Patent ID: 7440181
Filing Date: 2008-10-21
Classification: H01S

Abstract:
1. An optical apparatus, comprising: an optical fiber amplifier including an all-fiber polarization splitter-combiner, a polarization-rotating arrangement, and a gain-fiber, the amplifier being arranged such that light plane-polarized in a first polarization-orientation enters the amplifier via the polarization splitter-combiner, makes a first pass through the gain fiber in the first polarization-orientation, is polarization rotated by the polarization-rotating arrangement into a second polarization-orientation perpendicular to the first polarization-orientation, makes a second pass through the gain fiber in a second polarization-orientation, and exits the amplifier via the polarization splitter-combiner in the second polarization-orientation and wherein the polarization-rotating arrangement is provided by a 45 degree fiber-based rotator arranged so that the light will traverse the 45 degree fiber rotator twice prior to reentering the gain fiber.