A few-mode rare-earth-doped amplifier fiber has equalized gain for the supported signal transmission modes. In this arrangement, at least a proportion of the bulk material, in particular after it has been introduced into the chute, before it comes into contact with the extensive surface, is distributed in the radial andor tangential directionas seen from aboveat a scattering device which is assigned to at least one of the chutes and is preferably in the chute. A proximal end of a load beam is mounted on the actuator arm and a distal end of the load beam supports a head. These performance improvements and flexibility in usage allow for long term attitude sensing applications such as implantable prosthetics, micro-vehicle navigation, structural health monitoring, and long range smart munitions.