Patent ID: 9680283
Date: 2017-06-13
CPC Classifications: G02B,H01S,H04B

Claim:
1. An optical amplifier comprising: an input port; a bar-cross switch optically coupled to the input port; a first gain stage optically coupled between a first port of the bar-cross switch and an output port; and a secondary gain stage optically coupled between a second port and a third port of the bar-cross switch, wherein the secondary gain stage comprises a pump bypass structure coupled around an isolator and including a first pump wavelength WDM; wherein in a bar-state of the bar-cross switch the secondary gain stage is bypassed and in a cross-state, the secondary gain stage and the first gain stage are applied to an input light beam, wherein the secondary gain stage comprises a plurality of cascading gain stages, each comprising a separate gain-flattening filter and rare-earth doped fiber, and wherein one or more of the cascading gain stages uses remnant pump light from a previous stage.