Optical amplifier and control method therefor

An optical amplifier, comprising:

• a gain medium for amplifying a plurality of optical channels, the gain medium including a plurality of cores through which the plurality of optical channels propagate respectively and a cladding area surrounding the plurality of cores;
• a monitor configured to monitor a temperature of the optical amplifier and to produce a monitoring result;
• a first light source configured to emit a first light beam to excite the cladding area;
• a second light source configured to emit a plurality of second light beams to excite each of the plurality of cores individually;
• and
• a controller configured to control the first light source and the second light source based on the produced monitoring result,
• wherein
• the gain medium includes a first gain medium and a second gain medium;
• the second gain medium is connected in series directly to the first gain medium;
• the first gain medium is configured to be excited by the first light beam;
• and
• the second gain medium is configured to be excited by the plurality of second light beams.