Patent ID: 8094370
Filing Date: 2012-01-10
Classification: G02B,H01S

Abstract:
1. An optical fibre amplifier system, comprising: one or more multimode pump laser diodes; a multiplexer for providing pumping radiation from the one or more multimode pump laser diodes to a rare-earth-doped multi-clad optical fibre having at least two cladding layers; and a passive multi-clad optical fibre having at least three cladding layers, one of the layers being an intermediate cladding layer, said passive multi-clad optical fibre being provided in line in a signal path for the laser signal between the multiplexer and the rare-earth-doped multi-clad optical fibre; wherein a fraction of stray radiation originating within the device is captured by at least one of the intermediate cladding layers of the passive multi-clad fibre, resulting in a reduction in the amount of stray radiation impinging upon the pump laser diodes.