;
• an optical coupler for combining pump lights from said pump light sources and distributing said pump lights to said optical fibers;
• an oscillator for superimposing an alternating current on a driving current for one of said pump light sources;
• and
• phase shifters for shifting the phase of said alternating current supplied from said oscillator and superimposing said alternating current on a driving current for said pump light sources with different phases from each other.