ACTIVE OPTICAL FIBER AND METHOD FOR FABRICATING AN ACTIVE OPTICAL FIBER

摘要

A section of active optical fiber (11) which comprises an active core (1), an inner cladding layer (2) and an outer cladding layer (3). The diameter of said core (1) and the thickness of said inner cladding (2) change gradually along the length of said section of active optical fiber (11). This forms a tapered longitudinal profile enabling a continuous mode conversion process along the length of the section of fiber (11). The method for fabricating a section of tapered active optical fiber comprises the steps of fabricating a preform for drawing active optical fiber from said preform, installing said preform into a drawing tower, drawing optical fiber in said drawing tower and altering at least one of the two parameters including the take-off preform speed and the take-up fiber speed during drawing of the optical fiber.