摘要 |
Methods and apparatuses for determining the polarization state and for providing polarization control in optical fiber lasers and amplifiers. One embodiment of the invention is an optical fiber amplifying system including a circulator (260) having a first optical port (260a), a second optical port (260b) that is configured to output radiation received from the first optical port, and a third optical port (260c) that is configured to output radiation received from the second optical port; one or more amplifier stages (216) connected in series, together having an optical input (216a) optically coupled to the second port of the circulator, and an optical output (216b); and a polarization detector (240) having an optical input optically coupled to the third port of the circulator. Thereby the polarization state of the amplified radiation can be determined using radiation backscattered from the amplifying stage. |